arXiv digest — Antonio Marrone

arXiv digest — 2026-09-28

Mon, 28 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-28 — neutrino physics, flavour symmetries and astroparticle physics.

Natural Saturation Of The Sterile Neutrino Dark Matter Resonant Production By a High Lepton Flavor Asymmetry In Primordial Plasma
Shiu–Fuller resonant production gets a built-in ceiling: large asymmetries push the resonance late enough that active-neutrino oscillations redistribute and wash out $L_\alpha$, so the yield saturates. The result depends on the flavor structure of the initial asymmetry, leaving a two-decade window in $\sin^2 2\theta$ for next-generation X-ray searches. Directly relevant to keV sterile neutrinos in $\nu$MSM-type seesaw scenarios.
Topological Geometry of Neutrino Mass and Mixing
An $A_5$-based claim of parameter-free PMNS angles and masses: $\delta_{CP}=\pm\pi/2$, $\sum m_i\approx 72$ meV (NO), $m_{\beta\beta}\approx 8$ meV. The topic is squarely on target, but the mechanism (Yang–Baxter "geometric fracture" at $\sim 4\times10^{16}$ GeV) is unconventional and the single-author Letter needs scrutiny. Worth a quick check against golden-ratio $A_5$ mixing and current $\sum m_\nu$ bounds.
A Multidimensional General-Relativistic Boltzmann Solver for Neutrino Transport: Implementation, Discretization and Optimization
A full 6D GR Boltzmann transport in Gmunu, benchmarked against M1: about 10% differences in free-streaming luminosities, traced to the closure, while mean energies agree. It is a methods paper, but it bears on how reliable the supernova neutrino spectra are, which feed collective-oscillation and SN-detection studies at DUNE, JUNO and Hyper-K.
The geometry of solutions to the general sextic
Roots of the general sextic written in terms of Hilbert modular cusp forms. This is a concrete use of multi-modulus modular forms, the same objects that appear in multi-modulus modular flavor models.
Quantum-circuit simulation of three-flavor neutrino oscillations: vacuum, matter, and CP diagnostics
A two-qubit encoding of three-flavor oscillations, covering vacuum, MSW, supernova shock profiles, CP asymmetry and Lindblad decoherence. It is a compact, reproducible link between oscillation phenomenology and quantum-information measures.

arXiv digest — 2026-09-25

Fri, 25 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-25 — neutrino physics, flavour symmetries and astroparticle physics.

Sterile Neutrino Dark Matter Cries for GeV Heavy Neutral Leptons
First full $\nu$MSM parameter scan with complete quantum kinetic equations: low-scale seesaw, ARS leptogenesis and resonant keV sterile-neutrino DM simultaneously close only in a bounded region with GeV HNLs reachable by SHiP, LHC and future lepton colliders. Concrete predictions for HNL branching ratios, CP violation and LNV — a sharp, falsifiable seesaw benchmark.
Flavorful Lepton-Number-Violating SMEFT: Loop Mixing, $0νββ$ and Rare Meson Decays
One-loop mixing of $\Delta L=2$ dimension-7 SMEFT operators links quark and lepton flavor structures, so $0\nu\beta\beta$ becomes sensitive even to operators with heavy-generation quarks, while $K\to\pi\nu\nu$ and $B\to K^{(*)}\nu\nu$ cover complementary directions. Relevant for how flavor-symmetric UV models of LNV map onto $0\nu\beta\beta$ bounds; leptoquark example included.
High-quality axion from chain seesaw
A "chain seesaw" with vector-like mediators and an extra gauged $U(1)_{Y'}$ generates both neutrino and charged-fermion masses, with different chain lengths for up and down quarks producing hierarchies. The PQ symmetry is embedded in the gauge $U(1)_{Y'}$, solving axion quality — a flavor-hierarchy mechanism tied to seesaw and strong CP in one construction.
Nested Disappearing-Track plus Displaced-Vertex Topology at the HL-LHC: A Dual Long-Lived-Particle Signature of the Scotogenic Model
In the compressed scotogenic spectrum, the same small Yukawas that generate radiative neutrino masses make both $\eta^\pm$ and $N_2$ long-lived, giving a nested disappearing-track → displaced-vertex cascade with timing and back-pointing handles. A near-background-free HL-LHC probe of the couplings behind loop-induced neutrino mass.
Quantum field-theoretical description of solar neutrino oscillations
QFT (wave-packet-free) treatment of matter oscillations in the adiabatic approximation, with coherence-length estimates for solar production and detection channels. The claim that solar data are described by mass eigenstates without oscillations is decoherence in disguise — worth checking against the standard MSW picture.
The Flavor of Non-Abelian Orbifolds
Systematic derivation of the moduli-independent discrete flavor symmetries (and matter charges) of symmetric heterotic orbifolds with non-Abelian point groups, via Abelianization and space-group automorphisms, scanned over all 331 affine geometries. Direct input to the top-down, eclectic/modular flavor programme: a catalogue of which traditional flavor groups strings can actually deliver.
Plasma Effects Suppress Mixing-Induced Collisional Freeze-In
Flavour-covariant Kadanoff-Baym treatment shows the vacuum mixing angle in collisional freeze-in is replaced by its in-medium value, settling a conflict in the literature. Strong conclusion: sterile neutrinos in the keV-MeV range cannot be DM if produced from the SM plasma alone — a direct cut on non-resonant sterile-neutrino DM scenarios.
A Narrow Neutrino Window for the LZ Event
Neutrino-origin interpretation of the 248 keV LZ recoil: atmospheric neutrinos resonantly convert to a monoenergetic $N_1$ in a DM background, then upscatter to $N_2$ ($\sim250$ MeV) via gauged $U(1)_B$, kinematically allowed on Xe but forbidden on O and C. Constrains new heavy-neutral-lepton interactions using large neutrino detectors.
Anomaly in baryon number
Baryon- and lepton-number anomalies in the GUT-inspired $SO(5)\times U(1)\times SU(3)$ gauge-Higgs unification on warped space, summed over KK towers and localized on the UV/IR branes as a difference of $SU(2)_L$ and $SU(2)_R$ Pontryagin densities. Relevant to B and L violation in GUT-like extra-dimensional setups.
On the monomials of Poincaré Series of negative index
Monomial relations like $E_{14}=E_4E_{10}=E_4^2E_6$ are exactly the ring identities that fix modular-form multiplets in flavor models; here extended to weakly holomorphic Poincaré series with poles at the cusp.
Theoretical Perspectives on Flavour Physics
Compact status report on quark-flavour and B-meson CP violation through HL-LHC, Belle II and FCC-ee: the quark-side precision targets any unified lepton-quark flavor model must eventually meet.

arXiv digest — 2026-09-24

Thu, 24 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-24 — neutrino physics, flavour symmetries and astroparticle physics.

Sterile Neutrino Dark Matter Cries for GeV Heavy Neutral Leptons
First full $\nu$MSM parameter scan with complete quantum kinetic equations: type-I seesaw with three right-handed neutrinos simultaneously giving light masses, low-scale leptogenesis and resonantly produced sterile-neutrino DM. The viable region is closed in all directions, with GeV HNLs inside SHiP/LHC/future-lepton-collider reach and predictions for CP violation and LNV branching ratios.
Flavorful Lepton-Number-Violating SMEFT: Loop Mixing, $0νββ$ and Rare Meson Decays
Dimension-7 $\Delta L=2$ SMEFT operators with one-loop mixing: flavor structures feed into each other, so $0\nu\beta\beta$ becomes sensitive to operators with heavy-generation quarks, while $K\to\pi\nu\bar\nu$ and $B\to K^{(*)}\nu\bar\nu$ cover complementary flavor directions. Relevant for mapping flavor-model LNV sources onto $0\nu\beta\beta$ bounds; includes a scalar-leptoquark UV example.
Nested Disappearing-Track plus Displaced-Vertex Topology at the HL-LHC: A Dual Long-Lived-Particle Signature of the Scotogenic Model
Radiative (scotogenic) neutrino masses tested directly at colliders: in the compressed two-inert-doublet regime, the same $\mathcal{O}(10^{-3})$ Yukawas that set $m_\nu$ control the $N_2$ decay length, producing a nested disappearing-track + displaced-vertex cascade at HL-LHC. A concrete handle on the Yukawa texture behind neutrino mass.
A Diagnostic Method for Proto-Neutron Star Magnetic Fields by Supernova Fallback Neutrinos
Supernova fallback neutrino spectra as a diagnostic of proto-neutron-star magnetic fields via a hardness ratio above/below 30 MeV. The applicability depends explicitly on the neutrino mass ordering, so it is relevant to supernova-neutrino phenomenology at JUNO/Hyper-K/DUNE.
Precise QCD Predictions for the Scotogenic Model at Colliders
First NLO QCD + parton-shower predictions for scalar and heavy-neutrino production in the Scotogenic model at 14 and 100 TeV, with a public UFO release (SM_Scoto). A practical tool for collider tests of radiative neutrino-mass models; complements the displaced-signature study above.
Tension between MiniBooNE and MicroBooNE within a 3+1 Sterile Neutrino Framework using Simulation-Based Inference
Consistent joint MiniBooNE + MicroBooNE (BNB and NuMI) fit to 3+1 with simulation-based frequentist inference and trials-calibrated parameter-goodness-of-fit tension. The 3+1 preference drops to $2.7\sigma$ with a $\geq 2.5\sigma$ PG tension: a solid reference point for the state of eV-scale sterile neutrinos in global fits.
Supernova Gamma-Ray Echo as an Astrophysical Near Detector for Galactic Neutrino Propagation
The 511 keV gamma-ray echo of a Galactic supernova burst acts as a near detector for the emitted $\bar\nu_e$ fluence, turning averaged active-sterile oscillations of pseudo-Dirac neutrinos into a measurable near-far deficit, with reach down to $\delta m^2\sim10^{-18}\,\mathrm{eV}^2$. A new handle on the Dirac vs Majorana question; also applies to neutrino decay.
Earth-density effects in long-baseline neutrino experiments in a four-flavor (3+1) sterile-neutrino framework
Earth-matter bias on the reconstructed $\delta_{CP}$ at long baselines in a 3+1 framework with PREM, including an analytic account of the NC potential acting as an effective NSI-like term after integrating out the fast $\Delta m^2_{41}$ oscillation. Bias negligible below 5000 km, reshaped by the sterile sector for core-crossing trajectories.
Resonant neutrino flavor conversion within dark matter spikes
Coherent forward scattering on a dark-matter spike around AGN black holes induces resonant flavor conversion of 100 TeV neutrinos; the IceCube flavor triangle already disfavors some muon-damped configurations. A new astrophysical-environment probe of neutrino-DM interactions, NSI-like in structure.
Complementary Time- and Distance-Based Methods for Cosmogenic $^{9}$Li/$^{8}$He Background Estimation
Improved estimate of the cosmogenic $^9$Li/$^8$He correlated background for IBD, combining muon-categorized time fits with a muon-track distance distribution; more than 40% smaller statistical uncertainty. Directly relevant to reactor-oscillation analyses in large liquid-scintillator detectors such as JUNO.
Construction of vector-valued adelic automorphic forms
Adelic version of Scheithauer's lift from scalar to vector-valued modular forms for the Weil representation: the same vector-valued structure that organizes modular-form multiplets in modular flavor symmetry models.
Modular integrals for individual modular knots
Weight-2 modular integrals for $\mathrm{SL}_2(\mathbb{Z})$ built from individual modular knots, answering the Choie-Zagier question: a striking geometric/topological angle on the modular-group machinery used in flavor model building.

arXiv digest — 2026-09-23

Wed, 23 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-23 — neutrino physics, flavour symmetries and astroparticle physics.

Testable neutrino mass and TeV-scale leptogenesis in a $D_4$ inverse seesaw model
Discrete-flavor ($D_4$) inverse seesaw that ties oscillation data (NO and IO), resonant-like TeV leptogenesis with pseudo-Dirac pairs, and cLFV rates in reach of next-generation searches. A compact benchmark for how dihedral groups constrain low-scale seesaw textures and what they predict beyond oscillations.
Three-Flavoured Thermal Leptogenesis Without Tuning
Type-I seesaw plus a singlet scalar with off-diagonal $\phi N_i N_j$ couplings: new CP sources in $N$ decays without extra washout, giving electroweak-scale leptogenesis with a hierarchical $N$ spectrum — no quasi-degeneracy, no tree/loop cancellations. Analytic CP bound and full density-matrix treatment.
Restoring minimal modular neutrino masses via Kähler $R$-parity violation
Revisits Feruglio's original modular $A_4$ model and shows that in supergravity the Kähler potential induces bilinear $\epsilon_i L_i H_u$ terms fixed by $Y(\tau)$ and its derivatives. This rescues the single-modular-multiplet neutrino sector for both orderings, with distinct $\sum m_\nu$ predictions for Weinberg vs. flavon-fermion seesaw — directly on the Kähler-ambiguity problem of modular flavor.
Future Muon Physics Experiments: Muon Beams and Experimental Apparatus
A review of the upcoming CLFV programme ($\mu\to e\gamma$, $\mu\to 3e$, $\mu$–$e$ conversion, muonium–antimuonium) and the beams behind it. These are the sensitivities that low-scale seesaw and flavor-symmetric models, such as the $D_4$ inverse seesaw above, are tested against.
Classification of order-two T-duality orbifolds at the SO(12) free fermionic point
A systematic classification of $\mathbb{Z}_2$ asymmetric orbifolds (T-folds) on the SO(12) lattice at the free-fermionic point. It maps non-geometric orbifold vacua, the terrain where the outer-automorphism and T-duality origin of modular flavor groups is explored, though here in type II without a flavor sector.
Resonant neutrino flavor conversion within dark matter spikes
An NSI-like, flavor-dependent matter potential from $\nu$–DM forward scattering in AGN spikes, with MSW-type resonant conversion before escape. Confronting IceCube flavor-triangle data already disfavours muon-damped $p\gamma$ scenarios — a new use of astrophysical flavor ratios as a probe of non-standard neutrino interactions.
Complementary Time- and Distance-Based Methods for Cosmogenic $^{9}$Li/$^{8}$He Background Estimation
$^9$Li/$^8$He is a leading correlated IBD background for large reactor-antineutrino detectors like JUNO. A distance-constrained joint time fit cutting the statistical error by more than 40% feeds directly into the background budget of the $\Delta m^2_{31}$, $\theta_{12}$ and mass-ordering fits.
Fast Surrogate for the Earth Matter Effect on Solar Neutrinos
A CNN emulator for Earth-crossing regeneration of solar neutrinos (day–night asymmetry), about 2% accurate and 60× faster. Because it learns only the propagation, it can be reused in NSI or new-physics scans of $\Delta m^2_{21}$ and $\theta_{12}$ — a practical tool for global solar and KamLAND/JUNO fits.
Goodness-of-fit for multi-distribution neutrino cross-section measurements with shared events
Multiple differential cross sections extracted from the same events give rank-deficient covariances and inflated $\chi^2$. The range-projected $\chi^2$ with $N_\text{bins}-N_\text{null}$ d.o.f. fixes this. Relevant to $\nu$–Ar cross-section inputs and interaction-model tuning for DUNE-era oscillation analyses.
Neutrino Astronomy at High Energies - An Experimental Review
An authoritative historical and status review of TeV–PeV neutrino astronomy from one of the field's founders. Useful as a reference for the astrophysical-neutrino side (fluxes, source identification, next-generation telescopes) that flavor-ratio and new-physics studies build on.
A New Probe of Strongly-Interacting Dark Sector using Neutrino Telescopes
UHE neutrinos scattering resonantly on the C$\nu$B into dark vector mesons would leave absorption dips in the cosmic neutrino spectrum. It turns the relic-neutrino background into a spectroscopic target for IceCube-Gen2 Radio, in the same family as secret-interaction dips.
The Super-Composite Higgs
Agashe–Giudice–Rattazzi–Sundrum combine SUSY and partial compositeness so that the flavor hierarchies come from dynamics, not symmetry. It is the main rival to flavon and modular explanations, and it comes with testable eEDM, gravitino and FCC-hh predictions.
Iterated integrals for generalized Appell functions
Mock-modular completions written as iterated Eichler integrals of modular forms. Worth reading if you want the non-holomorphic side of modular flavor, such as polyharmonic Maaß forms in non-SUSY models, on firmer mathematical ground.

arXiv digest — 2026-09-22

Tue, 22 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-22 — neutrino physics, flavour symmetries and astroparticle physics.

Three-Flavoured Thermal Leptogenesis Without Tuning
A singlet scalar with off-diagonal couplings $-y_{ij}\phi N_iN_j$ buys new CP sources in heavy-neutrino decays without the usual washout penalty, so successful leptogenesis survives with a hierarchical RH spectrum down to the electroweak scale. That removes both standard escapes — quasi-degeneracy tuning and tree/loop cancellations in $m_\nu$ — and the result is quoted from fully flavoured Boltzmann and density-matrix equations, not the one-flavour approximation.
Baryogenesis and dark matter freeze-in from Higgs interactions
Freeze-in dark matter as two gauge-singlet Majorana fermions plus a TeV electroweak-doublet VLF: a CP phase in the feeble Yukawas splits the charge asymmetry between the VLF and SM sectors, and the baryon asymmetry follows from SM equilibrium alone, with no $B-L$ violation needed. Adding VLF Yukawas that do break $B-L$ opens the space and turns on lepton flavour violation.
Probing Matter Unification through Higgs Physics at the LHC
Minimal low-scale quark-lepton unification with an inverse seesaw: the new Higgs couplings are fixed by the unification structure, so the scalar spectrum and its third-generation-dominated decays become a direct probe of the matter-unification pattern. Useful as a concrete counterpoint to the usual leptoquark-only searches, and the parameter space is already bitten by current LHC $\tau$ and top channels.
Three-Body Holonomy as a Toy-Model Mechanism for Family Triplication and Mass Hierarchy in (1+1) Dimensions
A deliberately minimal toy: a genuine three-body holonomy in (1+1)d punctures the relative configuration space and a $C_3$-invariant Hermitian mass operator gives three masses $M^{[k]}=M_0+2\Delta\cos[(\theta_3+2\pi k)/3]$, with a parametrically light branch from cancellation. Family triplication and hierarchy from a phase rather than a flavour group — and the Schur complement keeps the rephasing invariant $\mathrm{Re}(t_{12}t_{23}t_{31})$ visible in the light sector.
Weighted Generalizations of Zagier's Phenomenon
Weighted sums over the $PGL_2(\mathbb{Z})$ orbit of piecewise-polynomial functions with two irrational roots, shown to be bounded, 1-periodic, continuous, and to obey a reciprocal functional equation — recovering Zagier's constancy result. The same modular-group machinery that underlies quantum modular forms, in an elementary setting worth borrowing from.
$D$-elliptic modular curves $X_0(N)$
A method to decide whether $X_0(N)$ admits a degree-$D$ rational map to some elliptic curve over $\mathbb{Q}$, now free of the odd-analytic-rank and technical restrictions, with all $D$-elliptic $X_0(N)$ classified for $D\le100$. Some maps found are not explained by degeneracy, quotient or modular parameterisation — unexpected structure on exactly the curves whose modular forms carry $\Gamma_0(N)$ flavour models.
Non-Archimedean Poincaré series and geodesics on the Bruhat-Tits tree
Poincaré series on the Drinfeld half-plane built from meromorphic 1-forms attached to geodesics on the Bruhat-Tits tree, with explicit linearly independent families for $\Gamma(\mathfrak{n})$ and $h$, $\Delta$ recovered as Poincaré series. The function-field mirror of the modular forms used in flavour model building, where the tree makes the cusp behaviour combinatorial.
IceCube Upgrade status and perspectives
Five Upgrade strings went in during the 2025/26 austral summer. The dense infill targets atmospheric $\nu$ selection and reconstruction at a few GeV — i.e. the oscillation channel — and the new calibration devices will be applied retroactively to archival data, so existing IceCube event directions and energies are about to move. Worth tracking before quoting their oscillation contours.
Non-standard cosmic strings with amazing profiles
Gauging $B-L$ and cancelling the anomaly with $\nu_R$ forbids the Majorana term, so the RH mass has to come from a separate complex scalar — a clean, explicitly Dirac corner of the parameter space. The paper solves the coupled gauge-Higgs equations numerically for cosmic-string profiles; the tension survives CMB and GW bounds, and high winding numbers give overshooting and co-axial profiles.
Detailed investigation on the Geant4 simulation of alpha particles in liquid scintillator detector
Geant4 11.4.2 against SNO+ alpha data in a 4 m LAB-based scintillator cube, with Birks quenching applied per step. The conclusion is that delta-electron fluctuations dominate the intrinsic resolution (secondary-track variance 1.01–1.12 times the total), and that the production threshold matters more than the EM model. Anyone whose sensitivity rides on liquid-scintillator energy response should read the threshold discussion.
The phenomenology of Axion Relic Pockets
Axion relic pockets — false-vacuum regions held open by a hot axion gas — converted to photons in atomic electric fields, giving isotropic electromagnetic cascades with upward-going showers as the smoking gun. First terrestrial limits come from IceCube data. The observable is a neutrino telescope used as a calorimeter, so the systematics are the familiar ones.
Probing axion-like particle couplings to leptons via the $γγjj$ signal at the FCC-ee
FCC-ee at the $Z$ pole, $e^+e^-\to\gamma\gamma jj$, with the $\mathbf{c}_R=0$ and $\mathbf{c}_R=\mathbf{c}_L$ scenarios probing the ALP-neutrino coupling $\mathrm{Tr}(g_{a\nu\nu})/f_a$ down to $\sim4\times10^{-3}\,$GeV$^{-1}$ for $m_a=45$–80 GeV with polarized beams. A rare direct handle on ALP couplings to the neutral lepton sector.
The detector system of the SHiP/NA67 experiment at CERN
SHiP/NA67 detector layout as frozen for the 2032–33 commissioning runs: veto and timing detectors and a straw tracker for feebly-interacting particle searches, plus small-transverse-size high-granularity calorimeters for all-flavour neutrino reconstruction. The tau-neutrino programme is the part to watch.
A New Probe of Strongly-Interacting Dark Sector using Neutrino Telescopes
Turns the C$\nu$B into a target: dark vector mesons of a confining dark sector are produced resonantly in high-energy $\nu$ scattering on relic neutrinos, leaving an absorption line whose position maps the dark resonance spectrum rather than a featureless attenuation. Reach claimed for IceCube-Gen2 Radio. Relevant to any bound on $\nu$ secret interactions.
Luminosity Signatures of Dark Sector Particles from Black Hole Evaporation in Neutron Stars
Microscopic black holes from accumulated dark matter in neutron stars: Hawking-radiated mediators long-lived enough to escape the star decay into high-energy neutrinos and photons. The energy-integrated angular profile turns out nearly independent of the hole temperature, set instead by $c\tau_S/D$ — so the angular shape alone will not separate this from DM annihilation, but the energy-resolved distributions will. Heavy neutral leptons are among the mediators considered.
Multi-wavelength Behaviour and Lepto-hadronic Modeling of PKS 0215+015 Around the Epoch of IceCube-220225A
Lepto-hadronic modelling of the FSRQ PKS 0215+015 around IceCube-220225A. A leptonic SED fit works; the co-accelerated proton population stays radiatively subdominant but needs a kinetic luminosity two orders of magnitude above equipartition, and the predicted $\nu$ flux falls well short of a single 154 TeV detection. Another association that does not survive its own energetics.
Goodness-of-fit for multi-distribution neutrino cross-section measurements with shared events
When several differential cross sections come from one event sample, the shared events impose exact linear constraints and the covariance matrix is rank-deficient — numerical noise then makes it invertible and inflates $\chi^2$ arbitrarily. The range-projected $\chi^2$ restores $N_{\rm bins}-N_{\rm null}$ degrees of freedom. Directly transferable to any global fit built on correlated sub-samples.
Interpreting the LZ 248 keV Event using Dark QCD
The LZ 248 keV nuclear-recoil candidate read as composite inelastic dark matter: a dimension-ten operator splits the lightest dark baryon of a confining $SU(3)_{\rm D}$ into two Majorana states, with endothermic scattering through a leptophobic baryon-number vector. A 1 TeV dark baryon and a 300 keV splitting land inside LZ's two-sided interval and survive the solar-neutrino and dijet constraints — worth a look for how quickly a single event gets a spectrum-level interpretation.
Quantum modularity in refined topological recursion
Refined topological recursion on the Weber curve: the Borel-Laplace sum of the free energy is the Barnes double gamma, and — unexpectedly — the generating function of the Stokes constants along each ray is a Jacobi quantum modular function. Quantum modularity emerging from resurgence rather than being imposed; the same objects that show up when modular forms are pressed into flavour model building, arriving from the other side.

