16 September 2026

The vanilla scotogenic model (VSM) featuring three right-handed neutrinos and an inert scalar doublet, offers a unified explanation of neutrino masses, dark matter (DM), and the baryon asymmetry of the Universe through leptogenesis. The typical mass scale of such a scenario lies in the vicinity of $\sim$ 10 TeV and above, whereas enhanced second-generation Yukawa couplings lower the leptogenesis scale to $\sim 1$ \TeV, allowing the model to be probed at the future muon colliders. Adhering to DM, neutrino mass, Leptogenesis, and flavour dependent constraints, the charged scalar is likely to be a long-lived particle (LLP). We analyse both the prompt and displaced vertex signatures of the model to find that, prompt mono-photon signals remain challenging, but LLP searches offer a promising avenue to probe such a framework, subject to the timing resolutions, and displaced-vertex reconstruction efficiency.

The absence of new physics beyond neutrino masses between the weak scale and the Planck scale is referred to as the great desert. It is often seen as a nightmare scenario for particle physics. Here we argue, by contrast, that the great desert assumption in fact has dramatic implications: it predicts that the Standard Model has a semi-classical AdS$_4$ vacuum with CFT$_3$ dual and, under reasonable assumptions, must be accompanied by at least one extra dimension significantly larger than Planck length. We also present one plausible candidate CFT$_3$ to be ``the" dual to the Standard Model.

We develop a new framework in which eclectic groups are realised as flavour symmetries without flavons. Focusing on the group $Ω(1)$, we show that it can be realised as a finite image of the integral Jacobi group, i.e. the semidirect product of $H({\mathbb Z})$ with $SL(2,{\mathbb Z})$, acting on two moduli $(τ,z)$. The Heisenberg subgroup $H({\mathbb Z})$ leaves the modulus $τ$ unchanged, and its finite image $Δ(27)$ plays the role of the traditional flavour symmetry. We provide the ingredients needed to construct supersymmetric Jacobi-invariant theories, both in globally supersymmetric theories and in supergravity. We develop a realistic model of fermion masses within this framework and formulate a consistent CP symmetry, which can be imposed at the Lagrangian level and broken spontaneously by the moduli. We discuss how the conventional eclectic-flavour description is recovered in an appropriate limit. We also extend this geometric interpretation to the $T^2/\mathbb Z_4$ and $T^2/\mathbb Z_2$ eclectic building blocks, and clarify why the $T^2/\mathbb Z_6$ case is structurally different.

We identify a topological constraint on extremal $\mathcal{N}=1$ AdS$_3$ spectra that is not implied by genus-one modular covariance of the three even spin structure partition functions. Assuming the expected topological modular forms divisibility of the Ramond Witten index, we show that for infinitely many odd $n$ at central charge $c=12n$, an extremal holomorphic $\mathcal{N}=1$ superconformal field theory requires an odd number of Neveu--Schwarz primaries at the BTZ threshold. Thus the strict ansatz with no threshold primaries is excluded for this infinite family.

A field theory action, able to incorporate stringy gauge symmetry enhancement-breaking effects, which occur at particular points of moduli space in a heterotic string toroidal compactification framework, was previously constructed from three-point interactions and duality symmetries. Via doubled periodic coordinates and a non-commutative product, it encodes the non-Abelian structure in a background-independent form. Moduli-space dependence becomes manifest upon performing a generalized mode expansion. Here we further elaborate on this construction. In particular, we propose field transformations for the retained sectors that make up the foundations of a potential symmetry of the action and that, when mode expanded at enhancement points in moduli space, contain the usual non-Abelian gauge transformations. We also examine the covariance of the corresponding scalar derivative structures. Although the proposal must be regarded as a truncated version of a full, presently unknown field-theory description, it already encodes representations of massless and massive states containing up to one oscillator excitation. Finally, we relate the construction to gauged DFT with an extended tangent space by associating generalized Kaluza-Klein modes considered here with additional generalized-frame directions. At enhancement, their brackets reproduce the enhanced gauge algebra; away from enhancement, the same algebraic structure is recovered by rotating the Cartan basis.

