Fri·Apr 24, 2026Friday·April 24, 2026

1. 01*

   Impact of different neutrino decoherence formalisms at the future long-baseline Experiments

   Rudra Majhi🇮🇳 · Koushik Pal🇮🇳 · Monojit Ghosh🇭🇷 · Rukmani Mohanta🇮🇳

   In this paper, we have studied the impact of two different formalisms of quantum decoherence in determining the sensitivities of the two future long-baseline experiments DUNE and P2SO. In formalism-A, we will assume that the decoherence matrix is defined in a matter mass eigenstate basis which is the basis that diagonalizes the Hamiltonian for neutrinos in matter, with a constant matter density. In formalism-B, we will define the decoherence matrix in the vacuum mass eigenstate basis and then rotate it to matter mass basis via an unitary transformation. By using different values of the decoherence parameter $\Gamma$, we will show how these two formalisms differ at the probability level and then we will demonstrate how the sensitivities can differ at the ${\chi }^2$ level. Our results show that if the values of $\Gamma$ are small, then these two formalisms yield same probability in vacuum. However, if the values of $\Gamma$ is large or if there is strong matter effect, then these two formalisms yield very different results.

   hep-phPRD(2026)·0 citations
2. 02*

   Masked-Token Prediction for Anomaly Detection at the Large Hadron Collider

   Ambre Visive🇳🇱 · Roberto Ruiz de Austri🇪🇸 · Polina Moskvitina🇳🇱 · Clara Nellist🇳🇱 · Sascha Caron🇳🇱

   Anomaly detection in High Energy Physics requires identifying rare signals against overwhelming backgrounds, without prior knowledge of the signal. We present the first application of masked-token prediction, a technique from Large Language Models, to this problem. A lightweight encoder architecture trained solely on background events captures the structure of Standard Model (SM) physics; at inference, sequences deviating from this learned structure are flagged as anomalous. We evaluate the approach on searches for four-top-quark production and supersymmetric gluino pair production, both featuring top-rich final states with substantial missing transverse energy, covering SM and beyond the Standard Model (BSM) scenarios. Strong performance on the four-top signature, which closely resembles background, demonstrates the method's sensitivity to subtle deviations. We further show that the tokenization strategy significantly impacts performance: deep-learned tokenization via vector-quantized variational autoencoders (VQ-VAE) outperforms look-up table tokenization. Comparison with established anomaly detection baselines confirms robustness. These results highlight the potential of token-based collider data representations combined with transformer architectures for new-physics discovery. Once trained on SM background, the model transfers across different BSM searches, enabling scalable, model-independent anomaly detection at reduced computational cost.

   hep-phhep-ex0 citations
3. 03*

   Multimessenger probes of Axions from Compact Objects

   Alessandro Lella🇮🇹

   Astrophysics plays a pivotal role in the quest for axions and axion-like particles, offering guidance to experimental efforts and enabling the investigation of axion properties that cannot be probed otherwise. In this context, the extreme conditions in the interiors of compact stellar objects -- such as core-collapse supernovae, neutron stars, and binary neutron star mergers -- significantly enhance axion production, providing unparalleled sensitivity to extremely feeble couplings to Standard Model particles. In this context, the techniques of multimessenger astrophysics deepens the understanding of powerful transient events, maximizing the capabilities of current instruments to identify possible signatures of axion emission.

   hep-phastro-ph.HE0 citations
4. 04*

   Jet Quenching Identification via Supervised Learning in Simulated Heavy-Ion Collisions

   Leonardo Lima da Silva🇧🇷 · Marcelo Gameiro Munhoz🇧🇷

   Jet modification in heavy-ion collisions provides microscopic access to the properties of the quark-gluon plasma. However, conventional approaches based on traditional global observables, such as \(R_{AA}\), capture limited information about the complex dynamics of parton-medium interactions during hard scatterings. In this work, we apply sequential machine learning architectures to the jet declustering history tree, achieving improved classification performance compared with static models that learn only from a single stage of the jet evolution. We find that models trained on different medium implementations exhibit meaningful performance modification under cross-domain validation, indicating that machine learning is sensitive to implementation-specific features that traditional observables may not resolve. These results suggest new opportunities for using machine learning as an analysis tool to overcome some of the limitations of traditional jet-modification studies.