arXiv digest — 2026-09-21

Mon, 21 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-21 — neutrino physics, flavour symmetries and astroparticle physics.

Leptogenesis and Planck-scale black hole remnants in a Pati-Salam cosmology
Pati-Salam ties $M_R$ to the SU(2)$_R$ breaking scale, and cosmology then forces both the Yukawa and the heavy neutrino mass well below it. The sharp claim is an exclusion: remnant dark matter and non-thermal leptogenesis cannot coexist, and only a thermal asymmetry with PBHs near $10^6$ g accommodates the baryon asymmetry, the relic abundance and the breaking scale together.
AutoTherm: Automated Thermal Field Theory rates for cosmology
A FeynRules-to-rate pipeline that automates Hard Thermal Loop resummation, the step that usually makes thermal production rates model-dependent by hand. It reproduces — and in places corrects — the literature on ultrarelativistic right-handed neutrino production, so it is directly usable for leptogenesis washout rates, with three HTL implementations whose spread estimates the higher-order theory error.
FIMP dark matter in the scotogenic model at low-reheating temperatures
Freeze-in singlet fermion dark matter in the scotogenic model with an instantaneous low reheating temperature. Lowering $T_{\rm rh}$ reshapes the viable $N_1$ region substantially while keeping $\mu\to e\gamma$ and direct-detection bounds satisfied — the radiative-mass and dark-matter sectors are the same parameters, so the LFV constraint does real work.
Resurrecting Electroweak Dark Matter via Type-II Seesaw in light of recent LZ Event
Inert lepton doublet dark matter revived by a type-II seesaw: the scalar triplet supplies both the inelastic mass splitting and extra annihilation channels, pushing the relic-density mass well above the TeV scale and out of the solar-capture and direct-detection constraints — while the same triplet vev gives the sub-eV neutrino masses. One field doing both jobs is the point.
Calculating Axion-Matter Couplings in String Theory
Axion-matter couplings computed explicitly in heterotic Calabi-Yau compactifications with line-bundle vector bundles, using neural networks for the Ricci-flat and Hermitian Yang-Mills metrics. The result is a clean hierarchy: model-dependent axions couple DFSZ-like with $\mathcal{O}(1)$ coefficients, the model-independent axion is $\alpha_{\rm YM}$-suppressed, KSVZ-like. The same overlap-integral machinery is what fixes Yukawas in these models.
A Type IIB Dualifold
Type IIB orbifolded by the $\mathbb{Z}_3$ duality symmetry at $\tau=e^{2\pi i/3}$ — the same fixed point where modular flavour models sit, here used to build a ten-dimensional chiral non-supersymmetric theory. The discrete gauge symmetry is the automorphism group of $\Gamma^{2,2}(A_2)$ and anomalies cancel through a $\mathbb{Z}_3$-valued topological Green-Schwarz mechanism.
Galois deformation rings and modularity in the residually reducible case
Modularity for residually reducible $p$-adic Galois representations without a self-duality assumption: the reduced universal deformation ring is shown to be a DVR via pseudocharacters and Selmer-group bounds, with Bellaïche-Chenevier's reducibility ideal maximal and principal. Applied with a Klosin congruence between Hermitian modular forms, it gives modularity for 4-dimensional representations of $\mathbf{Q}(i)$.
Real quadratic fields and finite quantum dilogarithms I
Stark-Shintani ray class invariants for real quadratic fields are proved algebraic, through special values of Faddeev's modular quantum dilogarithm. The mechanism is an overdetermined polynomial system matching Andersen-Kashaev's quantum dilogarithm on a product of cyclic groups, so the values categorify Izumi fusion rings and algebraicity follows from Ocneanu rigidity — modular objects controlling arithmetic through a finite categorical structure.
Annular Frobenius Classification of p-adic Stieltjes--Schwarzian Equations
Annular normal forms and Frobenius structures for $p$-adic Schwarzian equations, applied to the reducible modular equations $\theta^2y-\ell^2E_4y/144=0$ with $\gcd(\ell,6)=1$: exactly two annular types at every prime, and the least $s$ for which Frobenius under $q\mapsto q^{p^s}$ exists. $E_4$ and $q$-expansions in a $p$-adic setting, for anyone who thinks about modular forms arithmetically.
Difference of the Sum of All Odd and Even Overlined Parts of Overpartitions
The difference between odd and even overlined parts of overpartitions, with a closed-form generating function and congruences proved through half-integral weight modular forms. A small, self-contained instance of the standard route from a combinatorial statistic to a congruence via modularity.
Anomalous Matter Potentials in Earth's Inner Core: A Phenomenological Probe of Dark Matter and Light Sterile Neutrinos
Three-flavour matter effects re-examined where PREM is least constrained. A fractional enhancement of the electron-sector potential confined to the inner core leaves all but near-antipodal trajectories untouched, then moves $P(\nu_\mu\to\nu_\mu)$ by tens of percent and $P(\nu_\mu\to\nu_e)$ by more than 100% — with a neutrino/antineutrino asymmetry that mimics intrinsic CP violation. A degeneracy worth knowing about before reading a $\delta_{CP}$ fit from atmospherics.
AGN and DSNB Neutrino Oscillation in Dark Matter Background
Replaces the MSW potential with a $\nu\phi$ effective potential from an ultralight scalar background and propagates AGN (NGC 1068, TXS 0506+056) and DSNB fluxes through it. The observable is the flavour ratio at Earth, compared against IceCube ternary-plot sensitivities and, for the DSNB, the combined HK/DUNE/JUNO reach.
First Measurement of Differential Cross Sections in Kinematic Imbalance Variables with Electron Neutrino Interactions Using the MicroBooNE Detector
First kinematic-imbalance differential cross sections for $\nu_e$ on argon, from MicroBooNE's full $1.3\times10^{21}$ POT. These variables isolate Fermi motion, multinucleon processes and final-state interactions — the systematics that propagate straight into DUNE's $\nu_e$ appearance. Tensions with generators appear where FSI should be least dominant, which is the uncomfortable place for them to appear.
Charged lepton flavor violating decays and $(g-2)_{e_a}$ in an extended standard model with singlet and triplet leptoquarks
An $SU(2)_L$ singlet plus triplet leptoquark, with the correlations between $\Delta a_{e,\mu}$, $e_b\to e_a\gamma$ and $h,Z\to e_b e_a$ worked out. The useful negative result: the model cannot deliver $|\Delta a_e|\sim10^{-13}$ and $|\Delta a_\mu|\sim10^{-10}$ at once, and each choice suppresses a different set of LFV rates below reach.
Test of lepton flavor universality with $\bar{B} \rightarrow D^{(*)} \tau^{-} \bar{\nu}_{\tau}$ and $\bar{B} \rightarrow D^{(*)} \ell^{-} \bar{\nu}_{\ell}$ decays at Belle II
The most precise hadronic-tag determination of $R(D^{(*)})$: $R(D^*)=0.242\pm0.019\pm0.016$, $R(D)=0.439\pm0.055\pm0.046$ from $387\times10^6$ $\Upsilon(4S)$ decays. Consistent with the Standard Model, which continues to narrow the room a flavour-structure explanation of the old anomaly could occupy.
Neutrino Emission from Proton Photon Jet Interactions in Microquasars
Relativistic MHD microquasar jets with a ray-tracing step that turns the simulation into synthetic neutrino images and spectra for a stationary observer, restricted to the $p\gamma$ channel. Useful as a template for what galactic point sources should look like to a detector, with the $pp$ contribution deliberately left out.
LUX-ZEPLIN's Stairway to Hea$\nu$en: limits on elastic scatters of dark matter from solar capture
Reverse-engineers Wilson coefficients from the LZ 250 keV recoil for each elastic operator that fits it, then computes solar capture and confronts the resulting annihilation flux with IceCube and Super-Kamiokande. Much of the weak-scale mass range that would explain the event is excluded, most strongly by annihilation to $\nu\bar\nu$.
The large sieve for square moduli under Hooley's hypothesis $R^*$
A conditional improvement of the Baier-Zhao exponent for Zhao's large sieve with square moduli, resting on one observation — a sum of modular square roots is, after completing and evaluating quadratic Gauss sums, a Salié sum of a shorter length. Worth a look for a second reason: Section 1.9 sets out what the author and Claude each contributed.
Discrete Gauging of 5d $\mathcal{N}=1$ $E_n$ SCFTs
Gauging discrete symmetries of the 5d rank-one $E_n$ SCFTs that act on the Higgs branch but fix the Coulomb branch, with the quotients realised as Coulomb branches of wreathed magnetic quivers. The flavour algebras read off the moment maps land exactly on the fixed-point subalgebras of $\mathfrak{e}_n$ — discrete symmetry acting on an exceptional flavour group, from an unfamiliar direction.

arXiv digest — 2026-09-18

Fri, 18 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-18 — neutrino physics, flavour symmetries and astroparticle physics.

On the Maximal CP Violation in Leptogenesis with Two Right Handed Neutrinos
Exact analytic upper bound on the CP asymmetry in the minimal two-RHN type-I seesaw, obtained from the roots of the quartic that encodes successful leptogenesis. It is tighter than previous analytic results and falls below Davidson-Ibarra by nearly two orders of magnitude for inverted ordering, which directly stiffens the lower bound on the lightest RHN mass.
Lukewarm inflation and the QCD axion
Right-handed neutrinos in the 0.1-1 GeV window drive a late warm-inflation stage that damps coherent axion oscillations, letting $f_a$ sit near the GUT scale without tuning the misalignment angle. An RHN sector doing cosmological work beyond leptogenesis, complete with an early-matter era dominated by the lightest $N$ and $N_{\rm eff}$ signatures.
Probing Scalar-Induced First-Order Phase Transitions with the Diffuse Supernova Neutrino Background
A light neutrinophilic scalar thermalised in the proto-neutron-star core splits the DSNB into a prompt component and a spectrally narrow delayed one from first-order-phase-transition scalar decays. The signal depends sharply on the mass ordering, and Super-Kamiokande data already cut into inverted-ordering, quasi-degenerate parameter space.
Commissioning and Performance of the Time-of-Flight Detector for the T2K Neutrino Oscillation Experiment
The ND280 upgrade is the systematics backbone of the T2K $\delta_{CP}$ measurement, and this is the full commissioning record of its Time-of-Flight layer: 169 ps in situ per bar, 2.6 cm longitudinal. Those numbers set how well out-of-tracker backgrounds and track direction are controlled in the near-detector constraint that propagates into the oscillation fit.
After 60 years, here comes the Sun
Reactor antineutrinos have made the propagation uncertainty in solar flavour conversion negligible, so solar neutrinos can finally be turned back on the Sun. The paper argues what it takes to breach the $^{14}$C wall and reach Standard-Solar-Model precision on the pp flux: useful framing for where the solar sector goes once $\theta_{12}$ is no longer the target.
Mineral Detection of Neutrinos and Dark Matter 2026 Proceedings
Mineral and paleo-detectors as a neutrino channel: reactor monitoring on laboratory timescales, and Gyr-integrated astrophysical-neutrino and cosmic-ray fluxes read out of ancient crystals. Worth a scan for the directional nuclear-recoil reach and the current state of the microscopy readout.
Design and characterization of large-size monolithic layers of 3D-segmented plastic scintillator
Scaling the glued-cube monolithic technology to $48\times48$ optically isolated scintillating voxels, the module size ton-scale 3D-granular detectors require. This is the manufacturing step that decides whether SuperFGD-style tracking and sub-ns timing stay affordable at the next neutrino-detector mass.
Distinguishing Coupled Dark Matter Dark Energy from Kinematic Phantom Crossing
Coupled dark-energy-dark-matter models reproduce $w_0w_a$CDM at the background level but leave a growth signature, and generate an analytic coupling-neutrino-mass degeneracy $\sum m_\nu \propto f_c^2 \alpha^2$ recovered against DESI DR2, ACT DR6 lensing and RSD. A reminder that cosmological $\sum m_\nu$ bounds are only as model-independent as the dark sector assumed.
Neutralino Dark Matter in SU(5) after H.E.S.S. and Direct-Detection Searches
Gamma-ray line and direct-detection limits translated back into GUT-scale boundary conditions: the 1 TeV pure wino is essentially excluded by H.E.S.S. for both cusped and cored profiles, Higgsino and wino-Higgsino by direct detection, while a bino near thermal saturation survives. A clean read on how much non-universal-gaugino SU(5) parameter space is still standing.
Collective flavor conversion in dense neutrino plasmas
Fiorillo's quasiparticle reformulation of collective flavour conversion: flavour waves quantised as flavomons, instabilities recast as stimulated decays $\bar\nu_e \to \bar\nu_\mu \psi$. The most coherent available bridge between the dispersion-relation literature and the numerical flavour-kinetics results for supernovae and neutron-star mergers.
Lepto-hadronic modeling of blazars associated with well-reconstructed high-energy neutrino events
Six blazars with single gamma-ray counterparts to well-reconstructed IceCube events, modelled lepto-hadronically with the parameter space pushed to maximise neutrino output. Emission stays leptonic-dominated with subdominant hadronic cascades and rates up to $5\times10^{-2}$ per year, bounding how much individual associations can contribute to the diffuse flux.
The Geometry of the CKM matrix, the Standard Model and RG fixed points
The CKM matrix treated as a point of the double coset $T\backslash SU(3)/T$, with a Riemannian metric whose point singularities reproduce the known RG fixed points and whose discrete backbone is the Weyl group $S_3$, realised as a hexagon. A geometric, discrete-group reading of mixing that is worth comparing with how $S_3$ and $A_4$ models organise the flavour puzzle.
Investigating the influence of the full-kinematics treatment for charged-current processes in binary neutron star mergers
Three prescriptions for charged-current weak rates compared inside full binary-neutron-star merger simulations with M1 transport. The elastic approximation inflates the dynamical ejecta mass and the early neutrino luminosities and shifts the $A\in[90,125]$ yields, quantifying how much weak microphysics the merger neutrino signal actually carries.
Conformal blocks and braiding matrices for RCFTs I: Virasoro minimal models
Braiding F-matrices for Virasoro minimal models, with the conjecture that their squared entries live in cyclotomic extensions of $\mathbb{Q}$ - the same arithmetic of roots of unity that controls Clebsch-Gordan coefficients and ring relations among modular forms of level $N$. The closing remarks on the holomorphic modular bootstrap make the connection to modular flavour symmetry explicit.
On the Hiraga-Ichino-Ikeda conjecture on formal degrees for $\mathrm{G_2}$
A result on formal degrees for $\mathrm{G}_2$ proved by routing through triality on $\mathrm{PGSO}_8$ and the adjoint group of type $E_6$ - exactly the exceptional chain that GUT model building keeps rediscovering. Reading it as a physicist is a reminder that triality is a computational tool with real leverage, not a decorative symmetry of $SO(8)$.

arXiv digest — 2026-09-17

Thu, 17 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-17 — neutrino physics, flavour symmetries and astroparticle physics.

Asymmetric Inelastic Dark Matter and the LUX-ZEPLIN event
The DM asymmetry comes from CP-violating out-of-equilibrium decays of heavy Majorana fermions produced nonthermally from inflaton decays — leptogenesis machinery pointed at a dark sector. Because the abundance is set by the asymmetry rather than freeze-out, solar capture leaves no annihilation signal and the IceCube constraint that kills Higgsino interpretations of the LZ 250 keV event evaporates.
Quantum Seesaw Cosmology: A Heating Phase from Pauli Blocking
Reheating through right-handed neutrinos with Pauli blocking taken seriously: once the RHNs saturate a restricted momentum region, expansion keeps opening states that fresh scalar decays refill, holding the physical RHN density roughly constant. The result is an inverted temperature scaling, $T \propto a^{+3/8}$ against the usual $a^{-3/8}$ — a seesaw-driven cosmological history with a genuinely different thermal record.
Gravitational lensing of neutrinos through the lens of decoherence
Decoherence sourced by gravitational lensing when the potential is not smooth: splitting it into a smooth part plus a stochastic population of compact clumps produces random relative phases between mass eigenstates, which average into a damping of flavour coherence. It turns astrophysical neutrino flavour ratios into a probe of dark-matter substructure, and adds a propagation systematic that is not on the usual list.
Reheating Bounds from Thermal GUT Monopole Production
Thermal GUT monopole abundance recomputed with full relativistic corrections and annihilation enhanced by radiation emission and scattering off gauge bosons, SM fermions and superpartners. The output is a clean constraint on the ratio $T_{\rm RH}/T_{\rm GUT}$ — below $0.55$ from the DM density, $0.45$ with Parker, $0.35$ once Super-Kamiokande is folded in — i.e. a cosmological bound that any GUT-breaking pattern has to clear.
The Geometry of the CKM matrix, the Standard Model and RG fixed points
The CKM matrix read as a point of the double coset $T\backslash SU(3)/T$ with a Riemannian metric: point singularities turn out to be the known RG fixed points, joined by line singularities, with the $SU(3)$ Weyl group $S_3$ organising the whole picture as a hexagon in $V$. A geometric handle on mixing where the discrete group is a consequence of the coset rather than an imposed flavour symmetry.
Graded Algebras of Modular Forms and Sign Changes of Fourier Coefficients for Eta Quotients
Explicit graded algebras of modular forms for $\Gamma_0(N)$ at $N=8,12,16,20,32$, integral and half-integral weight, with quadratic characters, generated by eta quotients and with the relations worked out. These are exactly the levels used to build modular flavour models, and an eta-quotient basis with explicit relations is the practical ingredient for writing Yukawas as modular forms of a given weight.
After 60 years, here comes the Sun
Sixty years on, the argument is flipped: reactor antineutrinos have fixed the solar oscillation parameters so tightly that the propagation uncertainty is no longer the limiting one, and solar neutrinos can finally be used to read the Sun rather than the mixing. The obstacle is now detection: the $^{14}\mathrm{C}$ background walls off the pp region, an order of magnitude short of what the Standard Solar Model already predicts.
Assessment of Super- and Hyper-Kamiokande Sensitivity to the DSNB
Sensitivity of SK and HK to the diffuse supernova neutrino background, built on published SK results: ten more years of SK stays modest, HK can reach a statistically significant discovery. The methodological point is the one that matters here — atmospheric backgrounds have to be treated with correct oscillations and propagation, otherwise both the sensitivity and the extracted flux come out wrong.
Matter Swapping between Two Branes: A Local Type IIB D3-D7-D3 Realization of Charged-Fermion Mixing via E3 Instantons
A local Type IIB D3$_+$-D7-D3$_-$/E3 construction where interbrane fermion mixing is perturbatively forbidden and generated by E3 instantons, D7 Wilson transport supplying the gauge-invariant relative connection. The interest is the claim of computability: in a complete compactification the mixing parameter would follow from microscopic string data, which is the same ambition as deriving flavour from the compactification.
Void probability function in the Quijote simulations
Void probability function across the Quijote suite: the halo VPF follows the geometric hierarchical model at $z=0$ with $\Lambda$CDM deviating least and the massive-neutrino cosmology deviating most. If that ordering survives realistic dilution and cosmic variance, the VPF is a cheap additional handle on $\sum m_\nu$ from void statistics rather than the power spectrum.
On the singularities and the Kodaira dimension of unitary Shimura varieties
Toroidal compactifications of unitary Shimura varieties of signature $(p,q)$ with at worst canonical singularities, and finiteness of the pairs that are not of general type. Modular flavour symmetry with several moduli lives on exactly these higher-dimensional Hermitian domains, and the geometry of the compactified boundary is what controls which automorphic forms are available near a cusp.
Effective Hecke eigenvalue equidistribution over the Atkin--Lehner subspaces
Effective equidistribution of Hecke eigenvalues over Atkin--Lehner subspaces, with explicit bounds. The Atkin--Lehner (Fricke) involutions are the extension of $\Gamma_0(N)$ that modular flavour models invoke when they enlarge the modular group, and this is a quantitative statement about how forms distribute between the resulting eigenspaces.

arXiv digest — 2026-09-16

Wed, 16 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-16 — neutrino physics, flavour symmetries and astroparticle physics.