Liquid-argon TPC oscillation analyses increasingly split samples into proton-tagged (Np) and proton-less (0p) topologies at the ~35 MeV tracking threshold, but the standard GENIE Reweight library has no dial that transfers events across this boundary. We propose a single empirical nuisance parameter, $f_{\rm mig}$, that fills this gap as a per-event reweight on nominal GENIE output, implementable without event regeneration. It is presented as a methodological diagnostic: an effective topology-transfer surrogate absorbing an unspecified combination of near-threshold proton mismodelling effects (proton-side FSI, nucleon-momentum distribution, RES $Q^2$ shape, MEC kinematic shape), not a measurement of any single microscopic mechanism. As a reference scale, the position-dependent mean-field energy loss absent from GENIE's cascade is estimated from the $^{40}$Ar density profile to be a few percent, consistent with proton-transparency differences reported between cascade and transport generators on MicroBooNE data. The primary constraint is a direct scan on the MicroBooNE simultaneous CC 0p/Np differential cross-section release with no sector-weight regularisation: $\hat{f}_{\rm mig} = 0.093 \pm 0.024$, $3.8σ$ (Wilks) / $3.2σ$ (empirical). A supporting NC $Δ$ radiative sideband fit gives $\hat{f}_{\rm mig} = 0.050^{+0.029}_{-0.022}$, conditional on sector-weight priors; the two datasets share flux/detector systematics and are corroborating rather than independent. Introducing $f_{\rm mig}$ also relieves a compensatory CCRES sector-weight suppression in migration-blind fits. The extracted parameter is best understood as a flux-integrated effective nuisance direction for the MicroBooNE BNB configuration, suitable as a candidate GENIE dial for future LArTPC analyses pending detector-level validation.

We investigate the sensitivity of future muon colliders to the anomalous magnetic moment of the tau neutrino within a model-independent effective field theory framework. The analysis is performed through the subprocess $μ^{-}γ\rightarrow μ^{-}ν\barν$ where the initial-state photon is described using the Equivalent Photon Approximation. Signal and background events are generated with MadGraph5$\_$aMC$@$NLO, followed by parton showering and hadronization with PYTHIA8. Detector effects are simulated using DELPHES3, while the event reconstruction and analysis are carried out via the MadAnalysis5 framework. Optimized kinematic selection criteria are determined for center-of-mass energies of 3, 10 and 30 TeV muon colliders. The expected sensitivities are evaluated using the Asimov significance method. The best sensitivity is obtained for the 30 TeV muon collider option, where the anomalous magnetic moment of the tau neutrino can be probed down to $μ_{ττ}=5.21\times10^{-8}\,μ_B$ at the 5$σ$ significance level assuming a 1\% systematic uncertainty. Our sensitivity bounds improve the current direct experimental limit reported by the DONUT Collaboration up to one order of magnitude and demonstrate the strong potential of future muon colliders for probing neutrino electromagnetic interactions.

Supernovae are major drivers of cosmic chemical evolution. They synthesize heavy elements and disperse them into the interstellar medium via their explosion shocks. Light elements are converted into heavier ones during both presupernova evolution and the explosive event itself. Supernova explosions generate nucleosynthesis environments rich in neutrons, protons, and neutrinos under unique thermodynamic conditions, which can enable the production of heavy elements beyond iron. Modern numerical simulations are constructing increasingly realistic explosion models of various supernova channels, providing more accurate nucleosynthesis conditions and chemical yields. In tandem with advances in large-scale spectroscopic surveys delivering precise, high-resolution stellar abundance data, as well as isotopic ratios from presolar grains and meteorites, our understanding of the supernova role in cosmic nucleosynthesis is poised to advance significantly. We review recent progress in modeling various supernova channels, with particular emphasis on nucleosynthesis yields derived from state-of-the-art simulations. We examine the roles of Type Ia, core-collapse, electron-capture, and pair-instability supernovae in producing intermediate-mass, iron-peak, trans-iron, and very heavy elements, as well as their characteristic chemical imprints. We also outline major theoretical uncertainties that affect yield predictions. We intend this review to serve as a timely reference for theoretical model development and a practical guide for interpreting observational abundance data.