   hep-phPRC(2026)·0 citations
5. 05*

   Ultra High Energy Cosmic Rays from the Local Void

   Michael J. Padgett🇺🇸 · Thomas W. Kephart🇺🇸

   Ultra high energy cosmic rays have been see coming from the direction of the local cosmic void. We use this fact to argue that at least some of these these cosmic rays are relatively light magnetic monopoles and that their relative fraction above 1020 eV can be found from full sky observations.

   hep-phastro-ph.HEhep-th0 citations
6. 06*

   Neutron Portal and Dark Matter-Baryon Coincidence: from UV Completion to Phenomenology

   Sudhakantha Girmohanta🇨🇳 · Yuichiro Nakai🇨🇳 · Yoshihiro Shigekami🇨🇳 · Zhihao Zhang🇨🇳

   We present a dynamical solution to the dark matter-baryon coincidence problem based on the neutron portal operator connecting the visible and dark sector asymmetries. This framework is motivated by the possibility that a strongly supercooled dark confinement phase transition accounts for the nano-Hz stochastic gravitational wave signal observed by pulsar timing arrays, while also generating the dark matter and baryon asymmetry in the Universe. We show that the GeV-scale mass of asymmetric dark matter can be naturally correlated with the (multi-)TeV scale cut-off for the neutron portal through its ultraviolet completion. The dark sector is governed by an approximate fixed point and confines once the heavy portal states are integrated out, dynamically generating a scale of $\mathcal{O}(\mathrm{GeV})$. We analyze both tree and loop-level ultraviolet completions and demonstrate how the resulting confinement scale is linked to the effective neutron portal scale. We also discuss cosmological constraints and experimental prospects in beam dump searches and colliders for probing the neutron portal.

   hep-phastro-ph.COhep-exJHEP(2026)·2 citations
7. 07*

   Disentangling new physics with quantum entanglement in $t\bar{t}$ production at future lepton colliders

   Masato Arai🇯🇵 · Kentarou Mawatari🇯🇵 · Nobuchika Okada🇺🇸

   We investigate quantum entanglement and Bell-inequality violation in top-antitop pair production at future lepton colliders such as the International Linear Collider (ILC) and multi-TeV muon colliders. Within the Standard Model (SM), the process proceeds through $s$-channel $\gamma$ and $Z$ exchange and exhibits characteristic spin-correlation patterns that encode a non-trivial amount of entanglement. We then examine how these features are modified in several well-motivated extensions of the SM:(i) a neutral scalar mediator that couples to charged leptons and top quarks via Yukawa interactions and contributes as an additional $s$-channel exchange; (ii) the minimal gauged $U(1{)}_{B-L}$ model, which introduces a new neutral gauge boson $Z^{\prime }$ coupling vectorially to SM fermions; and (iii) a Randall-Sundrum scenario, in which the exchange of massive Kaluza-Klein gravitons arising from a warped extra dimension induces additional spin-dependent interactions. For all cases, we evaluate quantum-information observables, including the entanglement marker, the concurrence, and the maximal Clauser-Horne-Shimony-Holt parameter, and study their dependence on the center-of-mass energy, scattering angle, and model parameters. We find that, relative to the SM expectation, the entanglement is typically reduced in the scalar-mediator scenario, while sizable deviations can arise in the $U(1{)}_{B-L}$ and Randall-Sundrum cases for phenomenologically relevant regions of parameter space. These results demonstrate the potential of quantum-information observables as sensitive probes of new particles and their interaction patterns in future lepton colliders.

   hep-phhep-thPRD(2026)·8 citations
8. 08*

   Comparing relativistic and non-relativistic quark pair creation models

   Xiu-Li Gao🇨🇳 · Yu-Hui Zhou🇨🇳 · Bin Wu🇨🇳 · Zhi-Yong Zhou🇨🇳

   We investigate the strong decay properties of light unflavored and strange mesons within a relativistic quark-pair-creation (QPC) framework, and compare the results with those obtained in the conventional non-relativistic QPC model. Our analysis shows that, within the present theoretical and experimental uncertainties, the relativistic QPC model yields predictions for strong decay widths of comparable overall quality to those of the non-relativistic QPC model. This indicates that the non-relativistic QPC approach remains adequate for estimating decay widths in most practical applications. Nevertheless, owing to the inclusion of Lorentz boosts and Wigner rotations, the relativistic QPC model exhibits a stronger suppression of decay amplitudes in the high-energy region. This feature may be useful in studies based on unquenched quark models, where the relativistic QPC coupling could lead to more controlled meson-loop effects and mass shifts.