Vanilla Scotogenic Model at the future Muon Collider
Scotogenic radiative neutrino mass with three right-handed neutrinos and an inert doublet, with enhanced second-generation Yukawas pulling the leptogenesis scale down to $\sim 1$ TeV. The charged scalar then comes out long-lived, so the handle is displaced vertices rather than mono-photons: a concrete collider test of a low-scale neutrino-mass-plus-leptogenesis construction.
Making the Great Desert Bloom
Takes the great desert — no new physics beyond neutrino masses up to the Planck scale — as the hypothesis and extracts consequences: a semiclassical AdS$_4$ vacuum for the Standard Model with a CFT$_3$ dual, and at least one extra dimension far above the Planck length. The same AdS-instability reasoning whose swampland version is sensitive to the neutrino mass ordering and to the Dirac/Majorana choice.
Eclectic flavour symmetries without flavons
Eclectic groups realised as flavour symmetries with no flavons at all: $\Omega(1)$ appears as a finite image of the integral Jacobi group, the semidirect product of $H(\mathbb{Z})$ with $SL(2,\mathbb{Z})$ acting on two moduli $(\tau,z)$, with the Heisenberg factor supplying $\Delta(27)$. Two moduli replace the flavon sector, CP is imposed at the Lagrangian level and broken spontaneously, and the $T^2/\mathbb{Z}_N$ building blocks are sorted out.
Topological Modular Forms Constrain Threshold States in Extremal $\mathcal{N}=1$ AdS$_3$ Gravity
Topological modular forms used as a spectral constraint: assuming the expected tmf divisibility of the Ramond Witten index forces an odd number of Neveu-Schwarz primaries at the BTZ threshold for infinitely many $c=12n$, killing the strict extremal ansatz for that family. Divisibility and congruence properties of modular forms doing physical work, which is the toolbox modular flavour models draw on.
Stringy Gauge Structures
A field-theory action encoding heterotic gauge symmetry enhancement and breaking at special points of toroidal moduli space, kept background-independent through doubled coordinates and a non-commutative product, with the enhanced algebra recovered by rotating the Cartan basis. Enhancement at special moduli is the same mechanism behind flavour symmetry enhancement in heterotic orbifold constructions.
An effective topology-transfer nuisance for Genie-based neutrino-argon semi-inclusive analyses: a methodological proposal with MicroBooNE-constrained diagnostic
LArTPC oscillation analyses split samples at the $\sim 35$ MeV proton tracking threshold, and GENIE Reweight has no dial that moves events across that boundary. A single empirical nuisance $f_{\rm mig}$, constrained to $0.093 \pm 0.024$ on the MicroBooNE CC 0p/Np release, absorbs near-threshold proton mismodelling that otherwise propagates untracked into oscillation systematics.
Probing the Tau Neutrino Magnetic Moment via the $μ^{-}γ\rightarrow μ^{-}ν\barν$ Process at Future Muon Colliders
Model-independent EFT sensitivity to the $\nu_\tau$ anomalous magnetic moment through $\mu^-\gamma \to \mu^-\nu\bar\nu$ at 3, 10 and 30 TeV muon colliders, reaching $\mu_{\tau\tau} = 5.21\times 10^{-8}\,\mu_B$ and improving the DONUT bound by an order of magnitude. Neutrino electromagnetic moments are where the Dirac/Majorana distinction surfaces as transition moments.
Supernova nucleosynthesis: a review
Review of yields across the Type Ia, core-collapse, electron-capture and pair-instability channels. The part that matters here is the neutrino-rich explosion environment setting the $n/p$ ratio: the $\nu$-process and the neutrino-driven wind are where flavour conversion feeds straight into the predicted abundances.
Multiple-Mediator-Affected Ultra-High-Energy Neutrino Attenuation: Hints for 5D ${U(1)}_{L_μ- L_τ}$ in IceCube
Gauged $U(1)_{L_\mu - L_\tau}$ promoted to five dimensions: the Kaluza-Klein tower of mediators produces multiple closely spaced resonances in scattering off the C$\nu$B, with interference and off-resonant $t$- and $u$-channel terms shaping the attenuation. A flavoured gauge symmetry plus an extra dimension, fitted to the soft UHE spectrum IceCube reports.
Modeling Gamma-Ray Bursts Using CRISP
Neutrino spectra from photohadronic interactions in a gamma-ray burst emission region, computed with the nuclear cascades of heavy primaries rather than a proton-only source. Given the heavy composition Auger measures, photodisintegration in the source changes both the normalisation and the shape of the predicted UHE neutrino flux.
Taking dimuon production in DIS to NNLO precision
Dimuon production in neutrino-nucleus DIS computed directly at NNLO from the new SIDIS coefficients, instead of inclusive charm times corrective factors. Scale uncertainties shrink at large $x$ and the cross section falls at small $x$, which may relieve the standing tension between dimuon and LHC gauge-boson constraints on the strange sea.
A general decay form and absolute nuclear stability
Replaces the phenomenological definition of a stable nucleus with a criterion resting on conservation laws alone, yielding 84 absolutely stable nuclei and a ranking of isotopes by decay accessibility. It includes a systematic identification of candidates for natural two-neutrino double-beta decay, which is the background channel every $0\nu\beta\beta$ isotope choice has to live with.
Classification of c=1 CFTs
A complete classification of unitary $c=1$ CFTs with discrete spectrum — the compact boson, its $\mathbb{Z}_2$ orbifold and three orbifolds of SU(2)$_1$ — obtained by recasting the modular bootstrap as a crystalline measure problem and solving it analytically. Orbifolding plus modular invariance pinned down exactly, in a setting where both words carry their flavour-model meaning.
Equivariant Cohomological Crepant Resolution Conjecture for ADE-orbifolds
Equivariant quantum cohomology of the minimal resolution matched to the Chen-Ruan cohomology of $[\mathbb{C}^2/G]$ for every finite $G \subset SL_2(\mathbb{C})$, proved through the McKay correspondence, ADE root systems and character theory, with $E_6, E_7, E_8$ done by exact computation over cyclotomic fields. The finite-group representation theory flavour models run on, applied to the geometry of the orbifold itself.

arXiv digest — 2026-09-15

Tue, 15 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-15 — neutrino physics, flavour symmetries and astroparticle physics.

Less isn't more: Cosmological bounds on the neutrino masses are robust to changes in the neutrino abundance
The standard escape route from the cosmological mass bound — dilute the relic neutrinos by injecting photons after decoupling — does not work. Planck+ACT lensing+DESI give $\sum m_\nu<0.0710$ eV even when dark radiation comes along, and $T_\nu$ turns out to correlate positively with $\sum m_\nu$, so lowering the pre-recombination radiation density sharpens rather than relieves the tension with the measured splittings.
Consistent treatment of flavour-specific neutrino self-interactions in cosmology
Starts from the neutrino quantum kinetic equations and derives the Boltzmann hierarchies in the mass basis, so mixing is carried through consistently instead of being assumed away. The payoff is a clean rescaling of existing CMB limits on the effective self-coupling: weaker by $\sqrt{2}$ when two flavours interact, by $\sqrt{6}$ when only one does, with $\nu_e$-only the one case where the fluid approximation degrades.
Probing Neutrinophilic Scalars in Muon Decays
Muon decay as a laboratory probe of neutrino self-interactions. The phenomenologically live channels — the one-loop correction to SM muon decay and the four-body $\mu^-\to e^-\nu\nu\phi$ modes — are both driven by the coupling $h_{e\mu}$ to Majorana neutrinos, and their infrared divergences cancel against each other. $G_F$ precision alone then gives $|h_{e\mu}|\lesssim0.027$, beating astrophysical and cosmological bounds for $m_\phi\gtrsim\mathcal{O}(\mathrm{GeV})$.
Inelastic Dark Matter at LZ from Radiative Dirac Neutrino Mass Paradigm
A $\mathcal{Z}_2\times\mathcal{Z}_4$ structure that forbids the tree-level Dirac Yukawa and every renormalizable Majorana mass term, leaving neutrino mass Dirac and generated at one loop by a softly broken trilinear $\kappa$. The same $\kappa$ sets the singlet-doublet mixing, so the LZ inelastic rate and $m_\nu$ vanish together; the $Z$ coupling is purely off-diagonal by construction rather than by tuning.
Measurement of $\mathrm{^{75}As}(\mathrm{n},\gamma)\mathrm{^{76}As}$ reaction relevant to 0$\nu\beta\beta$ decay searches of $\mathrm{^{76}Ge}$ and astrophysical $s$-process temperatures
Neutron capture on $^{75}$As from 1 eV to 1 MeV measured by time-of-flight at CSNS Back-n: nineteen resonance structures seen for the first time and disagreements between evaluated libraries resolved. This is experimental input to the background and half-life modelling that $^{76}$Ge $0\nu\beta\beta$ searches depend on, on the nuclear-data side rather than the matrix-element side.
Explain the LZ High-Energy Recoil Event with Inelastic Sneutrino Dark Matter in Supersymmetry
Inelastic sneutrino dark matter in the inverse-seesaw extension of the NMSSM: approximate lepton-number conservation protects the small mass splitting while the left-handed admixture supplies the inelastic signal. The three-generation completion still reproduces the oscillation observables — an example of the inverse-seesaw sector being used as a model-building resource rather than only as a mass mechanism.
Predictive Non-Minimal SU(5) GUT
Replacing the Georgi-Glashow $24$ with a $75$ fixes gauge-coupling unification outright, with no extra matter invoked for that purpose, and pins the unification scale to $10^{15}\,\mathrm{GeV} \lesssim m_{\rm GUT} \lesssim 10^{16}\,\mathrm{GeV}$ — a window Super-Kamiokande already bites into and Hyper-K will close. The $75$ then admits a unique vectorlike $10_F+\overline{10}_F$ to repair the down-quark/charged-lepton relation, so the fermion sector is far more constrained than in the $24$ case.
Measuring the spatio-temporal variation of fundamental physical constants using the OH sum rules
Constrains $\Delta X/X=(-1.8\pm5.1)\times10^{-6}$ with $X=\mu^{-1}\alpha^{2}g_{p}^{0.54}$ from the four OH ground-state lines toward G035.1+0.5. That combination is exactly the one a unified variation of the gauge and Yukawa sectors at the GUT scale predicts, and the sum-rule method avoids spectral profile fitting, so it survives RFI and scales to SKA volumes.
Probe of Solar Neutrino Magnetic Moments through Spin-Flavor Precession: Resonance Structure and Antineutrino Appearance
Solar spin-flavor precession worked out in the full three-active-flavor $6\times6$ Hamiltonian, with the Majorana/Dirac distinction made operational: Majorana transition moments give a lepton-number-violating solar $\bar\nu_e$ signal, Dirac moments only sterile right-handed states and disappearance. No finite-density Majorana crossing survives for normal ordering, but the nonresonant conversion still puts Jinping at $|\mu_{12}|\simeq(2.3-4.1)\times10^{-13}\,\mu_B$, below direct-scattering and stellar-cooling bounds.
Probing Neutrino-Energy Reconstruction with New Superscaling-Based Observables
Reparametrizes the superscaling variable $\psi'$ directly in terms of the neutrino-energy reconstruction bias, then expands around the quasielastic point to produce observables built only from outgoing-muon kinematics. The new $L_1$ still separates NEUT, NuWro and GENIE nuclear models across carbon and argon targets — useful if you care how the CCQE model choice propagates into an oscillation fit.
Comment for the SCAC Facilities Subcommittee from the Division of Particles and Fields of the American Physical Society
The Division of Particles and Fields' formal input to the SCAC facilities subpanel on DUNE Phase II detectors and U.S. contributions to a future Higgs factory, framed against P5. Short and non-technical, but this is the kind of document that gets cited when the scope of the long-baseline program's second phase is decided.
Neutron Skin Effects on Particle Emission in Heavy-Ion Collisions: A Topic Review with Astrophysical and Nuclear Structure Connections
A review of how the neutron skin propagates into heavy-ion emission observables and the density dependence of the symmetry energy. The relevant hook is the section tying it to parity-violating electron scattering and coherent elastic neutrino-nucleus scattering: the same isovector density profile controls the CE$\nu$NS form-factor systematics that limit NSI extractions.
Invariant Algebras of Low-Rank Neutrino Matter Flows: Krylov-Pl\"ucker Invariants, the $3+1$ Toric Ring, and Controlled Deformations
Matter potentials and off-diagonal NSI enter the flavor-basis Hamiltonian as a low-rank additive deformation, and this constructs the full ring of quantities insensitive to it — with an exact dimension formula for arbitrary flavor number. The sharp statement for $3+1$: the eleven invariants in common use are a generic local coordinate system, not a global polynomial generating set, the global object being the toric cycle ring of the four-vertex flavor graph.
Two-term dilogarithms, mixed-base Nahm sums, and Fricke symmetry
Fricke transformations are the same objects that stabilize the modulus at the self-dual point in modular flavor models; here they organize two-term Rogers dilogarithm identities for rank-two Nahm sums, and the cusp growth of the index-13 system reproduces the saddle action with all three leading Fricke amplitudes exact.
Level structures on tropical abelian varieties
Level-$m$ structures on principally polarized abelian varieties are the congruence subgroups whose quotients give the finite modular flavor groups $\Gamma_N$. Seeing the tropicalization $A_2[m]^{\rm trop}$ computed explicitly — a wedge of orientable surfaces and circles, with genera counted — is a concrete picture of what level structure does near the cusp.

arXiv digest — 2026-09-14

Mon, 14 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-14 — neutrino physics, flavour symmetries and astroparticle physics.

Leptogenesis Determined By Low Energy Parameters
Fixing $m_D$ to the up-quark, down-quark or charged-lepton mass matrix — the GUT-inspired ansatze — closes the type-I seesaw and makes $M_R$ reconstructible from low-energy data alone. Successful leptogenesis survives only for normal ordering with nonzero Majorana phases, and forces $|M_i-M_j|/M_i < 10^{-3}$ while staying outside the resonant regime; $m_{\beta\beta}$ lands within reach of sub-10 meV experiments.
Muon decay across scales: from LEFT to SMEFT
The total rate and the Michel parameters mapped onto dimension-five and -six LEFT operators with arbitrary neutrino flavor assignments, lepton-number-violating operators included. The line that matters here: along the LNV directions, neutrino-mass constraints from operator mixing are more restrictive than muon decay itself.
Can a minimal radiative seesaw explain the LZ 248 keV event?
The Scotogenic model asked to do two jobs at once: inelastic dark matter for the LZ 248 keV recoil, and neutrino mass at one loop. A hidden $U(1)_X$ generates the tiny $\lambda_5$ radiatively and makes the scattering isospin-violating, which is what relieves the tension with IceCube limits on solar capture.
Simple Modular $S_3$ Models for Lepton Masses and Mixing
A complete classification of modular $S_3$ lepton models with no flavons, no right-handed neutrinos and no enlarged gauge symmetry — the minimal end of the modular-flavor program. Bayesian comparison across the admissible weight assignments leaves 18 viable models for NO and 19 for IO, with the predicted $m_\beta$ ranges completely disjoint between the two orderings.
Demonstrating topological identification capabilities of the NEXT experiment at low pressure
First topological validation of NEXT-100 from the Canfranc run at ~4 bar: 75.6% efficiency on double-electron tracks against 14.7% acceptance for $^{208}$Tl single electrons. This is the baseline number that decides how far high-pressure xenon can push $m_{\beta\beta}$ in the next generation.
Probing Neutrinophilic Axion-Like Particles in Tritium Beta Decay
Spectral distortions of the tritium endpoint from keV-scale neutrinophilic ALPs, for both lepton-number-conserving and lepton-number-violating couplings, with KATRIN and TRISTAN sensitivities. The interesting half is the construction that evades the cosmological bounds through a non-trivial thermal history — that is what decides whether direct-mass experiments lead here at all.
Minimal Flavoured DFSZ Axion Models: Predictive Yukawa Textures and Flavour Constraints
A fully horizontal Peccei-Quinn symmetry doing the work of a family symmetry, with domain wall number one and texture-zero quark mass matrices. The entire quark Yukawa sector is reconstructed from measured masses and CKM parameters, so the flavor-violating Higgs and axion couplings come out as predictions rather than as free parameters.
Projective Kernels and Replicability in Modular Function Theory
One two-point kernel tying together Schwarzian invariants, Faber-Grunsky data and modular correspondences, extended to the arithmetic Hecke triangle groups. Hauptmoduln and their Schwarzian equations are the same genus-zero objects that fix the modular-form bases used in flavor model building.
Searches for Non-Standard Neutrino Oscillations with the IceCube Neutrino Observatory
A thesis-length treatment of the unstable-$\nu_4$ escape route from the 3+1 tension: 10.67 yr of high-energy atmospheric data exclude most of the short-baseline-preferred region at 90% CL. It also carries new $\nu$-nucleon and $\nu$-nucleus DIS cross sections and the groundwork for a resonant antineutrino-disappearance search.
Supernova cooling from neutrinophilic dark matter
Dark matter produced by $\nu\nu$ scattering inside a core-collapse supernova, bounded by the cooling argument: more than ten orders of magnitude beyond indirect detection below $\mathcal{O}(100)$ MeV. The effective $\nu$-DM operators constrained here are the same ones that parameterize secret neutrino interactions.
Electromagnetic Probes of the Supernova Engine
A review of what shock breakout, light curves and remnants say about the explosion engine — the electromagnetic half of the argument whose other half is the neutrino burst. Useful for calibrating what a Galactic supernova would actually pin down about neutrino physics, oscillations included.
Probing Lorentz Invariance Violation in Cosmogenic Neutrino Propagation with KM3-230213A
Superluminal LIV reshapes the cosmogenic flux — suppression at the top of the spectrum, a pile-up at PeV-EeV — and KM3-230213A sits where the effect is largest. Sensitivity peaks for $10^{-24}\,\mathrm{eV}^{-1} \lesssim \delta_{\nu,1} \lesssim 10^{-22}\,\mathrm{eV}^{-1}$, the regime where propagation over cosmological baselines outruns terrestrial oscillation tests.
Time-Integrated Searches for Sub-TeV Neutrino Sources with IceCube-DeepCore
DeepCore pushed down to 30-400 GeV over 11.1 yr, with a per-flavor limit on NGC 1068 only a factor of two above the extrapolation from higher energies. The soft-spectrum window is where source physics and atmospheric-oscillation systematics share the same energy range.
Zeros of Quasimodular Forms Defined by Iterated Sums
Quasimodular forms are what appear the moment $E_2$ enters a modular-invariant construction, and where their zeros sit in the fundamental domain is where the corresponding couplings vanish. Here: exactly $n$ simple zeros on each of $\Re\tau = 0$ and $1/2$, interlacing in $n$, and all of them transcendental.
Eta-Quotient Representations for a Three Parameter Family of Modular Functions Associated with the Rogers-Ramanujan Continued Fraction
Eta quotients are the working representation of level-$N$ modular forms in flavor model building, and a recursion that generates a whole three-parameter family is exactly the machinery one wants when scanning modular weights. The application here is to partition dissections, but the construction travels.

arXiv digest — 2026-09-11

Fri, 11 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-11 — neutrino physics, flavour symmetries and astroparticle physics.