Recent IceCube observations point to the ultra-high energy neutrino flux exhibiting a very soft spectral nature beyond tens of TeV, which is unexpected from the standard cosmic-ray neutrino connection. As a potential explanation for this behaviour, we investigate neutrino self-interactions in an extra-dimensional $ {U(1)}_{L_μ-L_τ} $ gauge theory, where symmetry breaking leads to a tower of Kaluza-Klein gauge bosons in compactified four dimensions. These multiple gauge bosons may enhance the attenuation of astrophysical neutrinos as they propagate in the C$ν$B medium. Unlike single-mediator scenarios, for example, which arise from broken $ {U(1)}_{L_μ- L_τ} $ gauge symmetries in four dimensions, the presence of a Kaluza-Klein tower of mediators produces multiple closely spaced resonances whose interference gives rise to a rich energy-dependent behaviour of the scattering cross-section over a vast range of incident neutrino energies. Alongside $s$-channel resonances, off-resonant $t$- and $u$-channel contributions also become important. We explore the possibility that repeated resonant scattering between astrophysical neutrinos and those in the C$ν$B, mediated by these new multiple gauge bosons may increasingly attenuate the former at higher energies, thereby addressing the possibility of softening its spectral nature within the consideration of a single power law.

Astrophysical neutrinos are a clear identifier of photohadronic interactions in sources of Ultra-High-Energy Cosmic Rays (UHECRs). As the Pierre Auger Observatory has shown that UHECRs exhibit a composition heavier than protons at Earth, we expect that these heavy primaries undergo nuclear cascades due to photodisintegration in the dense source environments from which they originate. In this contribution, we will derive the neutrino spectra including those originating from nuclei undergoing photohadronic interactions. This will be explored in the context of modeling the emission region of a gamma-ray burst. Photohadronic interactions will be modeled using the new framework for Cosmic Ray Stochastic Interactions for Propagation (CRISP), which employs an analytic approach to compute the underlying probabilistic description of UHECR interactions.

We present an updated calculation of dimuon production in neutrino-nucleus collisions - an important constraint of the relatively poorly-known strange-quark distribution - at next-to-next-to-leading (NNLO) order. Compared to the approach usually used in the literature, where one computes inclusive charm production and multiplies the cross section by corrective factors, we instead compute the dimuon production cross section directly using semi-inclusive deep inelastic scattering (SIDIS) and a data-fitted decay function. While inclusive charm production has previously been computed to NNLO, we are using the recently-computed NNLO SIDIS coefficients to calculate the perturbative parts of the entire dimuon production process at NNLO. We find a notable reduction of scale uncertainties at larger momentum-fraction $x$, where the NNLO corrections tend to increase the cross section. At smaller $x$, we find a decrease in the cross section, a behaviour which can be linked to the suppression of the strange sea and which may eventually alleviate the tension observed between dimuon neutrino and LHC heavy-gauge boson data.

A nucleus is conventionally called stable when no decay has been observed. We replace this phenomenological definition with a criterion based on conservation laws alone. For this purpose, we formulate a general decay form (GDF) for finite charge-neutral nuclear systems that includes all possible final configurations allowed by known conservation laws. A nucleus is absolutely stable if no allowed configuration has lower mass. A global search over all nuclei with measured atomic masses yields 84 absolutely stable nuclei. Beyond the criterion of absolute stability, we introduce a dimensionless decay-accessibility entropy SGDF to quantify the relative accessibility of GDF-allowed decay channels. We rank all naturally occurring isotopes according to their maximum SGDF values and predict their dominant decay modes and corresponding partial half-lives. We further identify promising candidates for natural alpha and two-neutrino double-beta decays. The resulting framework also provides a nuclear-scale perspective on the far-future evolution of matter, in which nuclear decay drives matter toward combinations of these 84 absolutely stable nuclei before still slower forms of matter evolution. These findings extend the conventional phenomenological stable-radioactive classification to a conservation-law-based framework for nuclear stability and provide a quantitative roadmap for future rare-decay searches.