   hep-ph0 citations
9. 09*

   Solving Cosmological Puzzles using Finite Temperature $\nu$SMEFT

   Debajyoti Choudhury🇮🇳 · Jaydeb Das🇮🇳 · Tripurari Srivastava🇮🇳

   We study a minimal framework that naturally yields viable Dark Matter, a strong first-order electroweak phase transition and low-scale resonant leptogenesis. Augmenting the Standard Model with three heavy Majorana neutrinos, we study the corresponding neutrino-extended Standard Model Effective Field Theory, including operators upto mass-dimension six. The pure Higgs operator provides the dominant enhancement required for a strong first-order electroweak phase transition, while the remaining operators yield subleading effects consistent with electroweak precision constraints. The signal for the stochastic gravitational-wave background is dominated by sound waves in the plasma, with magnetohydrodynamic turbulence providing a subleading contribution. Low-scale resonant leptogenesis is realized through tiny mass splittings among quasi-degenerate heavy neutrinos, dynamically generated in the symmetric phase by the combined effect of one-loop RG-induced corrections and finite-temperature contributions. Solving the Boltzmann equations, we show that the observed baryon asymmetry of the Universe can be reproduced while remaining consistent with neutrino oscillation data and charged-lepton-flavor-violation constraints. One of the heavy neutrinos is stabilized by a discrete symmetry thereby acting as a fermionic dark matter candidate. Its interactions with the Standard Model arise from dimension-five and dimension-six effective operators, leading to viable annihilation, elastic scattering, and indirect detection phenomenology compatible with current experimental bounds. The dark matter sector remains decoupled from the dynamics of the electroweak phase transition and leptogenesis, allowing all three phenomena to be consistently realized within a unified effective field theory framework.

   hep-ph2 citations
10. 10*

    $\gamma Z$-exchange contribution in elastic $ep$ scattering by perturbative QCD

    Qian-Qian Guo🇨🇳 · Hui-Yun Cao🇨🇳 · Hai-Qing Zhou🇨🇳

    In this study, we calculate the $\gamma Z$-exchange contribution to elastic $ep$ scattering at large momentum transfer within perturbative QCD. We present analytical expressions for the $\gamma Z$-exchange contributions to the amplitudes. We also estimate the asymptotic behaviors of the amplitude contributions and of the physical quantity $A_{\text{PV}}$ at high momentum transfer. These asymptotic behaviors determine the subtraction order in the dispersion relations (DRs) satisfied by the amplitudes. We find that the DR usually used in the literature for the axial-vector part of the amplitude is not valid at high $Q^2$ and should be modified to a once-subtracted form. Within the present pQCD framework and the adopted proton distribution amplitudes, these high-energy properties also provide nontrivial constraints on low-energy DR assumptions.

    hep-phPRC(2026)·0 citations
11. 11*

    Dilepton Production as a Probe of Pion Condensation in Hot and Dense QCD Matter

    Aritra Bandyopadhyay🇷🇴 · Chowdhury Aminul Islam🇩🇪 · Krzysztof Redlich🇵🇱 · Chihiro Sasaki🇵🇱

    We investigate dilepton production from an isospin-asymmetric hot and dense medium in order to explore the role of isospin imbalance in electromagnetic spectral properties. We focus in particular on modifications of the dilepton production rate associated with the onset of pion condensation, which can occur in the presence of a finite isospin chemical potential. We employ the Nambu--Jona-Lasinio model with isoscalar--vector interaction. We examine the phase structure in the $T-{\mu }_I$ plane and estimate the vector current correlator--resummed dilepton rate for an effective quark chemical potential. We find that the interplay between isospin asymmetry, pion condensation, and vector interactions leads to nontrivial modifications of the dilepton yield. In particular, we observe two key features of the pion condensed phase: an enhancement at lower invariant mass and a prominent plateau-like structure which also help clearly identify the pion condensed phase from a chirally broken/restored phase. These results highlight the potential sensitivity of dilepton observables to pion-condensed phase of QCD matter, with possible implications for future low-energy heavy-ion collision experiments as well as isospin-rich environments such as neutron star matter.