The Dark Dimension and Majorana Neutrinos
Bulk Majorana fermions in a Swampland-motivated micron-scale extra dimension, confronted with Daya Bay, KATRIN and KamLAND-Zen. The useful result is structural: the Kaluza-Klein tower screens $0\nu\beta\beta$ once the nuclear momentum exceeds both the compactification and Majorana scales, so the effective mass is suppressed while beta decay is not. Oscillations and $0\nu\beta\beta$ then probe opposite ends of the Majorana mass range, and $\beta$ decay drives the Yukawas to $\mathcal{O}(10^{-3})$.
Chiral Spin(7) Sigma Models and Topological Modular Forms
Chiral $\mathcal{N}=(0,1)$ sigma models on Spin(7) manifolds, with the Spin(7) structure fixing the left-moving fermion bundle so that internal anomalies cancel and one right-moving Majorana-Weyl fermion is left over. The obstruction class lives in the torsion of topological modular forms and is nonzero exactly when the target's Euler characteristic is odd — and the whole diagonal Joyce orbifold family (coordinate reflections and half-shifts) has even orbifold Euler characteristic, hence a vanishing class. Modular forms as an anomaly obstruction on orbifold compactifications.
F-theory on K3 surfaces and orthogonal modular forms
Identifies the F-theory duals of the heterotic string on $T^2$ with general Wilson lines in one $E_8$, writing the elliptic curve in terms of orthogonal modular forms and fixing it by demanding a scaling limit to a rational elliptic surface (the E-string Seiberg-Witten curve). Conjecturally an explicit inverse period map for $U\oplus E_8(-1)$-polarized K3s. Orthogonal modular forms on the Wilson-line moduli space are the higher-rank generalization of the $SL(2,\mathbb{Z})$ forms that carry flavor structure.
Landau-Ginzburg description of an exceptional ${\mathcal N}=1$ minimal model
A Landau-Ginzburg description of the $m=12$ $\mathcal{N}=1$ superconformal minimal model with the exceptional $(E_6,D_8)$ modular invariant, via two real superfields with a cubic superpotential. The fusion ring is extracted from the modular data of the extended algebra and carries a $\mathbb{Z}_2$ grading by chiral fermion parity that the fusion coefficients alone miss — that grading becomes the R-parity of the LG theory. Modular data fixing a discrete symmetry that the naive algebra does not see.
Rank-one 4d $\mathcal N=3$ SCFTs: Schur index, VOA modules, and modularity
Schur indices of rank-one 4d $\mathcal{N}=3$ S-fold theories in closed form via Dedekind eta functions, with the non-vacuum characters solving a modular linear differential equation whose solution space also contains a logarithmic character. Flavored MLDEs plus Zhu's algebra and a free-field realization fix four highest-weight modules. The MLDE/vector-valued-modular-form machinery here is the same technology that classifies finite modular quotients and their weight-$k$ multiplets.
The NOvA Test Beam Experiment
The dedicated NOvA test-beam run at FNAL: a 30-ton slice functionally identical to the Near and Far Detectors, exposed to tagged $e$, $\mu$, $\pi$, $K$, $p$ at 0.4-1.5 GeV/c. This is where the detector response, energy calibration and hadronic/electromagnetic resolution uncertainties — the dominant systematics on NOvA's mass-ordering and $\delta_{CP}$ contours — actually get pinned down. Worth reading as the provenance of the error budget behind the oscillation fits you use.
Might the radiation era extend back to the Big Bang? On dark matter production and the relic graviton background in quadratic gravity
In quadratic gravity the radiation era can be extended back to the bang without overproducing dark matter, and the price is a relation between the Weyl coefficient $f_2$ and the dark matter mass. The relevant point for you is that stable right-handed neutrinos are the quoted candidate: a purely gravitational production mechanism for sterile states, with the relic graviton background showing up in $N_{\rm eff}$ as the observational handle.
IceCube neutrino point-source searches in the direction of the KM3NeT ultra-high-energy event
Fifteen years of IceCube data toward KM3-230213A, tested as steady, time-coincident flaring, or untriggered. Nothing. The resulting point-source limits sit below the flux implied by the single KM3NeT event for a range of spectral indices around 2.0, which strongly constrains any steady or transient astrophysical source interpretation — and correspondingly strengthens the exotic-origin scenarios.
Solar Neutrino Constraints on Inelastic Dark Matter Scattering in Light of Recent LUX-ZEPLIN Observations
The LZ high-recoil candidate has revived momentum-dependent and inelastic dark matter. Here the constraint comes from the other side: inelastic scattering also captures dark matter in the Sun, and IceCube sees no excess of high-energy solar neutrinos. The absence confirms Pospelov-Ramani and cuts deep into the parameter space that the LZ event would otherwise favor.
Cosmological Evolution of Primordial Black Holes: UV/IR Decoupling and the KM3NeT 220 PeV Neutrino Anomaly
Embeds an evaporating primordial black hole in a McVittie background, so cosmological accretion and expansion-suppressed Hawking emission shift the initial mass window for a terminal burst today. The final explosion is still governed by Schwarzschild thermodynamics, which is what lets the 220 PeV KM3NeT event be produced locally without violating the diffuse isotropic limits. Read together with the IceCube non-detection below.
Inelastic Dark Matter and High-Energy Recoil Signatures in LZ
The complementary reading of the same LZ event: two-component inelastic dark matter, where the exothermic branch produces high-recoil signals without relying on the tail of the velocity distribution. The required cross section drops enough to relax the IceCube solar-neutrino bound — which is precisely the constraint the previous paper tightens, so the two together bracket how much room the scenario really has.
Non-invertible Selection Rules from Generalized Discrete Gauging of Finite Non-Abelian Symmetries
Selection rules for theories where a discrete flavor group $G$ is gauged by a subgroup $H$, worked out for exactly your groups: $\Delta(54)\cong\Delta(27)\rtimes\mathbb{Z}_2$ and $S_4\cong A_4\rtimes\mathbb{Z}_2$. The point is that the $H$ action mixes components inside $G$-multiplets, so Clebsch-Gordan decomposition of tensor products no longer tells you which couplings survive — you need their projected characters. That changes the allowed superpotential terms and forces relations among couplings in any model built on these groups. The paper of the day for you.
The $E_6$ Restricted Hyperplane Arrangement and its $E_7$ Shadow: Weyl Transport on a Minuscule Bruhat Poset
The fan cut in the $E_6$ dual Weyl chamber by the weights of the $\mathbf{27}$: only 11 of the 27 weights matter, 14 simplicial chambers, and a 14-element subposet of the $E_7$ $\mathbf{56}$ whose Hasse diagram is the chamber adjacency graph. The three $7+7$ splittings of types $A_7$, $D_7$, $E_7$ are Levi-center $\mathfrak{u}(1)$-charge decompositions of the $\mathbf{56}$ — i.e. the combinatorics underlying the $E_7\supset E_6\times U(1)$ breaking chains and the $\mathbf{27}$ matter assignments of $E_6$ unification.
Reversibility and its asymptotic counting in Picard group
Reversible and strongly reversible elements of the Picard modular group $\mathrm{PSL}(2,\mathbb{Z}[i])$, classified up to conjugacy with eight distinguished representatives per loxodromic class, plus a bounded-trace asymptotic count. $\mathbb{Z}[i]$ is where modular flavor symmetry goes when the modulus stops being a single $\tau$ — the conjugacy structure is what a finite quotient would inherit.
Cusp restrictions and Bunke--Naumann invariants with level structure
Weakly holomorphic level-one modular forms of weight divisible by four, imported into stable homotopy, vanish at every nontrivial $\Gamma_0(N)$ level, with a weight-two correction restoring an integral global class. An unexpected place to see the level-raising structure of $\Gamma_0(N)$ — the same congruence subgroups whose finite quotients $\Gamma_N$ give $S_3$, $A_4$, $S_4$, $A_5$ — doing real work.

arXiv digest — 2026-09-10

Thu, 10 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-10 — neutrino physics, flavour symmetries and astroparticle physics.

Search for neutrinoless quadruple beta decay of $^{136}$Xe in PandaX-4T detector
Neutrinoless quadruple beta decay is the cleanest experimental handle on Dirac neutrinos: a $0\nu4\beta$ signal without $0\nu2\beta$ would indicate a residual $Z_4$ lepton number rather than Majorana masses. PandaX-4T sets the strongest xenon limit, $6.0\times10^{24}$ yr on $^{136}$Xe, on a channel that Dirac-preserving model classes genuinely predict.
Level-Four Modular Symmetry Selected by the Harmonic Pattern of Quark and Lepton Masses
Reads the logarithmic generation steps of the quark and charged-lepton mass ratios as charge counting on a $Z_N$ clock and finds level four uniquely selected, hence modular $S_4$ with the generations in a triplet at $T$-charges $(3,1,0)$. Weight-$1/2$ theta constants then close the CKM matrix with no continuous parameter, and carry over to the neutrinos: $\sin\theta_{13}=\theta_2(\tau)m_2/m_3$, $\Sigma m_\nu=0.0589$ eV, $\delta_{CP}=\pi$, $m_{\beta\beta}$ of a few meV, with a magnetized-torus UV completion and Pati-Salam embedding. The paper of the day for you.
NOvA Dual-Baseline Search for Active-to-Sterile Neutrino Oscillations using Neutrino- and Antineutrino-Enriched Samples
First NOvA $3+1$ search to fit neutrino- and antineutrino-mode beams simultaneously in both detectors. No sterile signal, and it excludes most of the region IceCube had allowed. Directly constrains eV-scale singlets and the low-scale seesaw variants that park a light sterile state in the accessible range.
Neutrino mass, scalar dark matter, and collider signatures in a radiative doublet-triplet model
One-loop completion of the Weinberg operator (topology T4-3-i) with an inert doublet, a real scalar triplet, a Majorana fermion triplet and a Dirac singlet, with an exact $Z_2$ forbidding the tree-level type-III term. The mass matrix is rank two, so one neutrino stays massless; inverted ordering pushes $m_{\beta\beta}$, $m_\beta$ and $\sum_i m_i$ up, making that branch falsifiable by next-generation $0\nu\beta\beta$ and beta-endpoint experiments.
A Warped Extra Dimensional Candidate for the LZ 248 keV Event
Inelastic dark matter in a Randall-Sundrum geometry where the Majorana mass originates on the UV brane and the TeV-brane Dirac masses are exponentially warped down, so a splitting of order $10^{-7}$ of the Dirac mass comes out without tuning — as does the neutrino-to-quark coupling ratio of the KK $Z'$. The warped mechanism for parametrically small Majorana masses is the transferable part.
Quantum geometric signatures in neutrino dynamics around a holonomy black hole
Three-flavor oscillations in an effective holonomy-corrected Schwarzschild metric: the cross-path phase acquires a logarithmic holonomy contribution and retains information about the absolute neutrino mass scale, with trajectory-flavor entanglement quantified through I-concurrence. Sensitivity to the mass ordering stays weak in the configurations considered, which the authors state plainly.
Quasi-modularity of symmetric quasi-shuffles
Identifies classes of symmetric quasi-shuffles whose multiple $q$-zeta values exhaust the algebra of level-one quasi-modular forms, plus further classes at finite level. Quasi-modular forms — $E_2$ above all — are exactly what appears once modular flavor constructions leave the strictly holomorphic weight, so a structural description of the ring is worth having.
Unorientable supersymmetric compactifications of M-theory
Type II orbifolds combining a free action on the base with $(-1)^{F_L}$, preserving minimal supersymmetry and lifting to M-theory on smooth unorientable manifolds. A corner of orbifold model building that is rarely enumerated, and relevant if you track which discrete actions on the internal manifold are available to generate a flavor symmetry.
Quantifying Information Hierarchy for Neutrino Oscillation Parameters at JUNO
Quantum and classical Fisher information applied to reactor antineutrinos, tracking how much parameter information survives each step from the oscillating state to the observed events. The solar-sector parameters sit essentially at the statistical optimum, while $\theta_{13}$ and $\Delta m^2_{31}$ are degraded by the measurement strategy and detector response rather than by statistics — a useful way to see where JUNO's sub-percent $\Delta m^2_{31}$ actually comes from.
Can Elastic Neutrino Scattering Account for the LZ230616 Event?
Systematic test of whether coherent elastic neutrino-nucleus scattering can produce the 248 keV LZ recoil — Standard Model and beyond, including exotic neutrino fluxes from dark matter annihilation, dark matter decay and primordial black hole evaporation. It cannot, in any scenario. The kinematic and spectral arguments double as limits on non-standard neutrino-nucleus interactions and on high-energy $\nu$ fluxes from the dark sector.
Hadronic origin of gamma rays and neutrinos from blazars: Multi-messenger implications and observational constraints
Bounds the UHECR luminosity of the four nearest neutrino-bright blazars by requiring the total emission not overshoot multi-wavelength data, then forecasts 50 h CTAO exposures. Cosmogenic gammas stay under $\sim7.5\%$ of the emission at $10^{20}$ eV, so the $10^{44}$–$10^{46}$ erg s$^{-1}$ neutrino output is the robust propagation signature of hadronic acceleration.
Anomalies at the End of the Universe?
Anomalies localized in the IR of an AdS slice fail to match across geometries dual to different states of the same CFT unless topological terms or extra bulk fermions flow them into the UV region. The same bookkeeping governs anomaly localization at orbifold fixed points, where it decides which matter content a GUT construction is allowed to put on a brane.
An elementary approach to Sun Kim's general theta function identities
Elementary $q$-series proofs of Kim's general theta function identities, the ones behind Ramanujan's modular equations of degrees 5, 11 and 23. The weight-$1/2$ theta constants that carry the mass hierarchy in today's level-four paper are the same objects — this tells you which identities among them are genuinely independent.
Constant Maps and Exponentially Small Sectors in ABJM Bethe Observables
A divisor-sum formula with a conjectural all-order Eichler-integral series attached to a weight-four Eisenstein form, plus modular-product formulas, falls out of the finite-rank ABJM twisted index. The modular machinery of flavor model building keeps turning up as the arithmetic skeleton of exact results in unrelated corners of the field.

arXiv digest — 2026-09-08

Tue, 08 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-08 — neutrino physics, flavour symmetries and astroparticle physics.

Displaced Signals from Long-lived Particles in Neutrinoless Double Beta Decay
A Majoron-like $\phi$ produced on-shell in $0\nu\beta\beta$ and decaying to $\gamma\gamma$, $\gamma\gamma_D$ or $e^+e^-$ after a macroscopic flight reshapes the visible energy spectrum instead of vanishing as missing energy. Claimed gain of more than two orders of magnitude over standard invisible-Majoron searches — directly relevant to spontaneously broken lepton number.
Flavor Tomography of Long-Lived Neutrino-Mass Mediators: Probing the Neutrino Mass Ordering at the HL-LHC
If the long-lived particle giving displaced leptons is also the mediator of Majorana masses, Casas–Ibarra fixes the ratio $N_e/N_\mu$ of delayed leptons from PMNS data alone: $0.140$ for normal, $2.11$ for inverted ordering. Identical across scotogenic, type-III, inverse and linear seesaw, and free of $\delta_{CP}$ degeneracy.
Probing $ν$SMEFT at Belle II with displaced dilepton vertices
Belle II reach for GeV-scale HNLs via displaced dilepton vertices, organised in $\nu$SMEFT: four-fermion, Higgs-current and dipole operators. For most operators the proposed search covers parameter space unconstrained elsewhere — a clean map of what remains open for right-handed neutrinos below the electroweak scale.
Light Leptoquarks in a Dark Sector: Scalar Dark Matter, Neutrino Mass, and Collider Signatures
$\mathbb{Z}_2$-odd leptoquarks and vector-like quarks generate Majorana neutrino masses radiatively at one loop while the parity forbids the usual LQ decay into quark plus lepton, so sub-TeV dark LQs evade conventional LHC bounds and co-annihilate with the singlet scalar dark matter. Collider prospects assessed at a future muon collider.
Dark matter glueball candidate from a $G(2)$--$E_6$--$E_7$ exceptional grand unified theory: $G$-parity, spin, mass and stability
Exceptional unification along $G(2)$–$E_6$–$E_7$: gauge-invariant identity, mass scale and UV stability of the dark glueball from $G(2)\to SU(3)_C$. The minimal chiral embedding yields no exact dark $G$-parity through dimension seven; moving the dark Higgs from $\mathbf{1463}_H$ to $\mathbf{1539}_H$ removes the scalar-parent obstruction.
Probing the Geometry of Viable Froggatt-Nielsen-like Flavor Textures
Texture-level scan of a Froggatt–Nielsen toy landscape: eighteen integer exponents cut on quark mass ratios and CKM observables. PCA needs fifteen components for 90% of the variance and TwoNN/Levina–Bickel give intrinsic dimension $10$–$12$ — evidence that raw FN charges are not the natural coordinates for whatever geometry organises flavour.
The groups $\operatorname{SL}_2(\mathbb{F}_{13})$ and $\operatorname{SL}_2(\mathbb{F}_{19})$ are Galois over $\mathbb{Q}$
$\mathrm{SL}_2(\mathbb{F}_{13})$ and $\mathrm{SL}_2(\mathbb{F}_{19})$ realised as Galois groups of totally real extensions of $\mathbb{Q}$, the degree-20 polynomial coming from Yang's modular equations for the Shimura curve $X_6^*(1)$. These are precisely the finite modular groups at levels 13 and 19 — levels modular-flavour model building has never exploited, with explicit arithmetic now available.
Counting level-raising congruences using modular representation theory
Mod-$\ell$ congruences between eigenforms through the modular representation theory of $\mathrm{PGL}_2(\mathbb{F}_p)$: extra structure on spaces of modular forms of level $\Gamma_0(p^2)$ that not only proves level-raising congruences but counts them — without Galois deformation theory, $R=\mathbb{T}$, or Jacquet–Langlands. Level structure is the same object modular flavour models build on.
Self-Interacting Sterile Neutrino Cold Dark Matter: Resonant Production Mechanism in the Early Universe
Sterile-neutrino cold dark matter produced with no appreciable active-sterile mixing: thermal self-energies from the $N_2$ and $\phi$ backgrounds generate a temperature-dependent splitting and off-diagonal mixing, and the in-medium level crossing follows Landau–Zener even under collisional damping. Relic yield $Y_1\propto g_{12}^2 g_{22}M_{\rm Pl}/m_1$, so $\rho_{\rm DM}$ is nearly independent of $m_1$.
Stability of Collective Neutrino Oscillations -- A Distributional Approach
Collective flavour conversion recast as Kuramoto synchronisation: an exact nonlinear Fokker–Planck equation for the one-body distribution on the flavour sphere at $N\to\infty$. The resulting eigenvalue condition governs growth from arbitrary initial distributions, not just states near full flavour coherence — a genuine step past the usual linear stability analysis of collective modes.
Atmospheric neutrino up-scattering explanation of LZ 2026 excess
The isolated $248$ keV LZ recoil read as atmospheric-neutrino up-scattering $\nu\mathcal{N}\to\chi\mathcal{N}$ through a scalar mediator: the kinematic threshold naturally cuts off low recoil energies and so explains why the event sits alone at high energy. Naturally realised in sterile-neutrino models, though the fit is kept generic in $\chi$.
A Differentiable Neural Surrogate for Photon Propagation in Neutrino Telescopes
A differentiable SIREN neural field learning the photon Green's function of IceCube: events generated $50$–$100\times$ faster than Monte Carlo, median yields within $2\%$ and timing at the MC statistical floor. End-to-end gradients open the door to optimising ice scattering properties, which dominate systematics in neutrino telescopes.
TeV Higgsino Interpretation of the LZ High-Recoil Event with Intermediate-Scale Electroweak Gauginos
The non-universal boundary condition $M_1^G/M_2^G=-3/5$ at the $\mathrm{SU}(5)$ GUT scale cancels the leading bino and wino contributions and survives homogeneous one-loop running, producing the sub-MeV Higgsino splitting the LZ event wants. The paper identifies which mixed $\mathrm{SU}(5)$ representations realise that gaugino ratio.
Sgr A* as a Galactic PeVatron: Multimessenger Signatures of the Magnetic Penrose Process
Magnetic Penrose process at Sgr A* in its ultra-high-efficiency regime, with neutron beta decay inside the ergosphere computed from reaction kinematics and Kerr trajectories. Protons reach PeV energies and the hadronic neutrino flux from the Central Molecular Zone, while below IceCube's diffuse Galactic component, is within reach of KM3NeT/ARCA and IceCube-Gen2.
KM3NeT/ARCA stacking search for high-energy neutrino point sources: the case of ultra-luminous infrared galaxies and blazars
Stacking search on 336 days of ARCA data (19–21 detection units, 1544 track candidates) towards ULIRGs, high-synchrotron-peaked BL Lacs and extreme blazars. No significant excess over the atmospheric background; 90% CL upper limits. A first gauge of ARCA point-source sensitivity while the detector is still partially built.
Euclid preparation. The shape of halo profiles in $Λ$CDM and non-standard cosmologies
Imprint of massive neutrinos, $f(\mathcal{R})$ gravity and dynamical dark energy on halo profiles out to $5\,r_{500\rm c}$. Massive neutrinos partly cancel the $f(\mathcal{R})$ signal — free streaming against fifth-force-enhanced growth — and $\sim10^5$ stacked haloes are needed at $z=1.1$. Systematics context for cluster-lensing bounds on $\sum m_\nu$.
Cutting corners: exciting and magical bounds from the cusp bootstrap
Line defects in a rectangular geometry obey bootstrap constraints formally like the spinless modular bootstrap, and the authors exhibit an analytic “magic” functional saturating the bound on the right-angle cusp dimension. The same extremal-functional technology that modular invariance supports, running in a completely different setting.
Open-Closed-Open Triality for 1/2 BPS Three-Point Functions
Connected three-matrix contractions determine three-coloured integer Strebel surfaces described by barycentrically subdivided Belyi maps and Hurwitz constellations — the same arithmetic objects that live on modular curves, here controlling half-BPS three-point functions.

arXiv digest — 2026-09-07

Mon, 07 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-07 — neutrino physics, flavour symmetries and astroparticle physics.

Displaced Signals from Long-lived Particles in Neutrinoless Double Beta Decay
Standard Majoron searches in $0\nu\beta\beta$ assume the emitted scalar leaves as missing energy. Here $\phi$ is produced on-shell and decays visibly to $\gamma\gamma$, $\gamma\gamma_D$ or $e^+e^-$ after a macroscopic flight, reshaping the summed-electron spectrum and adding displaced deposits — more than two orders of magnitude in reach on the Majoron couplings, i.e. on the singlet-Majoron seesaw sector itself.
Counting level-raising congruences using modular representation theory
Level-raising congruences between mod-$\ell$ eigenforms are here counted, not merely shown to exist, via the modular representation theory of $\mathrm{PGL}_2(\mathbb{F}_p)$ acting on $\Gamma_0(p^2)$-level forms — no Eisenstein constant terms, no $R=\mathbb{T}$, no Jacquet–Langlands. The same finite-group-on-modular-forms structure is what finite modular flavour groups $\Gamma_N$ are built from.
New measurements in leptonic kaon and pion decays: experimental and theoretical perspectives
The double ratio $R_{K\pi}^{e}/R_{K\pi}^{\mu}$ pushed to $10^{-4}$, now matched by lattice QCD, is the sharpest test of $e$–$\mu$ universality in charged-current decays with a neutrino in the final state. It is also the channel where heavy-neutral-lepton mixing and lepton-flavour-non-universal operators show up first, so it constrains the charged-lepton side of any leptonic flavour model.
Decompactification and the Flat-Space Limit of AdS$_5\times$ S$^5$ Master Correlators
Resums the entire Kaluza–Klein tower of $S^5$ into single master propagators and correlators, then takes the decompactification limit in one stroke. A clean worked example of a full KK tower — not just its zero mode — controlling the effective theory of a compactification.
Inelastic from the Other Side: Xenon Excitation Signals in Light of the LZ High-Recoil Event
S1–S2 response modelling and isotope-induced background structure for xenon TPCs in the extended-recoil region, calibrated on public LZ data. These are exactly the systematics that will decide how cleanly the solar and atmospheric CE$\nu$NS signal is read out of the neutrino fog.

arXiv digest — 2026-09-04

Fri, 04 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-04 — neutrino physics, flavour symmetries and astroparticle physics.

Light Leptoquarks in a Dark Sector: Scalar Dark Matter, Neutrino Mass, and Collider Signatures
Dark leptoquarks plus vector-like quarks generating Majorana neutrino masses radiatively at one loop, with a $\mathbb{Z}_2$-odd singlet scalar as DM. The $\mathbb{Z}_2$ parity that stabilises the DM is the same one that forbids the standard LQ decays, so sub-TeV coloured states survive LHC bounds. Muon-collider prospects included.
A Peccei--Quinn Origin for Inelastic Electroweak Dark Matter after LUX-ZEPLIN
A PQ-charged singlet fermion gets its Majorana mass from the PQ-breaking VEV and, integrated out, generates the dimension-five operator splitting a vector-like EW doublet. Structurally this is a seesaw run in the dark sector, with $M_N = y_S v_S/\sqrt{2}$ at $v_S \simeq 4.4\times10^{11}$ GeV, and the axion supplies the rest of the relic density.
Quark Mixing Model with Three Higgs Doublets and $S_3$ Modular Symmetry at $τ=i$
Modular $S_3$ with three Higgs doublets, Yukawas evaluated at the fixed point $\tau=i$: the residual symmetry at the fixed point plus the VEV conditions from the scalar potential collapse the parameter count to four, enough to fit $V_{CKM}$ precisely. A clean test of whether modular fixed points are predictive in the quark sector, not just the lepton one.
Probing the Geometry of Viable Froggatt-Nielsen-like Flavor Textures
Meloni asks whether the space of viable Froggatt-Nielsen textures has low-dimensional structure, and answers no: PCA needs fifteen components for 90% of the variance, TwoNN and Levina-Bickel give intrinsic dimension 10-12. The raw charge exponents are bad coordinates. Directly relevant to how one should search flavour-model landscapes at all.
The groups $\operatorname{SL}_2(\mathbb{F}_{13})$ and $\operatorname{SL}_2(\mathbb{F}_{19})$ are Galois over $\mathbb{Q}$
Explicit totally real $\mathbb{Q}$-extensions with Galois group $\mathrm{SL}_2(\mathbb{F}_{13})$ and $\mathrm{SL}_2(\mathbb{F}_{19})$, the degree-20 polynomial obtained from Yang's modular equations for the Shimura curve $X_6^*(1)$. These are exactly the finite modular groups $\Gamma'_N$ at prime level that appear as flavour symmetries; explicit realisations and their modular equations are usable input.
The Klein-Vélu septic, 2-Division, and modular function fields of level 14
The 2-division of the Klein-Velu septic gives a cubic over the function field of $X(7)$ whose splitting field is that of $X(14)$, with the roots written as septic theta functions at $\tau/2,\tau,2\tau$. Level 7 is $\mathrm{PSL}(2,7)$ territory; explicit generators of the level-14 modular function field are the raw material for higher-level modular flavour constructions.
Monstrous parafermionic defects and other non-invertible symmetries in chiral CFTs
Volpato gives a general technique for embedding chiral algebras, then applies it: a sufficient condition for a holomorphic VOA to be self-orbifold under a cyclic symmetry, with the associated duality defect, plus new topological defects in heterotic-on-$T^4$ CFTs. The self-orbifold criterion is the same modular-invariance bookkeeping that controls eclectic flavour groups from heterotic orbifolds.
Yukawa coupling deviations from four-quark interactions
Four-quark operators that avoid first-generation quarks are hard to see directly at the LHC but leak into Higgs-charm and Higgs-bottom couplings. Flavour physics and $t\bar{t}$ production do the constraining; FCC-ee opens more flavour structures. Relevant as a bound on how much Yukawa structure can be non-Standard-Model without showing up in flavour observables.
Atmospheric neutrino up-scattering explanation of LZ 2026 excess
Atmospheric-$\nu$ up-scattering $\nu N \to \chi N$ as the source of the isolated 248 keV LZ recoil. The kinematic threshold explains why nothing appears at lower recoil energy, and the natural UV completion is a sterile-neutrino sector with a scalar mediator. A neutrino-portal reading of the event that competes with the inelastic-DM interpretations dominating the rest of today's listing.
TeV Higgsino Interpretation of the LZ High-Recoil Event with Intermediate-Scale Electroweak Gauginos
The sub-MeV Higgsino splitting needed for LZ is engineered by imposing $M_1^G/M_2^G = -3/5$ at the $\mathrm{SU}(5)$ scale, a ratio that cancels bino and wino contributions and is preserved by one-loop running. The paper identifies which mixed $\mathrm{SU}(5)$ representations realise it: GUT representation content doing real work on a low-energy observable.
Sgr A* as a Galactic PeVatron: Multimessenger Signatures of the Magnetic Penrose Process
Sgr A* as a PeVatron via the magnetic Penrose process, with the neutron production spectrum computed from reaction kinematics and neutron trajectories followed in Kerr spacetime. The resulting neutrino flux sits below the IceCube diffuse Galactic component but the correlated $\gamma$-ray spectral features are the discriminating signature.
KM3NeT/ARCA stacking search for high-energy neutrino point sources: the case of ultra-luminous infrared galaxies and blazars
KM3NeT/ARCA stacking on ULIRGs, HSP BL Lacs and extreme blazars with 336 days and 1544 track candidates: no excess, 90% CL upper limits. Early ARCA sensitivity on the standard source-class hypotheses for the astrophysical diffuse flux, useful as a calibration of where the detector actually is.
Reconstruction of Shower-like Events in NEON Using Likelihood and Graph Neural Network Methods
Shower reconstruction for the proposed NEON deep-sea telescope, comparing a physics-driven MLE (time-residual M-estimator vertex, tabulated photon distributions, PMT angular acceptance, time slewing) against a two-stage GNN. Median angular resolution $4.19^\circ$ and 25-37% energy resolution from 1 TeV to 1 PeV set the baseline for the site.
Euclid preparation. The shape of halo profiles in $Λ$CDM and non-standard cosmologies
Euclid forecast on how massive neutrinos, $f(\mathcal{R})$ gravity and dynamical dark energy deform halo density, mass, velocity-dispersion and excess-surface-density profiles out to $5\,r_{500c}$. Massive neutrinos partially cancel the $f(\mathcal{R})$ enhancement in low-mass haloes: a concrete degeneracy that will limit cluster-WL constraints on $\sum m_\nu$.
Scale-separated AdS$_2$ flux vacua from type II
First AdS$_2$ flux vacua with parametric scale separation, on a $G_2$-structure orbifold times a circle with O1/O5 or O4/O8 planes. Unbounded $F_5$, $H_7$ (IIB) or $F_4$, $F_8$, $H_7$ (IIA) drive the string coupling weak and all internal radii large. Worth tracking for anyone who cares whether orbifold compactifications admit controlled moduli stabilisation.
Confronting the Higgsino Interpretation of the LZ Event with the High-Energy Sideband
The sharpest attack on the higgsino reading of the LZ event: a 1.1 TeV thermal higgsino with a 370-490 keV splitting should also populate the high-energy $S1c$ sideband, where LZ reports nothing. Worth reading alongside the neutrino up-scattering explanation above, since the two make opposite predictions for the sideband.
Lattice QCD calculation of the pion-nucleon coupling $\bar{g}_0$ induced by the QCD $Θ$-term
Lattice extraction of the CP-violating $\bar{g}_0$ from the $\overline{\Theta}$ term, where the honest correlator result is $-7(63)\times10^{-3}$ and only the AWI/EFT route gives $17.4(1.9)\times10^{-3}$. The extended discussion of $N\pi$ excited-state contamination is the transferable part: the same systematic sits underneath lattice $0\nu\beta\beta$ and neutrino-nucleus matrix elements.

arXiv digest — 2026-09-03

Thu, 03 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-03 — neutrino physics, flavour symmetries and astroparticle physics.

Axion Quality from Exact Proton Stability
A discrete anomaly-free $\mathbb{Z}_9$ that survives to the IR and forbids proton decay exactly, obtained by Higgsing a lepton-flavour non-universal $U(1)_X$ that also delivers neutrino masses through a high-scale seesaw. The leftover Goldstone becomes the QCD axion, and the same selection rules push PQ-violating operators to $d\gtrsim10$. Proton stability, seesaw flavour structure and axion quality from one symmetry, with thermal leptogenesis surviving in restricted regions.
Primordial Black Hole Assisted Dirac Leptogenesis
First dedicated treatment of evaporating PBHs inside Dirac leptogenesis, where total lepton number is conserved and the asymmetry is parked in the right-handed neutrino sector. Hawking emission populates the charged-scalar mediator where thermal production fails, pushing the viable mediator mass from $10^9$ down to $10^6$ GeV. The RH neutrinos emitted also feed $\Delta N_{\rm eff}$, landing between Planck and CMB-S4.
Entanglement entropy minimization and global symmetry violation in scatterings
Conjecture that minimizing entanglement entropy in scattering selects the symmetry-preserving point whenever a new interaction opens a symmetry-violating channel — tested on lepton number violation, baryon number violation, LFV and FCNCs. If it holds, the smallness of $\Delta L=2$ operators gets an information-theoretic rationale rather than a symmetry-breaking-scale one.
SN1987A constraints on the neutrino-dark-fermion interaction from resonant scattering with C$ν$B
Supernova neutrinos resonantly annihilating on the C$\nu$B into dark radiation via a light scalar — the same scalar invoked for $\nu$ self-interactions and for neutrino mass generation. The Bayesian analysis makes the central methodological point sharply: SN1987A limits on the $\nu$-scalar coupling are not quotable independently of heavy-flavour emission, flavour conversion, or whether the coupling is mass-proportional.
A Peccei--Quinn Origin for Inelastic Electroweak Dark Matter after LUX-ZEPLIN
Spontaneous PQ breaking leaves a residual parity that both stabilizes the light neutral state and generates the Majorana splitting via a dimension-five operator from an integrated-out PQ-charged singlet — structurally the same operator logic as the Weinberg operator, applied to an EW doublet. The excited state has a $20$ km decay length, giving a luminous signature after terrestrial upscattering.
Quark masses and mixing in the D_5 model under spontaneous CP violation
Systematic scan of all $D_5$ representation assignments for a four-Higgs quark sector with spontaneous CP violation. Only one doublet-plus-singlet assignment survives the non-block-diagonal-CKM and no-massless-quark conditions, and there the $D_5$-constrained vevs force $M_uM_u^\dagger$ and $M_dM_d^\dagger$ to block-diagonalize simultaneously — killing mixing and CP violation. A clean no-go for $D_5$ SCPV, useful as a negative datapoint on small dihedral groups.
Lepton-flavor violation and muon $(g-2)$ in the flavor-dependent $U(1)_F$ model
Muon MDM and $\ell_j\to\ell_i\gamma$, $\ell_j\to3\ell_i$ in an SM extension with a gauged flavour-dependent $U(1)_F$, where the charges are tied to fermion flavour assignments. The continuous-flavour-symmetry analogue of the discrete-group constructions: the induced Yukawas can saturate future MEG-II/Mu3e sensitivity while respecting the current $(g-2)_\mu$ band.
A PQ-Symmetric High-Scale SUSY Interpretation of the LZ High-Energy Recoil
Reads the LZ 248 keV recoil as upscattering of 1.08 TeV thermal Higgsino DM, pushing electroweak gauginos to $\mathcal{O}(10^7)$ GeV within gravity-mediated high-scale SUSY plus a Kim-Nilles PQ sector. The GUT scale comes out lower than the standard one while proton decay is suppressed by the high SUSY scale — the unification-side consequence is what makes this one worth a look.
Fermionic Dark Matter Absorption and the High-Energy Event in LUX-ZEPLIN
Neutral-current absorption of a 247 MeV fermionic DM state on xenon reproduces the monoenergetic 248 keV recoil, but the same operator drives $\chi+{}^{12}\mathrm{C}\to\nu+n+{}^{11}\mathrm{C}^*$. Recasting KamLAND's neutron-emission data excludes the benchmark. A concrete case of a large-volume scintillator neutrino detector arbitrating a xenon signal.
TeV Higgsino Dark Matter from LZ Nuclear Recoil to Fermi-LAT Gamma Rays
Relic abundance fixes 1.1 TeV, the LZ recoil spectrum fixes a few-hundred-keV splitting, and the 10-year IceCube solar-neutrino bound carves the remaining parameter space; the surviving region predicts a Galactic-centre line near H.E.S.S. sensitivity. Same IceCube constraint as arXiv:2609.02775 but used to select rather than exclude — worth reading the two together.
Higgsino Dark Matter Interpretation of the LUX-ZEPLIN 248 keV Nuclear-Recoil Event
Freese and Theodosopoulos take the inelastic Higgsino at face value: two nearly degenerate neutral Majorana states split by $\delta$, with the off-diagonal $Z$ coupling fixing the cross section rather than leaving it free. For $\delta\sim350$ keV the prediction approaches the LZ 90% interval. The minimal-parameter anchor of today's LZ cluster.
Strong Constraints on Higgsino Dark Matter from Solar Capture
Solar gravitational focusing accelerates quasi-Dirac Higgsinos to $\sim1400$ km/s, opening inelastic scattering on heavy nuclei and efficient capture. The annihilation neutrino flux confronted with 10 years of IceCube gives $\delta>566$ keV — a robust neutrino-telescope limit that closes the endothermic-inelastic reading of the LZ event. Textbook example of neutrino astronomy settling a direct-detection claim.
The Hasse norm principle for $A_4$-quartic extensions of global function fields
$A_4$ shows up here as a Galois group rather than a flavour group: the paper counts failures of the Hasse norm principle in $A_4$-quartic extensions of $\mathbb{F}_q(t)$ via a decorated Hurwitz space. A reminder of how much arithmetic structure the group whose triplet you use for tribimaximal mixing carries on its own.
Scale-separated AdS$_2$ flux vacua from type II
First AdS$_2$ flux vacua with parametric scale separation, built on a $G_2$-structure orbifold times a circle with O-planes and unbounded fluxes. Not a flavour construction, but a live demonstration of how much control orbifold compactifications still give over moduli and KK-scale hierarchies — the same technology that underlies eclectic flavour groups.

arXiv digest — 2026-09-02

Wed, 02 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-02 — neutrino physics, flavour symmetries and astroparticle physics.

Proposing GRENDEL: GalleRy ExperimeNt for Decays of Exotic LLPs at the LHC
GRENDEL proposes a scintillator-bar detector in the PX56 gallery above CMS, covering $0.2$-$15$ GeV long-lived particles with 3 ab$^{-1}$. The heavy-neutral-lepton benchmark is the interesting one here: GeV-scale sterile states in the neutrino portal, exactly the mass window where low-scale seesaw and leptogenesis variants live, reached without civil engineering.
Deviation from $μ-τ$ reflection symmetry under radiative corrections in the minimal seesaw framework
Exact $\mu$-$\tau$ reflection symmetry imposed at $\Lambda_{\mu\tau}=10^{14}$ GeV, then run down with the one-loop RGE in the minimal seesaw, where the massless lightest state leaves a single Majorana phase. Analytic low-energy expressions plus the $\tan\beta$ scaling of the breaking give a clean handle on how much of the observed $\theta_{23}$ deviation is radiative rather than structural.
Neutrino masses and mixing angles in the Plan B Model
A gauged $U(1)_{3B_3-L_e-2L_\mu}$ built for $b\to s\ell\ell$ turns out to fix the neutrino sector too: anomaly-cancelling right-handed neutrinos, a Froggatt-Nielsen hierarchy, and a clockwork sector supplying the extra suppression needed to fit oscillation data with $O(1)$ couplings. A concrete test of whether one family-dependent abelian symmetry can carry both the quark and the lepton flavour puzzle.
The Type-I Seesaw as a Relativistic Fermionic Proximity Effect: Spectral Moments, EFT Consistency, and Sterile-Sector Reconstruction
Recasts the type-I seesaw as a proximity effect in the active two-point kernel, with the sterile sector entering through a Nambu-Gorkov embedding self-energy. The moment towers reproduce the Weinberg operator and the dimension-six kinetic term, and Hankel positivity yields matrix Cauchy-Schwarz inequalities linking LNV and LNC data. A genuinely new inverse-problem angle on reconstructing the heavy sector.
SPT-3G D1: Quadratic-Estimator CMB Lensing Reconstruction and Cosmology
SPT-3G D1 lensing at $2\%$ amplitude precision; combined with CMB$_\mathrm{SPA}$ and DESI DR2 BAO it gives $\sum m_\nu < 0.072$ eV at 95% C.L. The bound relaxes relative to earlier work because this lensing measurement sits closer to DESI, which also softens the curvature and $(w_0,w_a)$ preferences. Still squeezes the inverted ordering hard.
Neutrino Experiments at the LHC and the HL-LHC
Status review of FASER and SND@LHC: first collider observation of neutrino interactions, charged-current cross sections, flavour separation, and the HL-LHC outlook. Fills the TeV gap between accelerator beams and atmospheric neutrinos, where the $\nu_e$/$\nu_\tau$ flux is dominated by heavy-flavour decays and cross-section systematics feed straight back into oscillation analyses.
Magnetic field-induced enhancement and quenching of Urca emission in quark matter
Urca neutrino emission from magnetized dense quark matter with Landau quantization of both quarks and electrons. Phase-space restriction produces Shubnikov-de Haas oscillations, resonant spikes, and near-complete quenching above $|eB| \gtrsim 6\mu_e\mu_u$. Directly relevant for compact-star cooling curves and for the anisotropy of the emitted neutrino momentum.
Solar Spin-Dependent Dark Matter-Neutron Cross Section Constraints: The Lost Case
First computation of solar capture and evaporation for spin-dependent dark matter-neutron scattering, using odd-neutron isotopes in the standard solar model. Neutrino and $\gamma$-ray limits beat direct detection for several annihilation channels, and long-lived mediators push the reach below the neutrino fog — a reminder that neutrino telescopes remain competitive DM detectors.
The First Array-Wide Diffuse Flux Search for UHE Neutrinos with the Askaryan Radio Array
First array-wide ARA diffuse search, 2013-2023, with rebuilt noise, antenna-response and lepton-propagation modelling. Either the first in-ice radio UHE candidates or the strongest limits above a few EeV — and either way it fixes the analysis template that RNO-G and IceCube-Gen2 Radio will inherit.
Search for Neutrinos from Tidal Disruption Events with IceCube
Time-dependent and stacked IceCube search over 89 X-ray and optical/UV-selected tidal disruption events, jetted and non-jetted separately. No excess; upper limits on the TDE contribution to the diffuse astrophysical flux under a standard-candle assumption. Narrows the transient-source budget that any explanation of the diffuse spectrum has to respect.
Radiative Corrections and Reheating in Supergravity Models of Inflation
Radiative corrections to Starobinsky-like no-scale supergravity inflation, with the inflaton-matter couplings required for reheating. MSSM-sector corrections are negligible, but Planck data constrain GUT bilinear couplings, vevs and gauge-boson masses directly. A rare case where CMB observables bound the unification-scale superpotential rather than the other way round.
Neutrino Electroweak Couplings and the Neutrino Fog at Belle II
Mono-photon $e^+e^-\to\gamma\nu\bar\nu$ at Belle II reaches $3.6\%$ on the neutrino-sensitive effective weak mixing angle, and polarized beams (Chiral Belle) split neutral- from charged-current contributions, probing the chiral structure of the neutrino gauge couplings independently. Same process sets the neutrino fog for dark-boson searches above 1 ab$^{-1}$.
GRMHD Simulations of Accreting Proto-Magnetars II. Implications for r-process Nucleosynthesis
GRMHD proto-magnetar disks: magnetic channeling and centrifugal acceleration reshape the ejecta composition, and neutrino irradiation is what decides whether the third r-process peak survives. Concrete demonstration that the weak-interaction rates set $Y_e$ in the outflow — the same physics that controls neutrino transport in the collapsar and merger environments.
Fermionic Dark Matter Absorption and the High-Energy Event in LUX-ZEPLIN
The LZ 248 keV event drew three interpretations in a single day; this one dies by a neutrino argument. Recasting KamLAND data on $\chi + {}^{12}\mathrm{C} \to \nu + n + {}^{11}\mathrm{C}^*$ excludes the benchmark, so a large-volume scintillator neutrino detector is what arbitrates a xenon direct-detection anomaly.
Classification of Rational $c=1$ Vertex Operator Algebras and Vertex Operator Superalgebras
Rigorous classification of rational $c=1$ VOAs: everything is a rank-1 lattice algebra $V_L$ or a finite-group orbifold $V_L^G$, with the criterion resting on the vacuum character and congruence-subgroup modularity. The lattice/orbifold/modular-character machinery is the same toolkit that underlies eclectic flavour groups and modular flavour symmetry — worth seeing it used at full rigour.

arXiv digest — 2026-09-01

Tue, 01 Sep 2026 07:00:00 +0000

Curated arXiv digest for 2026-09-01 — neutrino physics, flavour symmetries and astroparticle physics.