    hep-phnucl-thPRD(2026)·0 citations
12. 12*

    Constraining dark matter self-interaction from kinetic heating in neutron stars

    Sambo Sarkar🇮🇳

    Dark matter search strategies have started advancing towards the neutrino fog. In this regard, compact objects such as neutron stars have already demonstrated their ability in probing such low DM-nucleon cross-sections from dark matter induced effects. In the optically thin limit, effect of dark matter self-interaction becomes relevant and may assist the capture and thermalization of dark matter inside stars, imparting observable changes on neutron star temperatures. The resulting radiation although weak can be potentially detected by the James Webb Space Telescope and upcoming Thirty Meter Telescope and the European Extremely Large Telescope. Observation of cold neutron stars accompanied by advancements in direct detection probes would provide stringent constraints or a smoking-gun signature for dark matter self-interactions. The potential detection of a neutron star with surface temperatures $\sim (1000-1200)$ K in the optically thin limit can push the bounds on asymmetric dark matter self-interaction cross-section to approximately two orders of magnitude more stringent than the bullet cluster.

    hep-phastro-ph.GAPRD(2026)·1 citation
13. 13*

    True Leptonium ($l^{+}{l}^{-}$) Production in UPC Triphoton Interaction

    Qi-Ming Feng🇨🇳 · Qi-Wei Hu🇨🇳 · Cong-Feng Qiao🇨🇳

    True leptonium states ($l^{+}{l}^{-}$) are compact pure QED systems, first theoretically predicted eight decades ago. Although considerable efforts have been devoted to their search, only positronium has been experimentally confirmed shortly after its theoretical prediction. By contrast, dimuonium (${\mu }^{+}{\mu }^{-}$) and tauonium (${\tau }^{+}{\tau }^{-}$) remain unobserved to date, partly due to their low production yields. In this work, we find that a significant number of ortho-leptonium states can be generated through the triphoton interaction process in ultraperipheral heavy-ion collisions (UPCs). In this process, two photons are emitted from one beam, while the third photon originates from the other beam. This unique interaction mechanism thus provides a distinctive opportunity to pinpoint dimuonium and tauonium. Moreover, within the three-body interaction mechanism, we find that the experimental data for $J/\psi$ production and dimuon production in ultraperipheral Pb+Pb collisions at the Large Hadron Collider (LHC) can be well reproduced.

    hep-ph2 citations
14. 14*

    Odd Physics Off the Diagonal: Constraining CP-violating SMEFT with Quantum Tomography

    Avalon Roberts🇬🇧 · Patrick Dougan🇺🇸 · Alexander Oh🇬🇧 · Savanna Shaw🇬🇧

    New sources of charge-parity (CP) violation beyond those described in the Standard Model (SM) are required to explain the observed matter--antimatter asymmetry of the Universe. The Standard Model Effective Field Theory (SMEFT) provides a framework to introduce additional electroweak sources of CP-odd physics in a model-independent manner. However, these CP-violating signatures are mostly degenerate to CP-even SMEFT operators in polarisation-blind observables, distinguishable only in the SM-New Physics (NP) interference using the azimuthal decay angle. Using Quantum Tomography techniques, we present a new approach to constraining these NP effects. Reconstructing the spin density matrix (SDM) of a diboson system, we go beyond `interference resurrection' to exploit the full signature of the Beyond-SM physics, including the pure quadratic NP terms. We show that this approach provides superior simultaneous sensitivity to characteristic features of CP-even and CP-odd contributions, including effects not fully captured by traditional angular observables.

    hep-phhep-exquant-ph2 citations
15. 15*

    Analytical and Machine Learning Methods for Model Discernment at CE$\nu$NS Experiments

    Iain A. Bisset🇺🇸 · Bhaskar Dutta🇺🇸 · Doojin Kim🇺🇸 · Samiran Sinha🇺🇸 · Joel W. Walker🇺🇸