SPT-3G D1: Quadratic-Estimator CMB Lensing Reconstruction and Cosmology
SPT-3G D1 lensing plus ACT DR6, Planck PR4 and DESI DR2 BAO gives $\sum m_\nu < 0.072$ eV at 95% CL. That sits below the inverted-ordering floor of $\approx 0.098$ eV, so cosmology keeps squeezing IO from the outside while the $2\%$ lensing-amplitude consistency removes the usual escape route of blaming a $\sigma_8$ anomaly. Worth reading for how much of the bound is BAO-driven.
Symmetric Mass Generation for Domain-Wall Fermions
First lattice test of symmetric mass generation with domain-wall fermions: the four-Fermi term gaps the mirror wall while leaving the physical wall massless, and the gap opens along the imaginary axis of the Dirac spectrum. SMG is the mechanism behind the claim that the SO(10) $\mathbf{16}$ can be gapped without a Higgs condensate, i.e. neutrino mass without a Majorana bilinear — now with numerical support.
Search for proton decay into a single charged antilepton and a massless invisible particle using the full pure water data set of Super-Kamiokande
Super-Kamiokande closes out its pure-water phase on $p\to l^{+}+X$, the decay channel where the recoiling state is a massless invisible singlet rather than a meson. Limits move to $1.72\times10^{33}$ yr ($e^{+}$) and $0.61\times10^{33}$ yr ($\mu^{+}$). These constrain the $B-L$-violating majoron and dark-sector operators that ordinary $p\to e^{+}\pi^{0}$ GUT searches are blind to, so the flavour of the antilepton is the discriminator between operator bases.
An Explicit Belyi Map for the Wiman Sextic and Cusp Forms for a Noncongruence Subgroup
An explicit Belyi map on the Wiman sextic and modular functions for a noncongruence subgroup $\Gamma_{\widetilde W}\subset {\rm SL}_2(\mathbb{Z})$, with a weight-2 unbounded-denominators proof via degeneration over $\mathbb{F}_5$. Modular flavour model building lives almost entirely on congruence subgroups; this is one of the few places where the noncongruence side is made explicit enough to compute with.
$D \to (K π)_{\mathbf{27}}$ at the SU(3)-flavour-symmetric point I: Methodology and strong phase determination
Lattice $D\to(K\pi)_{\mathbf{27}}$ at the SU(3)$_F$ point, isolating a single irrep of the flavour group and extracting the strong phase $\delta_{\mathbf{27}}=-38.4(2.4)^\circ$. Methodologically this is the clean case: representation theory of the flavour symmetry doing the work of separating amplitudes, with the finite-volume matrix elements deferred to part II.
Cascades from ultra-high-energy neutrinos
$\nu$propa extends CRPropa with $\nu\nu$, $\nu\bar\nu$ and $\nu\gamma$ interactions on the C$\nu$B and radiation backgrounds, plus vacuum flavour oscillations. Prompt flux is strongly absorbed above $\sim10^{21}$ eV but secondaries refill the spectrum below. The relevant point for model builders: the flavour composition arriving at Earth is no longer a clean $1{:}1{:}1$ tag of the source.
The First Array-Wide Diffuse Flux Search for UHE Neutrinos with the Askaryan Radio Array
Eleven years of ARA livetime, all five stations combined, for the first array-wide diffuse UHE search. Either the first in-ice radio candidates or the strongest limits above a few EeV. Sets the experimental baseline against which cosmogenic and superheavy-dark-matter neutrino predictions have to be normalised, and fixes the analysis template RNO-G and IceCube-Gen2 Radio will inherit.
Radio measurements of air showers with the IceCube-Gen2 surface prototype station at the Pierre Auger Observatory
Radio air-shower measurements from the IceCube-Gen2 surface prototype at Auger, compared against CoREAS. Mostly a calibration paper, but the surface array is the veto that defines the effective aperture for Southern-sky astrophysical neutrinos in Gen2, so the reconstruction quality shown here propagates into the eventual flux systematics.
TeV Gamma Rays and Neutrinos from Winds Driven by Radiatively Inefficient Accretion Flows of Low-Luminosity Active Galactic Nuclei
TeV emission from NGC 4278 in its quiet state modelled as a shock in a RIAF-driven wind rather than a weak jet, extended to Sgr A*. If LLAGN are a generic population of cosmic-ray accelerators, they contribute a guaranteed diffuse neutrino component that has to be subtracted before any exotic astrophysical-neutrino interpretation survives.
Protected Logical Qudits in Kitaev Quantum Double Models via Stable Representations
Kitaev quantum-double codes built on $A_4$: the $D(A_4)$ representation theory yields a protected logical qutrit and a universal ribbon-based gate set. Same group, same triplet-plus-three-singlets structure you use for lepton mixing, deployed as an error-correcting code — a reminder that $A_4$'s usefulness is about its representation ring, not about flavour.
Quantum Steering Geometry at High Energy Particle Colliders
Quantum steering ellipsoids as collider observables, benchmarked on $t\bar t$ spin density matrices. Dimension-six operators deform the ellipsoid in characteristic ways, so the geometry of conditional states becomes an EFT discriminant — a genuinely different way to read a spin correlation matrix.

arXiv digest — 2026-08-31

Mon, 31 Aug 2026 07:00:00 +0000

Curated arXiv digest for 2026-08-31 — neutrino physics, flavour symmetries and astroparticle physics.

Deciphering Matter Invariants via Renormalization Group Equations for Neutrino Oscillations
Wang and Zhou promote the five algebraically independent matter invariants of three-flavour oscillations to exact first integrals of the matter RGEs, using $S_3$ covariance under mass-eigenstate relabelling and pole-cancellation of the $1/\widetilde\Delta_{ij}$ terms. Only two independent monomial invariants survive, reproducing Naumov and Toshev. The four-flavour extension gives eleven invariants and shows the electron-sterile spurion obstructs any monomial invariant — a sharp structural criterion for sterile searches.
An Axial $U_A(1)_{L_μ-L_τ}$: UV Completion and Experimental Searches
An anomaly-free, renormalizable axial $U_A(1)_{L_\mu-L_\tau}$ where opposite chiralities carry opposite charges, so muon and tau masses come from a universal seesaw with heavy vector-like leptons rather than ordinary Yukawas. The seesaw is doing flavour work, not just neutrino-mass work. Note the finite-$m_\mu$ trident calculation: $A'$ shifts the axial rather than the vector coefficient, which changes how trident data constrain the model.
Fixed points of the CKM matrix renormalization group running to all orders in perturbation theory
Dolan shows the six fixed points of the one-loop CKM RG running are fixed points to all orders in perturbation theory, removing an assumption on the running that the earlier proof needed. Relevant for anyone asking whether a flavour texture imposed at a high scale — GUT or modular — is RG-stable: an all-orders statement about the mixing-matrix flow is exactly the kind of input that constrains high-scale model building.
Drinfeld modular forms of higher rank from a lattice-oriented point of view
Drinfeld modular forms of rank $r$ built from a space of rank-$r$ lattices with level structure, with a metric, a completion, and a decomposition of that completion into lower-rank pieces. The higher-rank/several-moduli setting is the function-field mirror of what Siegel and Hermitian modular forms do in multi-modulus modular flavour symmetry — same organising principle, different arithmetic.
Exploring $Z/γ$-mediated heavy FCNCs at the FCC-ee
SMEFT dipole and Higgs-current operators mediating third-to-first-two-generation transitions via $Z/\gamma$, with optimal-observable sensitivities at FCC-ee energies and complementary low-energy constraints. Third-generation FCNCs are where most flavour-symmetry constructions make their least protected predictions, so the projected reach is a useful benchmark for how much a discrete or modular flavour model can still hide.
Astrophysical Sensitivity Projections for the IceCube Upgrade
Projected sensitivities for the IceCube Upgrade, now installed in the DeepCore infill with multi-PMT modules. The order-of-magnitude gain below $10$ GeV is the number that matters here: that is the energy range where atmospheric oscillations, $\nu_\tau$ appearance and sterile searches live, even though the paper frames the three benchmark analyses astrophysically (transients, NGC 1068, Galactic diffuse).
Characterizing Single-Signal Events from Atmospheric-Neutrino Neutral-Current Interactions in Large Liquid Scintillator Detectors
Systematic study of the model dependence of atmospheric-neutrino neutral-current singles in large liquid scintillators, i.e. the irreducible background to the JUNO-class MeV programme. The dominant uncertainty is the primary neutrino-nucleus interaction, especially NC on carbon; de-excitation drives selection but not spectral shape. Sets the size of the systematic that any DSNB or reactor high-energy tail analysis has to carry.
KOFFEE: Kaon Observables at Future Fermilab Experimental Extensions
A dedicated rare-kaon programme at Fermilab parasitic on the neutrino complex, targeting $K^+\to\pi^+\nu\bar\nu$ and $K_L\to\pi^0\nu\bar\nu$. Both golden modes measured well enough to close the unitarity triangle from kaons alone, with EFT reach to $\mathcal{O}(100)$ TeV. The infrastructure argument is worth reading: it competes for the same protons as the long-baseline programme.
Celestial probes of dark matter electromagnetic interactions
Neutrino flux from dark-matter annihilation in the Sun and the Earth, plus Jupiter and white-dwarf heating, for spin-1/2 DM captured through electromagnetic moments. The Earth turns out to be the leading probe of millicharged DM. Dirac versus Majorana is treated explicitly, and the moment structure differs between the two — the usual selection rule, here with a celestial-body handle.
A microwave SQUID multiplexing concept for macro-cryogenic calorimeter arrays
Microwave SQUID multiplexing transplanted from neutrino-mass microcalorimeters to massive BGO and TeO$_2$ cryogenic calorimeters. The bottleneck is not bandwidth but input-coil sensitivity, needing a factor $10$-$30$ improvement. If it works it removes the few-tens-of-channels ceiling on TES readout in rare-event searches, which is the scaling constraint on the next generation of bolometric $0\nu\beta\beta$.
A first-principles binary neutron star merger model of GW170817, GRB170817A, and AT2017gfo
End-to-end GRMHD with neutrino-radiation transport through nucleosynthesis to kilonova light curves, reproducing GW170817, GRB170817A and AT2017gfo from one simulation. The large-scale dynamo produces both the jet and $\approx 0.08 M_\odot$ of neutron-rich ejecta. Neutrino transport sets $Y_e$ and therefore the r-process yield, so this is where merger neutrino physics becomes observationally testable.
Accelerating Optical Photon Simulation in DUNE with Opticks
First GPU optical-photon simulation at the $10$ kt scale: Opticks on the DUNE FD horizontal-drift geometry, $313\times$ over single-threaded GEANT4 with validated agreement, integrated into LArSoft. Mundane infrastructure with a real consequence — high-statistics photon-detection studies become affordable, which feeds directly into DUNE low-energy reconstruction and supernova-burst sensitivity.
Testing Narrow-jet Gamma-Ray Bursts as Sources of Ultrahigh-Energy Cosmic Rays
Can a local population of narrow-jet long GRBs, motivated by GRB 221009A, supply the UHECR flux? Mixed-composition injection is propagated under three source-evolution models and confronted with spectrum and $X_{\max}$ data, with cosmogenic neutrino and cascade $\gamma$-ray fluxes computed as the multimessenger consistency check. The neutrino prediction is the discriminant against IceCube and future radio arrays.
Orbifold Degenerations of Hirzebruch Surfaces
Orbifold degenerations of Hirzebruch surfaces, every one a partial smoothing of a toric surface, classified through mutations of Fano polygons and T-singularities. Not string compactification, but the same combinatorial machinery — toric degeneration, orbifold singularity, mutation — that governs how flavour structure emerges from a compactification geometry.
Modular Functors with Singularities from Vertex Operator Algebras Beyond Rigidity and Finiteness
Conformal blocks from vertex operator algebras assembled into an open-closed modular functor with singularities, without assuming rigidity or finiteness, described explicitly on Dehn twists. The mapping-class-group representation is the object whose modular subgroup is what modular flavour symmetry gauges — worth a look at how far the construction survives once semisimplicity is dropped.

arXiv digest — 2026-08-28

Fri, 28 Aug 2026 07:00:00 +0000

Curated arXiv digest for 2026-08-28 — neutrino physics, flavour symmetries and astroparticle physics.

Strong CP and the PMNS Phase in Dirac Left-Right Symmetry
Direct hit on leptonic CP: generalized parity fixes the bare QCD angle, and imposing reality on the Dirac lepton Yukawas turns the PMNS Jarlskog invariant into a prediction as a function of the lightest neutrino mass and the parity-breaking parameter. A Dirac-neutrino left-right construction that ties strong CP to $\delta_{CP}$ measurable at DUNE/HK.
Energy-dependent slow collective flavor conversion of supernova neutrinos
Multi-energy, multi-angle slow flavor conversion with multiple spectral crossings, solved in a periodic box. The quasi-stationary state is strongly energy-, angle- and mass-ordering-dependent, yet a box-like prescription borrowed from fast conversions reproduces it. Relevant for how much SFC can be coarse-grained inside CCSN simulations and for the impact on $\nu_e$ heating.
An Axial $U_A(1)_{L_μ-L_τ}$: UV Completion and Experimental Searches
Anomaly-free axial $U_A(1)_{L_\mu-L_\tau}$ where the opposite chiral charges kill the ordinary Yukawas and $m_\mu, m_\tau$ come from a universal seesaw with heavy vector-like leptons. The axial coupling modifies the axial rather than the vector coefficient in neutrino trident production — a clean discriminant against the standard $L_\mu-L_\tau$ model.
From Thermal History to Multi-Messenger Signatures in $\mathbb{Z}_3$ Symmetric Dark Sector
$\mathbb{Z}_3$-symmetric dark sector with a right-handed neutrino, a dark fermion carrying the relic and a scalar driving a strong first-order EWPT. Semi-annihilation and dark-sector conversion open parameter space; the interest here is the $N_R$ embedding tying the seesaw sector to a LISA/DECIGO-visible gravitational-wave signal.
Notes on Gepner Construction
Gepner models recast purely as orbifolds, distinguishing chiral from left-right diagonal orbifolding and exploiting the extra freedom in Type 0 SCFT orbifolds, with Arf-theory bookkeeping at higher genus. Directly relevant to the orbifold-CFT machinery underlying flavor symmetries from heterotic compactifications, including the mirror-pair criterion.
FlaSR: A Mathematica Package for the Automatic Generation of $U$-spin Sum Rules
Mathematica package generating amplitude and amplitude-squared $SU(2)$ flavor sum rules to all orders in symmetry breaking, with emphasis on $U$-spin. Useful tooling for anyone deriving sum rules from a flavor group: the amplitude-level completeness result is exactly the kind of statement one wants for discrete and continuous flavor symmetries alike.
The k-Rank Taylor Family: Canonical Harmonic Lifts, Principal Parts, and Rademacher Series
Number-theory side of the modular flavor toolkit: canonical harmonic lifts of a weight-$3/2$ vector-valued harmonic Maass form, higher Serre derivatives and Rademacher expansions for the $k$-rank moment family. Serre derivatives and vector-valued modularity are the same machinery used to build modular forms of higher weight in flavor models.
Exploring $Z/γ$-mediated heavy FCNCs at the FCC-ee
SMEFT dipole and Higgs-current operators mediating $Z/\gamma$ third-to-first/second generation transitions at FCC-ee, with optimal-observable sensitivities and complementary low-energy constraints. Gives the collider reach on the same flavor-violating structures that discrete flavor symmetries are built to suppress.
Getting Warmer: IceCube Nears Freeze Out
The Galactic diffuse neutrino flux at IceCube turned into limits on DM annihilation into neutrinos, with a cosmic-ray-model-independent longitude-distribution method improving existing bounds by a few. The template-based analysis already probes the thermal-relic cross section for TeV masses — neutrino telescopes as a genuine DM detector.
ANRe-M1: a GPU-accelerated numerical relativity code with multi-energy M1 neutrino transport
GPU-ported numerical-relativity CCSN code with energy-dependent M1 neutrino transport in BSSN-Z4c, validated against the earlier CPU framework and demonstrated in 3D collapse. Infrastructure that determines whether flavor-conversion physics can realistically be folded back into full simulations.
Accelerating Optical Photon Simulation in DUNE with Opticks
GPU optical-photon transport with Opticks at the 10 kt DUNE far-detector scale, $313\times$ faster than single-threaded GEANT4 with validated Monte Carlo fidelity, and integrated into LArSoft. Photon-simulation cost is a real bottleneck for high-statistics DUNE oscillation and supernova-burst studies.
Testing Narrow-jet Gamma-Ray Bursts as Sources of Ultrahigh-Energy Cosmic Rays
Tests whether a local narrow-jet long-GRB population, motivated by GRB 221009A, can account for the UHECR spectrum and composition, and computes the associated cosmogenic neutrino and cascade fluxes. The multimessenger consistency check is what makes or breaks the scenario at IceCube/Auger.
Source models of ultrahigh-energy cosmic rays
Broad survey of UHECR source candidates and their acceleration, with high-energy neutrino observations already excluding high-luminosity GRBs and leaving low-luminosity GRBs, engine-driven SNe and radio galaxies in play. A compact map of where astrophysical neutrino constraints bite hardest.
Finding and using interpretable latents in a neutrino foundation model with sparse autoencoders
Sparse autoencoders applied to an IceCube foundation model recover a validated atlas of physical concepts, and causal tests show the direction head barely uses them. Retraining an uncertainty head on the same representation cuts median angular resolution from $20.2^\circ$ to $3.2^\circ$ at 20% efficiency — a large gain for point-source searches.
Contact Structure-induced Symplectic Nearly Half-Flat $SU(3)$ Structure in Finite-$N$ Thermal ${\cal M}$-Theory
Proves the transverse $SU(3)$ structure induced by contact 3-structures on the $G_2$ sevenfold of the M-theory thermal-QCD dual is symplectic nearly half-flat, with $W_2^-$ the only surviving torsion class. Relevant as $G$-structure technology for compactification geometry, with a KK-reduced radial magnetic field as output.
Quantum cellular automata and invertible phases of matter
Invertible quasi-local algebras where the $c=1/2$ chiral Majorana net and the $(E_8)_1$ conformal net give Brauer-nontrivial classes, plus a proposed $\Omega$-spectrum of invertible phases. The holomorphic-CFT and $E_8$ lattice structures here are the same objects that generate modular forms in flavor constructions, approached from an entirely different direction.
Dark Matters of Principle: Principles in the Dark Matter Paradigm
A philosophy-of-physics dissection of the dark-matter paradigm through four case studies — SUSY WIMPs, axions, sterile neutrinos and primordial black holes — asking which principles actually do the work. Worth a read for how it frames the sterile-neutrino programme as principled inquiry rather than parameter scanning.

arXiv digest — 2026-08-27

Thu, 27 Aug 2026 07:00:00 +0000

Curated arXiv digest for 2026-08-27 — neutrino physics, flavour symmetries and astroparticle physics.