    Neutrino experiments are often limited by low statistics, sizable systematic uncertainties, and coarse observable binning, which can hinder discrimination among competing beyond-the-Standard-Model (BSM) explanations of anomalous signals. In particular, analyses based primarily on total event-rate differences are vulnerable to source-normalization uncertainties and to degeneracies among models that induce similar inclusive yields. Using stopped-pion coherent elastic neutrino-nucleus scattering (CE$\nu$NS) as a benchmark environment, we study how much model-discrimination power can be obtained from correlations in baseline, recoil energy, and timing that are less sensitive to the total rate. As benchmark BSM scenarios, we consider a $3+1$ sterile-neutrino framework and neutral-current non-standard neutrino interactions (NSI). We show with a likelihood-based analysis that these scenarios can be distinguished in nontrivial regions of parameter space once multidimensional shape information is retained. We further demonstrate with convolutional neural networks that substantial discrimination remains possible even after the total event rate is explicitly removed from the input, indicating that the relevant information is genuinely encoded in the shape of the CE$\nu$NS distribution. Finally, through multi-class classification within the sterile parameter space, we show that in favorable regions the same observables can support approximate localization of the underlying sterile-neutrino benchmark point. Our results highlight the complementary roles of conventional and machine-learning-based inference in moving neutrino new-physics searches from anomaly detection to physics interpretation.

    hep-ph0 citations
16. 16*

    Quark and gluon production in the presence of the time-varying chiral magnetic current

    Kirill Tuchin🇺🇸

    The chiral magnetic effect consists in the induction of the electric current along the direction of the magnetic field. The corresponding transport coefficient $b_0$, known as the chiral magnetic conductivity, is proportional to the chiral imbalance in the medium. In many systems, such as quark-gluon plasma, $b_0$ is time-dependent. This paper studies the effect of the time variation of $b_0$ on the particle spectra and energy loss produced through the chiral Cherenkov and associated processes in Abelian and non-Abelian systems. The rates of all processes are derived in the ultra-relativistic approximation. The results are applied to the relativistic heavy-ion collisions utilizing a specific model describing the relaxation of the initial $P$-odd domain within the quark-gluon plasma. The corresponding energy loss is computed. The results suggest strong polarization of jets in quark-gluon plasma.

    hep-phnucl-thPRD(2026)·1 citation
17. 17*

    Heavy Quark Transport is Non-Gaussian Beyond Leading Log

    Jean F. Du Plessis🇺🇸 · Bruno Scheihing-Hitschfeld🇺🇸

    We find that heavy quark transport beyond leading logarithm at weak coupling is intrinsically non-Gaussian: the longitudinal momentum transfer distribution has asymmetric exponential tails that are crucial for equilibration dynamics. We show this by computing the leading-order momentum transfer kernel for relativistic heavy quarks in weakly coupled non-Abelian plasmas, matching perturbative momentum transfer on the thermal scale to hard-thermal-loop-resummed soft physics. This is the same structure previously found in strongly coupled holographic plasmas, showing that it is not peculiar to weak or strong coupling, conformality, or supersymmetry. We therefore expect that this is a robust feature that physical quark-gluon plasma should also exhibit.

    hep-phhep-thnucl-th2 citations
18. 18*

    Determination of the sensitivity of the DEAP-3600 experiment to supermassive charged gravitinos

    Michał Olszewski (for the DEAP Collaboration)🇵🇱

    The lack of discovery of particle dark matter candidates within the favored mass-window range brings in the motivation for the study of new options brought by Planck-mass dark matter models. Extended supergravity theories predict the existence of non-relativistic gravitinos that could at least in part contribute to the missing mass-energy density of the Universe. The feasibility study for the discovery with DEAP-3600 experiment of Planck mass charged gravitino dark matter is presented. Additionally the expected signal events topology within the detector is discussed.

    hep-phastro-ph.CO0 citations
19. 19*

    Gradient-Produced Neutrinos

    Erwin H. Tanin🇺🇸 · Yikun Wang🇺🇸

    Sufficiently strong electric fields can produce charged-particle pairs via the Schwinger effect. We argue that steep matter-density gradients, as can arise in neutron star interiors, would analogously produce neutrino-antineutrino pairs. We then discuss observational signatures of these gradient-produced (anti)neutrinos and how they could provide new probes of neutron-star structure and baryon-dense QCD.

    hep-phastro-ph.HEastro-ph.SRnucl-th1 citation
20. 20*

    Dive deeper with SUBMARINE: SUB-Mev dArk matter diRect detectIon using bilayer grapheNE

    Rinchen Sherpa🇮🇳 · Anuvab Sarkar · Tarak Nath Maity🇦🇺 · Paramita Dutta · Ranjan Laha🇮🇳 · Anirban Das🇮🇳