Quantum-Kinetic Leptogenesis and Gravitational Waves from Seesaw-Assisted Domain-Wall Dynamics
Two-right-handed-neutrino type-I seesaw where the same heavy-neutrino mass splitting that drives resonant leptogenesis also generates the radiative bias annihilating a $\mathbb{Z}_2$ domain-wall network. Density-matrix kinetics with $r_q=\Delta M/\Gamma_{N_1}$ organizing the separated/resonant/coherent regimes. The GW spectrum becomes a consistency relation among seesaw parameters rather than a direct measurement — a useful caveat, honestly stated.
Strong CP and the PMNS Phase in Dirac Left-Right Symmetry
Left-right symmetry with generalized parity, Dirac neutrinos, and a reality condition on the lepton Yukawas that converts the PMNS Jarlskog invariant from a free input into a prediction fixed by the lightest neutrino mass and the parity-breaking parameter. It ties leptonic CP violation to $\bar\theta$ in the quark sector: a genuine correlation between strong CP and oscillation data, testable once the absolute mass scale is pinned.
Energy-independent neutrino dephasing from an ultralight axion-like background
Derivative coupling of active neutrinos to an ultralight ALP dark-matter background produces dephasing set by the field difference between production and detection, giving a characteristic-function damping factor ($J_0(A_{ij})$ for a single coherent mode) with $L^2E^0$ scaling — energy-independent, unlike standard decoherence. Recast of the first JUNO damping constraint onto the $g_2=g_3$ benchmark gives $|\Delta g_{21}|\lesssim0.90\,$GeV$^{-1}$.
Notes on Gepner Construction
Watari and Nishikawa reformulate the Gepner construction as a genuine orbifold, distinguishing chiral from left-right diagonal orbifolding and using the extra freedom of Type 0 SCFT orbifolds, with Arf-theory bookkeeping for higher-genus amplitudes. Relevant if you care about where flavor symmetries come from: Gepner points are the exactly solvable corner of heterotic compactification, and the discrete symmetries are read off the orbifold data.
A Rotational Perturbative Correction to Democratic Neutrino Mixing and JUNO Compatibility
Democratic mixing, killed by T2K/Double Chooz/Daya Bay, revived with unitarity-preserving rotational perturbations in the (1,2), (1,3), (2,3) sectors and confronted with NuFIT 6.1 and JUNO. The interest is the texture-by-texture allowed/disallowed map: JUNO's $\theta_{12}$ and $\Delta m^2_{21}$ precision is now sharp enough to discriminate among perturbed flavor-democracy ansaetze.
Resonant Induced Orbital Electron Capture: Novel method for low-energy $\bar{\nu}_e$ detection
Akhmedov, Lasserre and Maturi propose resonant induced orbital electron capture for $\bar\nu_e$ detection: the cross section depends on the flux spectral intensity at the resonance, not on the neutrino energy, so continuous sources satisfy the condition without fine-tuning. Candidate nuclides give access below the 1.8 MeV IBD threshold — reactor, geoneutrino and keV-scale thermal solar neutrinos, with an atomic-nuclear coincidence tag.
Development and Commissioning of the Cryogenic Target Detectors for the Technical Run of the NUCLEUS Experiment
NUCLEUS target-detector module for reactor-CE$\nu$NS at Chooz: four gram-scale CaWO$_4$ crystals with TES readout, mean baseline resolution $2.79\pm0.60$ eV and a best detector at $2.16$ eV, twice better than design, operated with the Ge outer veto without cross-talk. CE$\nu$NS at these thresholds is the cleanest lever on NSI and light mediators.
ADoNIS: A Differentiable generatOr of Neutrino Interaction Samples
ADoNIS is a fully differentiable neutrino interaction generator — exact derivatives propagated through the nuclear ground state, hard scattering and intranuclear cascade, following ACHILLES physics. The Jacobian shows directly which phase-space regions constrain which parameter and how probes break degeneracies. Cross-section systematics are the dominant limitation on DUNE/HK CP sensitivity, so this is infrastructure worth knowing.
NuGlass: A Fast and Interactive 3D Visualization of Neutrino Oscillations
NuGlass renders three-flavor evolution in six interactive 3D views — oscillogram surface, extruded bi-probability trajectory, Bloch-sphere flavor state, matter-eigenstate phasor decomposition, flavor-composition tube, and an $L/E$ worldline that makes matter-induced breaking of the vacuum degeneracy visible. Client-side, with experiment presets. Useful for teaching and for building intuition on degeneracies.
Finding and using interpretable latents in a neutrino foundation model with sparse autoencoders
Sparse autoencoders applied to an IceCube foundation model, with held-out tests, nuisance controls and replication across dictionary trainings. The direction head barely uses the learned concept atlas; an uncertainty head built on it improves median angular resolution from $20.2^\circ$ to $3.2^\circ$ at 20% selection efficiency. That is a large gain for point-source searches, obtained from interpretability rather than more training.
Remarks on Vafa-Witten theory, or how to sit on a wall
Refined $SU(N)$ Vafa-Witten invariants on Hirzebruch surfaces: the modular anomaly equation is simplified using generalized error functions extended to their singular loci, and indefinite theta series give the invariants at walls of marginal stability. The mock-modular machinery — completions, anomaly equations, indefinite theta series — is the same toolkit that governs modular forms of level $N$ in modular flavor symmetry.
Dark Matters of Principle: Principles in the Dark Matter Paradigm
Duerr and Read dissect the dark matter paradigm through the principles each approach is willing to break, with sterile neutrinos as one of four case studies alongside WIMPs, axions and PBHs. Worth the read as an outside view on how much 'minimal mutilation' of established physics a model-building programme can afford — a question the flavor-symmetry literature rarely asks about itself.

arXiv digest — 2026-08-26

Wed, 26 Aug 2026 07:00:00 +0000

Curated arXiv digest for 2026-08-26 — neutrino physics, flavour symmetries and astroparticle physics.

Discovery Potentials for the Cosmic Neutrino Background using Single Arm Interferometer
Single-arm interferometry with squeezed light as a probe of the cosmic neutrino background through a magnetic-moment coupling, reaching $10^{-25}\,\mu_B$ in the super-Heisenberg $N^2$ regime. That sensitivity is well below the Dirac SM value and sits where Majorana transition moments from TeV-scale seesaw completions live.
SU(9) grand unified model with rank-reducing discrete boundary conditions on $T^2/\mathbb Z_4$
Six-dimensional SU(9) on $T^2/\mathbb{Z}_4$ with rank-reducing discrete boundary conditions and Wilson-line phases: exactly the orbifold-GUT corner you care about. Quarks and leptons sit in separate bulk multiplets (36 and 84), which kills gauge-mediated proton decay outright and reshapes the flavour structure, while the two Higgs doublets emerge as Hosotani zero modes.
Note on arithmetic structure of modulus vacua in flux compactifications
Kobayashi and collaborators find Farey-sequence and void structure in the distribution of flux-stabilised moduli on $T^6/(\mathbb{Z}_2\times\mathbb{Z}_2')$, with vacua related by Gauss composition, including CP. This is the arithmetic backbone of modular flavour symmetry: the same $SL(2,\mathbb{Z})$ orbit structure that fixes modular weights also controls where CP breaks spontaneously.
CMB Birefringence from Axion String Networks Calibrated to an AMR Simulation
Anisotropic CMB birefringence from axion strings, calibrated on an AMR simulation, gives $|\mathcal{A}| < 0.24$ on the electromagnetic anomaly coefficient independently of $f_a$. That excludes the minimal GUT prediction for $\mathcal{A}$ at high significance — a rare cosmological constraint that bites directly on unified embeddings.
Mellin space reflections, modularity of elliptic Gamma functions and beyond
Modular transformation formulas recast as Mellin-space reflection identities, with the polynomial anomalies coming from contour deformation; extended to the elliptic Gamma function and the $SL(3,\mathbb{Z})$ trilinear relation. A different organising principle for building modular objects, potentially useful for constructing higher-level modular forms in flavour models.
Modular Forms Related to Real Quadratic Fields as Traces of Cycle Integrals
Locally harmonic Maass forms realised as traces of cycle integrals, showing that the representations of Zagier's $f_{k,D}$ and Mono's $g_{k+1,D}$ are not unique. Relevant if you work with weight-$k$ modular form bases: non-uniqueness of the cycle-integral representation means the same modular multiplet can be presented in inequivalent ways.
Exploring ESS$ν$SB Near Water Cherenkov Detector Designs Through Graph Neural Network Flavour Identification
GNN flavour identification for the ESS$\nu$SB near water Cherenkov detector, showing that a volume eight times smaller keeps $\nu_e/\nu_\mu$ CC separation nearly intact. Near-detector systematics are the limiting factor on the leptonic CP phase in the second-maximum strategy, so the design margin here translates directly into $\delta_{CP}$ reach.
Expected performance of a water Cherenkov detector for reactor antineutrino--electron scattering
Reactor $\bar\nu_e$-electron elastic scattering in a 170-ton water Cherenkov at the RENO near site, with the spectrum normalisation extracted from recoil directionality at the 1% level. A purely electroweak channel with no nuclear form-factor baggage, so it is a clean normalisation anchor and a handle on neutrino magnetic moment and NSI.
Unification of Gravity with Internal Interactions: the SO(2,16) Scheme Revisited
Full version of the SO(2,16) scheme trailed yesterday: conformal and fuzzy gravity unified with SO(10) internal interactions through a tangent group larger than spacetime. Here they work out the symmetry-breaking chain and fermion content in detail, plus cosmic-string GW signals — the concrete part that lets you judge the GUT embedding.
Direct lattice QCD calculation of the $θ$-induced CP-violating pion-nucleon coupling
First direct lattice determination of the $\theta$-induced CP-violating $\pi NN$ coupling, $\tilde g_{\pi NN}=0.0306(56)(124)\,\bar\theta$, consistent with the indirect estimate from the strong $n$-$p$ splitting. This is the matrix element that converts nEDM limits into bounds on CP phases, including those generated by flavour and GUT-scale physics.
Critical bifurcation and deconfined quantum criticality in an interacting cluster Ising chain
An exact $O(3)$ flavour symmetry among three Majorana chains, broken by interaction down to its cyclic subgroup $C_3$, splitting a triplet into singlet plus doublet with independently closing gaps. The $O(3)\to C_3$ pattern and the resulting $\mathbf{1}+\mathbf{2}$ decomposition is the exact group theory of $A_4$ flavour models, realised in a solvable spin chain.
Poincaré duality in Hida families
Poincare duality for $p$-adic Hida families, generalising the Atkin-Lehner involution to locally symmetric spaces and pairing anti-ordinary cohomology classes. Deep machinery on families of modular forms; if modular flavour symmetry ever needs a $p$-adic or arithmetic-family formulation, this is the kind of duality structure that would underlie it.

arXiv digest — 2026-08-25

Tue, 25 Aug 2026 07:00:00 +0000

Curated arXiv digest for 2026-08-25 — neutrino physics, flavour symmetries and astroparticle physics.

Neural Boltzmann Equations
Boltzmann solver replacing fixed momentum grids with physics-inspired neural distribution functions plus importance-sampled Monte Carlo phase-space integrals and natural-gradient evolution. Demonstrated on a precision $N_{\rm eff}$ computation. The relevant point is the parameter-scan capability: leptogenesis and sterile-neutrino thermalisation networks are exactly the regime where quadrature dies.
Generalized Chiral $U(1)_{B-L}$: Towards a Less Constrained $Z'$ and Dark Matter
Generalised chiral $B-L$ charges that keep anomaly cancellation but suppress $Z'\to\ell\ell$, evading LHC dilepton bounds. Neutrino masses come from a Dirac type-I seesaw, and the charge structure stabilises the scalar DM without an ad hoc discrete symmetry. Worth reading for the charge-assignment technique: the same two-parameter family constrains which Dirac-mass textures are gauge-allowed.
Search for the lepton-flavor-violating decay $ τ^{\pm} \to μ^{\pm} γ$ at Belle II
New Belle II bound $\mathcal{B}(\tau\to\mu\gamma)<9.5\times10^{-8}$ at 90% CL, from 428 fb$^{-1}$. Hard number to feed into any flavour model with $\mu$-$\tau$ structure: SUSY-GUT and modular-symmetry constructions generically predict cLFV correlated with the neutrino mixing angles, and this tightens the allowed slepton-mixing/seesaw-scale window.
Perturbative Anomaly Inflow on Orbifolds
Anomaly inflow computed directly on orbifold fixed loci via Donnelly's equivariant APS theorem, applied to A-type orbi-instantons at an M9 wall probing $\mathbb{C}^2/\mathbb{Z}_k$. The flavour symmetry appears as the centraliser of the embedding $\rho:\mathbb{Z}_k\to E_8$ — precisely the mechanism by which orbifold geometry fixes the flavour group in heterotic constructions.
Conformal and Noncommutative Gravity from Gauge Symmetry Breaking and SO(2,16) Unification
Gauge-theoretic gravity unified with an $SO(10)$ GUT inside $SO(2,16)$, exploiting the fact that the tangent-space group need not match the spacetime dimension. Non-standard route to embedding the fermion content, and the noncommutative/fuzzy version gives a UV completion where the internal and spacetime symmetries share one algebra. Review-style, useful as an entry point.
Toward a Unified Axion Cosmology
QCD axion from PQ symmetry inside SUSY $SO(10)$, extended to the ultralight ALP spectrum of heterotic compactifications. Two eigen-directions are singled out: $10^{-22}$ eV as fuzzy DM seeding early SMBHs, $10^{-28}$ eV as a transient pre-recombination component addressing $H_0$. The multi-axion/multi-instanton alignment machinery is the same used to engineer moduli stabilisation in orbifold models.
Two-loop renormalisation and Higgs phenomenology in the five-dimensional MSSM
Complete two-loop RGEs for the 5D MSSM, with the dangerous leading two-loop terms cancelling by virtue of the underlying $\mathcal{N}=2$ SUSY, and KK-resummed Higgs effective potential. Power-law running is what makes 5D unification qualitatively different from 4D; the paper bounds the compactification scale from Higgs couplings and EW precision.
Kohnen--Ueda local newforms
Local newform theory for the rank-1 metaplectic group, i.e. the representation-theoretic backbone of half-integral weight modular forms. Metaplectic flavour symmetry uses exactly these: half-integral weight forms furnish the doublet representations that ordinary $\Gamma_N$ modular flavour models cannot. Useful if you want the local/adelic structure behind the level-raising operations.
Three-Technology Ultra-High-Energy Neutrino Flavor Measurement
First concrete three-technology strategy to actually measure the UHE flavour ratios: in-ice radio, Earth-skimming and optical Cherenkov combined. Flavour composition above 100 PeV is the cleanest handle on production mechanism at the source and on propagation-induced new physics (neutrino decay, Lorentz violation, pseudo-Dirac splittings). Directly relevant if you care about what oscillation phenomenology looks like at cosmological baselines.
Cosmological extra dimensions can mimic dark matter I. Dark matter in galaxies
Compactified extra dimensions with a space-dependent radius $R$ sourced by visible matter density and the Newtonian potential, tuned to reproduce spiral-galaxy rotation curves. Speculative, but the mechanism — a dynamical compactification modulus responding to local matter — is the same class of object that fixes flavour structure in extra-dimensional models. Six proposed tests.
The ETH matrix model for DSSYK: non-perturbative corrections and intersection theory
The discrete volumes $N_{g,n}$ of the ETH matrix model for DSSYK sit in the ring of quasimodular forms generated by $E_2,E_4,E_6$, and $S$-duality on that ring produces the exact leading non-perturbative correction. Same algebraic object you use for modular flavour models — here it controls a genus expansion instead of Yukawa textures.
Ricci-flat string algebroids
4-forms determining string algebroids, canonical instantons, and generalised Ricci-flat metrics across almost-Hermitian, $G_2$ and $\mathrm{Spin}(7)$ structures. The unified torsionful framework is the geometric substrate of heterotic compactification — worth a skim for how much of the flavour-relevant structure is fixed by the 4-form alone.

arXiv digest — 2026-08-24

Mon, 24 Aug 2026 07:00:00 +0000

Curated arXiv digest for 2026-08-24 — neutrino physics, flavour symmetries and astroparticle physics.

A window for the mixed same-sign signature in the type-II seesaw models
Type-II seesaw phenomenology done properly: the triplet mass splitting is not free, electroweak loops pin it to 767-841 MeV once $\lambda_4$ vanishes at $\bar\mu = M_{H^{\pm\pm}}$. That single fact reopens $H^{\pm\pm}\to H^\pm W^{\pm(*)}$ at up to 40% of the width and shifts published exclusion boundaries by $-1.4\%$ and $+24.5\%$. Directly relevant if you read LHC triplet limits as constraints on the type-II mass mechanism.
Anomaly-free axion-like particle in Nelson-Barr models
Nelson-Barr with a $Z_N$ solves strong CP by spontaneous CP violation and, for free, delivers an anomaly-free ALP whose couplings to quarks are dictated by the CKM matrix rather than by anomalies. Photon and gluon couplings are suppressed, so the probe is rare meson decays plus SN1987A cooling. A clean case of discrete symmetry fixing flavour-violating structure.
Neutron star matter with hyperons: Bayesian comparison of nucleonic and SU(6)/SU(3) hyperonic models
Bayesian comparison of nucleonic, SU(6)-flavour-symmetric and free-parameter SU(3) hyperonic equations of state. The posteriors favour a vector coupling ratio $\alpha_v$ below the SU(6) quark-model value $\alpha_v = 1$, which stiffens the EoS enough to survive multimessenger bounds. Direct Urca thresholds move with it, so the neutrino cooling channel is part of the discriminant.
$G_2$-Manifolds from 4d $\mathcal{N}=1$ Quivers
$G_2$-holonomy sevenfolds built to geometrically engineer 4d $\mathcal{N}=1$ quivers obtained by flux torus compactification of 6d $(1,0)$ SCFTs, worked out explicitly for the rank-1 E-string. The construction is the compactification-geometry side of the field-theory/geometry dictionary that also governs where discrete flavour symmetries come from.
New Limits on $n \rightarrow n'$ Transformation from HFIR Cold Neutron Beam
Order-of-magnitude improvement on $n\to n'$ vacuum mixing for $\Delta m$ between 0.1 and 1000 neV, using a 6.6 T gradient at HFIR to drive the non-adiabatic transition. The two-parameter ($\Delta m$, $\theta_0$) formalism is the same active-sterile oscillation structure you use for neutrinos, transposed to a $\mathcal{B}$-violating baryon sector.
High-Energy Neutrino Constraints on memory burdened Bardeen and Kerr Primordial Black Holes
Memory-burdened PBHs below $10^{15}$ g survive to today, and their primary plus secondary neutrino emission is now confronted with IceCube, Super-K and ANTARES, plus IceCube-Gen2, GRAND200k and Hyper-K projections. Bardeen regularisation weakens the bounds; residual Kerr spin strengthens them substantially. A concrete case where neutrino telescopes set the leading dark-matter constraint.
Nucleosynthesis in the Accretion-induced Collapse of magnetised, Rotating White Dwarfs
Three-dimensional GR neutrino-MHD simulations of accretion-induced collapse post-processed with WinNet: the fastest-rotating magnetised model reaches the $A \approx 130$ r-process peak, while $^{56}$Ni stays five to forty times below core-collapse yields. A faint, neutrino-driven transient channel for neutron-star formation that is not a standard supernova.
Generation of TeV Photons by PeV Neutrinos in Dense Astrophysical Environments
Neutrino-nucleon scattering in the optically thin outskirts of dense environments converts PeV neutrinos into TeV photons with probability above 13%. Applied to the preburst TeV emission of GRB 221009A. Relevant if you care about multimessenger consistency between the IceCube/KM3NeT UHE events and the LHAASO-class photon sky.
CDRL: Certification-Driven Reinforcement Learning for Neutrino Flavor Model Discovery
An RL search over a $10^{26}$-model neutrino flavour hypothesis space, where symbolic certificates tell the agent why a candidate failed instead of just scoring it. Up to $6\times$ more valid neutrino models per candidate evaluated, and 40 interpretable rules extracted from the trajectories. Worth reading for the extracted rules alone: they are model-building heuristics stated explicitly.
Finite Weyl polynomials and the approach to Tsirelson's bound in relativistic scalar quantum field theory
Modular theory, not modular forms — but the machinery is the same complex-analytic control over a boost spectrum. Finite Weyl polynomials localised in complementary wedges approach Tsirelson's $2\sqrt{2}$ without ever attaining it; a degree-511 member reaches 2.80027. A pleasant reminder of how much structure sits in the modular flow of a free 1+1d scalar.
BMPV black holes in higher-derivative supergravity
Four-derivative corrections to the BMPV black hole in the 5d STU model, with the vector invariants shown not to correct the entropy and the heterotic piece matching recent results. The line worth noticing: the authors state the computation was made possible with AI assistance, in a hep-th paper, as a matter of method rather than novelty.

arXiv digest — 2026-08-21

Fri, 21 Aug 2026 07:00:00 +0000

Curated arXiv digest for 2026-08-21 — neutrino physics, flavour symmetries and astroparticle physics.