    Novel target materials with anisotropic response will play a key role in detecting low-mass dark matter in upcoming experiments. Bilayer graphene is one such material that has been proposed for the detection of sub-MeV mass dark matter particles via electronic excitations. In this work, we calculate scattering rate via a massive mediator in bilayer graphene. With an exposure as small as $\sim$ 0.5 mg-year, bilayer graphene can probe new regions of the parameter space. The anisotropic response function of bilayer graphene leads to a sidereal-day modulation in the scattering rate, depending on its orientation with respect to the Galactic dark matter wind. We find significant modulation in the scattering rate for sub-MeV mass dark matter, demonstrating bilayer graphene's promise for a future experiment. We hope that our work will motivate the community to investigate bilayer graphene as a novel target material, and that it may lead us to discover the particle nature of dark matter.

    hep-phcond-mat.mes-hallhep-ex3 citations
21. 21*

    Flux Mixing and CP Violation in QCD

    Motoo Suzuki🇮🇹

    We argue that kinetic mixing between topological flux sectors generates an effective shift of the QCD $\bar{\theta }$ angle, thereby inducing CP-violating effects. To demonstrate this mechanism, we analyze a $(1+1)$-dimensional $U(1)\times U(1)$ gauge theory as a controlled setting, where kinetic mixing leads to observable shifts in electric fluxes. We then extend the analysis to four dimensions using a three-form field description of QCD coupled to an additional $U(1)$ three-form gauge field. We find that hidden-sector fluxes, through kinetic mixing, shift the effective $\theta$ parameter of QCD and induce a nonzero expectation value of $⟨G\tilde{G}⟩$. We discuss the implications for the strong CP problem and clarify under which conditions standard solutions, such as axion or CP/parity-based mechanisms, are compromised or remain robust.

    hep-phgr-qchep-th0 citations
22. 22*

    Hydrodynamics and Energy Correlators

    João Barata🇨🇭 · Matvey V. Kuzmin🇬🇧 · Ian Moult🇺🇸 · Andrey V. Sadofyev🇵🇹 · João M. Silva🇵🇹

    We study energy-energy correlators (EECs) in many-body quantum states, focusing on the matter produced in the aftermath of heavy-ion collisions. We analyze the angular structure of EECs in the collinear limit and identify a sequence of dynamical regimes. At the largest angular separations within the small-angle regime, the observable is dominated by disconnected contributions, leading to a classical scaling determined by the collective flow of the medium. We explicitly construct this contribution for hadrons produced from a hydrodynamic medium described by boost-invariant Gubser flow, obtaining the angular dependence of the EEC analytically. We further consider azimuthal perturbations to this flow, illustrating how EECs can be used to probe anisotropies in the initial state. At smaller angular separations, connected contributions become increasingly important. We argue that in this regime the EEC is controlled by collective hydrodynamic modes. The resulting angular behavior is similar to the one identified in the EECs of heavy and large-charge states of conformal field theories. At even smaller angles, this regime is expected to match onto the structure determined by the light-ray operator product expansion, before eventually crossing over to the smallest-angle behavior characteristic of dilute hadronic matter. Altogether, these results provide a unified picture of the angular structure of EECs in many-body QCD states and suggest new observables sensitive to the properties of matter in heavy-ion collisions.

    hep-phhep-exnucl-th5 citations
23. 23*

    Matchotter: An Automated Tool for Dimensional Reduction at Finite Temperature

    Javier Fuentes-Martín🇪🇸 · Javier López Miras🇪🇸 · Adrián Moreno-Sánchez🇪🇸

    At finite temperature, the decoupling of heavy Matsubara modes allows a four-dimensional quantum field theory to be matched onto a purely spatial, three-dimensional effective field theory (EFT). This dimensional reduction is a crucial prerequisite for the precise computation of thermal observables, most prominently those related to cosmological phase transitions. In this work, we present Matchotter -- a dedicated finite-temperature module natively integrated into the Matchete package -- which automates this matching process up to one-loop order for generic Lagrangians. By adapting modern functional matching techniques to the finite-temperature formalism, Matchotter efficiently extracts the low-energy EFT directly from the thermal path integral. Furthermore, the module fully automates supersoft matching, where the temporal gauge bosons, which acquire a Debye mass during the dimensional reduction process, are integrated out. We outline the underlying architecture of the program and demonstrate its capabilities across a range of models, including the Standard Model Effective Field Theory (SMEFT).

    hep-ph6 citations
24. 24*

    Cosmic-Ray Signatures of Annihilating and Semi-Annihilating Dark Matter via One-Step Cascades

    Francesco D'Eramo🇮🇹 · Silvia Manconi🇫🇷 · Tommaso Sassi🇮🇹

    We present a framework in which three classes of dark matter number-changing processes can affect both the relic abundance via thermal freeze-out in the early universe and the generation of indirect cosmic-ray signals today. These processes are: (i) direct annihilations into Standard Model final states; (ii) annihilations into metastable on-shell mediators that subsequently decay into Standard Model particles; (iii) semi-annihilation processes featuring a dark matter particle in the final state, accompanied by a metastable mediator. A central element of our analysis is the systematic inclusion of semi-annihilation alongside the more commonly considered channels. This setup is largely model-independent, as we only assume the presence of one or more of these processes with unsuppressed $s$-wave contributions. We analyze representative benchmarks for the dominant decay modes of the mediator and show how the resulting injection spectra for $\gamma$ rays, neutrinos, and cosmic-ray antimatter vary with the relative importance of the three classes of processes. As an application, we evaluate the observable $\gamma$-ray fluxes from dwarf spheroidal galaxies in the GeV-TeV window. Finally, we provide explicit model realizations in which multiple processes coexist, and discuss how their interplay shapes indirect detection signatures. Our results provide a consistent connection between early-universe dynamics and present-day observables, revealing distinctive features that arise when multiple dark matter processes contribute simultaneously.

    hep-phastro-ph.COastro-ph.HEJCAP(2026)·0 citations
25. 25*

    Quark hierarchies and CP violation from the Siegel modular group

    M. Carducci🇮🇹 · D. Meloni🇮🇹 · M. Parriciatu🇮🇹 · J. T. Penedo🇮🇹

    We investigate theories of flavour based on genus $g=2$ modular invariance and analyze how fermion mass hierarchies can be generated in this context, in the vicinity of invariant points or regions in moduli space where a residual symmetry is preserved. We apply this mechanism of modular proximity-induced hierarchies to the quark sector, with the vacuum expectation values of the moduli being the only sources of spontaneous breaking of the flavour and CP symmetries. We present a benchmark model where quark mass hierarchies and CP violation are explained, with mass ratios vanishing in the symmetric limit, and quark mixing is reproduced. In this model, the values of the moduli turn out to be close to special values such as ${\tau }_1\simeq \omega$ and ${\tau }_2\simeq \omega ,i$.

    hep-phhep-th1 citation
26. 26*

    Physics-Informed Neural Networks for Solving Two-Flavor Neutrino Oscillations in Vacuum and Matter Environments for Atmospheric and Reactor Neutrinos

    Srinivasan T. · Kalyani Desikan

    Neutrino oscillations provide crucial insights into fundamental particle physics, with two-flavor approximations effectively describing reactor and atmospheric phenomena. This paper investigates the application of Physics-Informed Neural Networks (PINNs), which have several advantages over traditional solvers. Traditional methods typically depend on mesh-based techniques or dimensionality reduction approaches to solve the governing differential equations for neutrino evolution in vacuum and matter environments. We review the theoretical framework, including vacuum mixing and the Mikheyev-Smirnov-Wolfenstein (MSW) effect in matter, and demonstrate PINN implementations for vacuum and constant-density profiles. This Machine learning based approach for reactor (low-energy) and atmospheric (high-energy) neutrinos shows high precision similar to analytical solutions, with mean squared errors of the order of 10^{-3}~10^{-4}. We have also discussed the robustness of PINNs in solving coupled ODE systems, along with future extensions to three-flavor effects.

    hep-ph0 citations
27. 27*

    Relativistic effects in k-essence

    Didam Duniya (BIUST)🇧🇼 · Isaac Opio (BIUST)🇧🇼 · Bishop Mongwane (Cape Town)🇿🇦 · Hassan Abdalla (NWU and Omdurman)🇿🇦