TeV-scale leptogenesis in a parity symmetric neutrino mass model
Leptogenesis in the minimal-Higgs $SU(2)_L\times SU(2)_R\times U(1)_X$ parity model, where neutrino masses are radiative and lepton number breaks through Yukawas. Decoupling $m_\nu$ from the CP asymmetry lifts the usual Davidson-Ibarra ceiling: non-thermal production pushes $v_R$ down to $\sim 10$ TeV, collider range. Strong CP is solved by parity alone, without an axion.
Cosmic Evolution of the Standard Model Flavor Charges
Complete flavour-covariant Boltzmann system for the 15 approximate $U(1)$ charges above the electroweak scale: five density matrices, all Yukawas, QCD and EW sphalerons. Reproduces standard leptogenesis results and extends to quark-sector asymmetries. The public code BOLEH makes this the new baseline for anyone quoting a flavoured efficiency factor.
Electroweak Baryogenesis in Top-Philic Type-III Two-Higgs-Doublet Model motivated by the $t\bar{t}$ Excess at the LHC
Top-philic Type-III 2HDM fitted to the CMS/ATLAS $t\bar t$ threshold excess, then asked to produce the baryon asymmetry via a strong first-order transition. Explicit vs transitional CP violation are compared; the explicit case stays scheme-dependent at one loop. Useful as the electroweak-baryogenesis counterpoint to leptogenesis, now anchored to a live anomaly.
The Radioactive Background of the JUNO Calibration System
Full radioactivity budget of the JUNO calibration hardware: HPGe assays, neutron activation analysis, Monte Carlo, and in-situ validation. Total contribution $<76$ mHz against a 200 mHz allowance. Dry, but this is the systematics floor underneath JUNO's mass-ordering determination.
Modularity theorems for Eisenstein congruences in prime-power level
Modularity theorems for Eisenstein localizations of the weight-2 $p$-adic Hecke algebra at levels $N$ and $N^2$, identified with quotients of a universal pseudodeformation ring. Weight-2 forms at level $N$ are the raw material of modular flavour symmetry; controlling the Eisenstein component and its congruences bears on which modular multiplets can appear at composite level. Note: the keyword pre-filter missed this one ('modularity', not 'modular form').
On the Finiteness of Isolated $j$-invariants for $X_1(N)$
Finiteness results for isolated $j$-invariants on $X_1(N)$ and sharpened torsion bounds for non-CM elliptic curves over $\mathbb{Q}$. The arithmetic of $\Gamma_1(N)$ level structure is the same object that fixes which finite modular groups $\Gamma_N'$ are available as flavour symmetries. The link is structural rather than immediate, but it is the right corner of number theory.
Minimal Quark-Lepton Complementarity from a Rigid Deformation of Tri-Bimaximal Mixing
A three-family ansatz $U_{\rm PMNS}=V_{\rm CKM}^\dagger U_{\rm TBM}R_{n}(-3\theta_C/4)$ with zero new continuous parameters: a rigid rotation of tri-bimaximal mixing about the axis $(2,1,2)/3$, angle fixed by the Cabibbo angle. It outputs $\theta_{12}=33.29^\circ$, $\theta_{13}=8.46^\circ$, $\theta_{23}=49.19^\circ$, $\delta_{CP}=180.79^\circ$ — upper-octant and near-CP-conserving, so DUNE/HK kill or confirm it. The simplicity scan over 49,622 candidates is the interesting methodological part.
Solar Constraints on Heavy Neutral Leptons with $ν_τ$ Mixing
Solar production of MeV heavy neutral leptons via $\nu_\tau p$ scattering, with decay $e^+e^-$ seen by SOHO. Constrains $|U_{\tau N}|^2$ below $10^{-2}$ near $5$ MeV — over an order of magnitude past terrestrial limits in the worst-covered mixing channel. The Sun as a tau-neutrino beam is the trick worth stealing.
Maximal Enhancements in Eight-Dimensional Non-Supersymmetric Heterotic Strings
Order-two orbifolds of heterotic strings on $T^2$, classified via Kac's theorem and Narain-lattice shifts: 1210 maximal enhancement points, 71 tachyon-free, 25 with no shifted-sector massless scalars. Direct relevance for the orbifold origin of flavour — the enumeration of consistent shift embeddings and surviving gauge algebras is exactly the model-building input, even though the paper's target is the de Sitter swampland.
Observation of an excess at the top quark pair production threshold in the single-lepton channel
CMS confirms the $t\bar t$ threshold excess in the single-lepton channel at $6.1\sigma$, $\sigma=5.1\pm0.9$ pb, consistent with a colour-singlet pseudoscalar toponium. First genuinely new hadronic bound state at the LHC — and, per 2608.19651 above, a possible portal to the baryon asymmetry.
The Search Budget of the BSM Resonance Program
Counts the ATLAS BSM resonance program's trials factor in effective resolution elements: 104 spectra give $N_{\rm trials}=7.9\times10^3$, so $5\sigma$ global costs $6.55\sigma$ local — and scanning 46 times harder costs only $0.56\sigma$ more. A sobering piece of bookkeeping for anyone who quotes global significances in a flavour-anomaly fit.

arXiv digest — 2026-08-20

Thu, 20 Aug 2026 07:00:00 +0000

Curated arXiv digest for 2026-08-20 — neutrino physics, flavour symmetries and astroparticle physics.

The Radioactive Background of the JUNO Calibration System
JUNO's calibration hardware sits close to the target, so its radioactivity feeds straight into the singles budget that limits the mass-ordering measurement. HPGe screening plus neutron activation analysis and Monte Carlo give $<76$ mHz against a $200$ mHz allowance, validated in situ. Worth knowing how much of JUNO's background ledger is already closed.
Maximal Enhancements in Eight-Dimensional Non-Supersymmetric Heterotic Strings
A full classification of rank-preserving non-supersymmetric heterotic strings in 8D as $T^2$ orbifolds of the supersymmetric theories: $1210$ maximal enhancement points from Kac's theorem plus consistent Narain-lattice shifts, $71$ tachyon-free. The $T^2$/Narain-shift technology is exactly the machinery behind eclectic and modular flavour groups, so the enumeration of consistent order-two inner actions is directly reusable.
Revisiting Quark-Lepton Complementarity in the Precision Neutrino Era
Straight at the core of the flavour-structure question: the quark-lepton complementarity correlation matrix is re-fitted against PDG 2026 CKM inputs and the NuFIT 6.1 likelihood. The narrow 2016 atmospheric-angle prediction is retrospectively penalised at $\Delta\chi^2\simeq18$-$20$, while the broad correlation survives, and $\sim72\%$ of the ensemble still sits closer to tribimaximal than to bimaximal. A clean lesson on which QLC statements are actually robust.
Constraining Cosmic-Ray Acceleration and Escape in Middle-Aged Supernova Remnants with GeV-TeV Gamma-Ray Observations
Time-dependent modelling of W51C, IC 443, W44 and W28 including cosmic rays that have escaped into the surrounding molecular clouds. Steep injection ($\alpha\sim4.2$-$4.3$), $E_{\max}\sim100$-$300$ TeV, sub-Galactic diffusion coefficients; crucially the escaped component substantially raises the predicted TeV neutrino flux, upgrading middle-aged SNRs as candidate point sources for IceCube/KM3NeT.
Probing Sub-GeV Dark Matter with the Migdal Effect at JUNO
JUNO's 20 kton of scintillator repurposed as a sub-GeV WIMP detector through the Migdal ionisation signal, with annual modulation used to pull the aggregate rate out of the PMT dark rate. World-leading spin-dependent reach in the sub-GeV window claimed. Relevant as a template for how the same neutrino target buys non-neutrino physics.
A Rotor-Dressed Semiton State in a Monopole--Fermion Model
Four-flavour massless QED with a monopole: the semiton is given an explicit Hilbert-space construction via a bosonised fermion-rotor model, with the unitary that shifts the rotor and dresses each flavour channel with a particle-hole cloud. This is the Callan-Rubakov sector, i.e. the same physics that drives monopole-catalysed baryon-number violation in GUTs, and the flavour-channel bookkeeping is where the anomaly inflow lives.
Type IIA on Spin(7) manifolds with fluxes
Type IIA compactified to two dimensions on $\mathrm{Spin}(7)$-holonomy spaces with fluxes, tadpoles cancelled by OF1-planes, worked out explicitly on a toroidal $\mathrm{Spin}(7)$ orbifold. All untwisted shape moduli enter the flux potential, yet quantisation plus the tadpole bound may obstruct untwisted-sector vacua, and the volume is bounded by $7\chi/192$. A sharp reminder of how tight the orbifold moduli-stabilisation problem gets once flux quantisation is imposed.
Hecke-type action on higher order Herglotz-Zagier function
Hecke operators are shown to act on the Lewis-Zagier three-term functional equation, making the first of those period functions a Hecke eigenform and generating multi-term functional equations for the derivative of the higher-order Herglotz-Zagier function. The period-function side of modularity is the same structure that fixes modular-form Yukawa couplings by weight and level.
Universal Ramanujan-type congruences for prime-detecting quasimodular forms
For every prime $p$ there is an arithmetic progression on which every prime-detecting quasimodular form has $p$-divisible coefficients. Quasimodular forms are the $E_2$-containing extension of the ring that modular flavour models live in, and universal congruences constrain what integrality statements can survive when $E_2$ is switched on.

arXiv digest — 2026-08-19

Wed, 19 Aug 2026 07:00:00 +0000

Curated arXiv digest for 2026-08-19 — neutrino physics, flavour symmetries and astroparticle physics.

Can $γγ$ collisions rival $e^-e^+$ in probing doubly charged Higgs bosons?
Type-II seesaw phenomenology at a photon collider: $\gamma\gamma\to H^{\pm\pm}H_1^{\mp}H_1^{\mp}$ cross sections exceed the $e^+e^-$ ones by an order of magnitude, giving $5\sigma$ reach in $4\ell+\slashed{E}_T$ at $\sqrt{s}=830$ and $1245$ GeV. The doubly charged scalar is the smoking gun of the triplet Yukawa that generates $m_\nu$, so its production channels matter for testing type-II directly.
Lepton flavor violating decays $l_j \rightarrow l_iγ$ in the $U(1)_X$VLFM
LFV rates for $l_j\to l_i\gamma$ in a $U(1)_X$ extension with vector-like fermions and right-handed neutrinos. The same RH neutrinos that seed the seesaw drive the charged-lepton flavour violation here, so the parameter regions reachable by MEG-II and Belle II directly constrain the neutrino-mass sector of the model.
An Exact Analytical Bridge from Complex Yukawa Couplings to Fermion Masses and CKM/PMNS Mixing
Claims that imposing $[\mathbf{M}_R^2,\mathbf{M}_I^2]=0$ on the Hermitian mass-squared matrix collapses 18 parameters to 5 per sector, giving closed-form eigenvalues and a diagonalising $U_f$ controlled by a 2D flavour-ratio vector, with $V=U_1^\dagger U_2$. Worth checking how much of the CKM/PMNS structure survives the exact four-fold moduli degeneracy the ansatz enforces.
Precise Measurement of $δ$ at LBNE Using Only The Neutrino Sector
A concrete way to pin down $\delta_{CP}$ at DUNE/LBNE without leaning on the antineutrino run: exploit the energy dependence of $P(\nu_\mu\to\nu_e)$ and break the residual degeneracies with Gaussian priors on the already well-measured mixing parameters. Directly relevant to how leptonic CP violation will actually be extracted, and to the beam-energy optimisation debate.
Infrared Lines from Sterile-Neutrino Transition Magnetic Moments at JWST
Reframes keV sterile-neutrino dark matter searches: the $N_1\to N_2\gamma$ transition magnetic moment sets the photon energy by the mass splitting $\Delta m$, not by $m_{DM}$, moving the line into the JWST infrared band. Projected limits $d_{NN\gamma}\lesssim 7\times10^{-14}$ GeV$^{-1}$ for $0.1$–$1$ eV splittings, plus a Majoron benchmark.
An axion constraint from the diffuse supernova neutrino background indicated by Super-Kamiokande
The Super-K $2.6\sigma$ DSNB indication is turned into an axion-proton bound $|g_{ap}|<1.3\times10^{-9}$ from long-term neutrino-radiation hydro simulations. Unlike SN 1987A this does not hinge on one supernova, so it is a genuinely more robust probe of protoneutron-star cooling — and of any feebly interacting state that competes with neutrino emission.
From Variability to SED Modeling: A Multiwavelength Study of the Neutrino Blazar TXS 0506+056
Six years of optical monitoring of TXS 0506+056 plus time-dependent lepto-hadronic SED modelling across the 2017 neutrino flare, post-flare and quiescence. The radio lag of 800–900 days locates the emission region, which is the key systematic in tying the IceCube-170922A event to a specific zone of the jet.
Revisiting neutrino event epochs for the blazar PKS 0735+178 with TESS
TESS optical light curves of PKS 0735+178 during the window in which four neutrino observatories reported events. Fast-decay/slow-rise asymmetry and a multi-modal flux distribution give a handle on whether the optical flare and the neutrino epochs share a physical origin — a second, independent test case for blazar neutrino production.
Reply to "Revisiting bounds on neutrino dark matter interaction at spikes"
Cline and Puel defend their IceCube AGN-based bounds on neutrino–dark matter scattering against arXiv:2607.08904, which contested the treatment of DM density spikes. Short, but the disputed point — how much spike enhancement one may assume — sets the strength of essentially every $\nu$-DM interaction limit in the literature.
Infinitely many primes with a fixed Frobenius field for an elliptic curve over $\mathbb{Q}$
Deuring theory, singular moduli and intersection theory on modular curves — exactly the toolkit that decides which CM points $\tau$ can stabilise the modulus in modular flavour models. A number-theoretic result on how often a prescribed Frobenius field occurs is a reminder that the arithmetic of CM points is richer than the handful of fixed points usually invoked.
Big categorification on towers of classical groups and wreath product groups
Wreath products are the structural backbone of the discrete flavour groups ($\Delta(27)$, $\Delta(6N^2)$, $\Sigma$ series) used to fix lepton mixing. A uniform categorification giving Kac–Moody 2-category actions and modular block descriptions for their representation categories is a very different way to organise the character theory these models rely on.

arXiv digest — 2026-08-18

Tue, 18 Aug 2026 07:00:00 +0000

Curated arXiv digest for 2026-08-18 — neutrino physics, flavour symmetries and astroparticle physics.

7-branes and $Γ_0(2)$ Duality in Type 0B String Theory
Charge operators built explicitly from modular forms of Gamma_0(2), with two independent 7-brane charges from the abelianization Z x Z_4. The axio-dilaton is frozen at tau = (1+i)/2 in a background of eight Z_4 7-branes. The mechanics - a congruence subgroup, modular forms as physical objects, a modulus stabilized at a distinguished point of the fundamental domain - is the same machinery modular flavor model building runs on.
Multipolar Neutrino Radiation in Binary Neutron Star Mergers: Angular Structure, Rotational Variability, and Implications for Electron Fraction
Full GR simulations with M1 transport, decomposing the neutrino energy flux into spherical harmonics: a strong quadrupole survives the post-merger transient, the dipole stays subdominant (no one-sided emission), and an m=1 modulation at 0.6-0.7 kHz tracks differential rotation. The latitude-dependent equilibrium Y_e that follows sets the r-process yield.
Degrees of Genus-Two Split-Jacobian Loci and Humbert-Form Reconstruction
Siegel modular forms of level one on the genus-two Humbert locus H_{n^2}, with the degree formula deg_w F_n = k(H_{n^2}) - 10 nu(n) proved for all n. Humbert surfaces are where a genus-two modulus degenerates to a pair of elliptic curves - the region multi-modulus Siegel modular flavor models have to navigate when they reduce to products of Gamma_N factors.
Gromov-Witten theory of abelian varieties in families and modular forms
Quasimodularity of Gromov-Witten generating series for the universal abelian variety, conjectured for SL(2,Z) at all h and proved in genus 2 after tautological projection, with genus-2 invariants given as a Shimura lift of a product of Eisenstein series. Siegel quasimodular forms of higher genus are the object multi-moduli modular flavor symmetry needs and the structure theory here is ahead of the physics use.
Probing T and CP Violation at DUNE and T2HK
Core leptonic CP physics: instead of comparing neutrino and antineutrino channels, the T-odd observable is extracted from the L-dependence of P(nu_mu -> nu_e) at fixed energy, using neutrino data only. Combining DUNE and T2HK reaches ~4 sigma on the L-odd component, with DUNE's second oscillation maximum doing the work. A genuinely different handle on delta_CP, largely free of the nu/nubar cross-section systematics.
Measurement of reconstructed final-state kinematics in charged-current interactions on water using the J-PARC $ν_μ$ beam and NINJA emulsion detector
First NINJA emulsion study of proton kinematics down to 200 MeV/c on a water target in the J-PARC beam, at the 0.7 GeV flux peak. Only 82 events, so statistics-limited, but the proton angular distribution already shows tension with the T2K interaction model - exactly the nuclear-model systematic that propagates into the T2K/HK delta_CP measurement.
Unfolding the low-energy reactor neutrino flux from CE$ν$NS data with a finite Dirac sum
The reactor antineutrino spectrum below the 1.8 MeV IBD threshold has never been measured, and it is the dominant systematic for any low-threshold CEvNS programme. Writing the differential rate as a finite sum of Dirac deltas gives a shape-independent unfolding with pointwise confidence bands - directly relevant to how tightly reactor CEvNS can bound NSI and light mediators.
Cosmogenic neutrinos from FRII galaxies as potential origin of the ultra-high-energy KM3-230213A event
A cosmogenic interpretation of KM3-230213A from FRII lobes, with the FRII contribution to the UHECR flux fixed self-consistently from the radio luminosity function rather than tuned. The predicted flux matches the KM3NeT inference while staying inside UHECR and gamma-ray limits, and the full GRAND array would see 50-135 events above 10^17 eV in a decade.
The linear dilaton in cosmology and particle physics
A review of the one-parameter family of 5D backgrounds interpolating between AdS (nu=0) and linear dilaton (nu=1), i.e. between Randall-Sundrum holography and Little String Theory. Every case gives a gapped continuum for bulk fields, and the brane-world cosmology branch yields a pressureless holographic fluid as freeze-in dark matter. Useful if you care about what extra-dimensional geometry does to the spectrum.
Superspecial Points on Shimura Curves
Quaternionic Shimura curves are the natural generalization of the modular curve X(1) that modular flavor symmetry currently lives on, and this paper counts their superspecial points in characteristic p via Eichler class numbers and the Selberg trace formula. If finite modular groups beyond Gamma_N are ever going to come from somewhere, this is the arithmetic they will come from.
Positive Tensor-Network Kähler Metrics on gCICY Threefolds
Tensor-network ansatz for positive Kahler metrics on generalized CICY threefolds - the numerical Calabi-Yau metric problem that stands between a compactification and its actual Yukawa couplings. Relevant to anyone who wants flavor structure from geometry rather than from an imposed symmetry.

arXiv digest — 2026-08-17

Mon, 17 Aug 2026 07:00:00 +0000

Curated arXiv digest for 2026-08-17 — neutrino physics, flavour symmetries and astroparticle physics.

Nonstandard Solution for Anomaly Cancellation as Seesaw Neutrino Origin in the SM
Anomaly cancellation with 15 chiral fermions in arbitrary hypercharges admits a second, nonstandard solution whose exotic neutral lepton singlets are automatically the heavy right-handed neutrinos. Two copies give a rank-two minimal seesaw with one massless active neutrino and sharp predictions, $m_{\beta\beta} = 1.2$-$4.1$ meV (NO) or $15.9$-$48.9$ meV (IO). Seesaw from anomaly structure rather than imposed by hand.
Dirac, Majorana, and Weyl Spinors in Arbitrary Dimension and Signature
Convention-explicit classification of Dirac, Weyl, Majorana, symplectic-Majorana and Majorana-Weyl fields across all thirty-two Bott/dimension-mod-8 sectors, treating the real Clifford algebra and its even part separately. Exactly the bookkeeping needed to track which reality condition survives orbifold compactification and how a higher-dimensional Majorana structure descends to a four-dimensional Majorana neutrino mass.
Vector-Like Fermions at FCC-ee: NLO Higgs-Strahlung Signatures and Constraints
One-loop vector-like fermion effects on Higgs-strahlung at FCC-ee, including the scenario where a vector-like singlet mixes directly with the third-generation neutrino. Electroweak-precision bounds on that mixing already kill any observable shift in $\sigma(ZH)$ — a useful null result for how much heavy-neutral-lepton mixing a Higgs factory can still probe.
Shimura curves of discriminant 14 and 15 and associated Heun Functions
Explicit generators for the ring of quaternionic modular forms on the Shimura curves of discriminant 14 and 15, tied to Heun functions of the $(2,2,2,q)$ quadrilateral groups and the Picard-Fuchs equation of the associated abelian surfaces. Quaternionic and non-congruence modular forms are the natural next arena for modular flavour symmetry beyond the $\Gamma_N$ paradigm; this supplies the concrete rings.
Hurwitz class number relations and mock modular forms
An infinite family of Hurwitz-type class number relations obtained by replacing $m^2$ with positive-definite binary quadratic forms, built through a genus-dependent level-lowering operator. The level-lowering technology is directly the kind of tool used to relate modular forms of different level $N$ — the parameter that fixes the finite modular flavour group $\Gamma_N$.
Blazar Boosted Dark Matter in IceCube
IceCube constraints on blazar-boosted sub-GeV dark matter, with the dark-matter-nucleon cross section built from elastic, resonant single-pion and deep-inelastic contributions. The treatment of the resonance-to-DIS transition is the same modelling problem that dominates neutrino-nucleus cross-section systematics in accelerator oscillation experiments.
Improving lepton flavour universality tests with $K_L$ decays
Global fit of rare kaon decays combining the latest $K^+ \to \pi^+ \nu\bar\nu$ measurement with lepton-flavour-universality observables in $K^+ \to \pi^+ \ell^+\ell^-$, plus NA62 and KOTO-II projections for $K_L \to \pi^0 \nu\bar\nu$. A second local minimum away from the SM survives. Constrains the same leptonic flavour structure that flavour-symmetry models must reproduce.
On Galois extensions of geometric fixed point spectra
Unifies the $GL_1(\mathbf{Z}/n)$ and $GL_2(\mathbf{Z}/n)$ Galois actions on topological modular forms with $\Gamma_1(n)$ and $\Gamma(n)$ level structures — the very finite modular groups that define modular flavour symmetry, arriving here from derived algebraic geometry rather than from string compactification.
Building a Quantum Black Hole Microstate: A Bulk Path Integral for a Heavy Virasoro Primary
Modular invariance alone fixes the growth of the density of heavy Virasoro primaries to the Cardy value $\gamma = 1$; anything else forces a defect saddle. A clean reminder of how much rigidity modular invariance imposes on a spectrum, which is the whole bet behind modular flavour models.