    Relativistic effects are sensitive to subtle changes in dark energy. These effects grow on very large scales and at high redshifts, which will be the reach of upcoming surveys. We investigate these effects in both the linear and the angular galaxy power spectra in a late-time universe dominated by cold dark matter and k-essence, focusing on three core models (dilaton, tachyon, and DBI scalar fields) and contrasting their predictions with those of the concordance model. By enforcing identical present-day cosmological parameters, we isolate the imprints of k-essence dynamics and perturbations on very large scales. We found that relativistic corrections dominate on very large scales and grow with redshift, but are largely insensitive to k-essence microphysics in Fourier space, leading to strong degeneracies among the models. However, in the angular power spectrum, where line-of-sight integrals are naturally included, relativistic effects are significantly amplified, yielding better sensitivity to clustering k-essence. In particular, the tachyon exhibits clear deviations across multipoles and redshifts, with distinct imprints in the Doppler and the combined (velocity and gravitational) potentials contributions. Furthermore, our results show that neglecting relativistic corrections can lead to systematic misestimation of deviations of k-essence from the cosmological constant. Our results show the relativistic angular galaxy power spectrum as a more consistent and robust probe of ultra-large-scale physics. These findings underscore the need for full relativistic modelling in next-generation surveys that are targeting horizon-scale modes, where the imprint of non-standard dark energy is most pronounced.

    ↳ astro-ph.COgr-qchep-ph1 citation
28. 28*

    Relativistic frequency shifts in gravitational waves from axion clouds

    Takuya Takahashi🇯🇵

    Superradiant instability of ultralight bosons can produce clouds around rotating black holes, whose continuous gravitational wave (GW) emission is a promising observational target. Precise predictions of the signal frequency and its evolution are essential for detecting such continuous GWs. For axions, self-interactions can populate multiple superradiant modes via nonlinear couplings, and GW emission can occur through various channels. To calculate the frequency shifts of GWs emitted through these channels, we employ relativistic perturbation theory based on a bilinear form. We apply this framework to self-interaction effects for the first time, and also revisit the treatment of the self-gravity contribution. Our results provide a simple and unified framework for calculating frequency shifts, including cases in which multiple modes are excited, and are relevant for next-generation GW observations.

    ↳ gr-qcastro-ph.COhep-phPRD(2026)·1 citation
29. 29*

    Reconstructing the full kinematic dependence of GPDs from pseudo-distributions

    Hervé Dutrieux🇫🇷 · Robert G. Edwards🇺🇸 · Joe Karpie🇺🇸 · Cédric Mezrag🇫🇷 · Christopher Monahan🇺🇸 · Kostas Orginos🇺🇸 · Anatoly Radyushkin🇺🇸 · David Richards🇺🇸 · Eloy Romero🇺🇸 · Savvas Zafeiropoulos🇫🇷

    We propose a reconstruction of the full $(x,\xi ,t)$ dependence of unpolarized isovector proton generalized parton distributions (GPDs) $H^{u-d}$ and $E^{u-d}$ from lattice QCD data in the pseudo-distribution formalism. For the first time, we extract double distributions (DDs) directly from lattice data, enforcing therefore an important property of GPDs linked to Lorentz symmetry. We use the flexible framework of multidimensional Gaussian process regression to regularize the inverse problem and present an assessment of the impact of model dependence on the systematic uncertainty. Our lattice ensemble corresponds to a pion mass $m_{\pi }=358$~MeV and a lattice spacing $a=0.094$~fm. We use larger hadron momenta, up to 2.7~GeV, and kinematic coverage compared to our previous computations and extract additional skewness-dependent moments of the GPD.

    ↳ hep-lathep-ph6 citations
30. 30*

    Effective field theory interpretation of ATLAS measurements involving the Higgs boson, electroweak bosons and the top quark

    ATLAS Collaboration

    Wilson coefficients in dimension-six effective field theory are constrained in a combined fit to several ATLAS measurements. These inputs probe Higgs-boson processes across multiple production and decay modes, di-Higgs signatures in the $b\bar{b}\gamma \gamma$ and $b\bar{b}\tau \tau$ final states, $WW$ and $WZ$ diboson signatures, electroweak $Zjj$ final states, high-mass Drell-Yan interactions, and $t\bar{t}$ events in both resolved and boosted topologies. Precision electroweak observables from LEP, SLD, and ATLAS are also included. A total of 48 parameters, including individual Wilson coefficients in the Warsaw basis and linear combinations of Wilson coefficients, are constrained simultaneously. Constraints on two-Higgs-doublet models and heavy-vector-boson models are also obtained by matching a relevant sub-set of the results with their parameters. This combined fit provides the most comprehensive effective field theory interpretation of experimental data by the ATLAS Collaboration to date. No significant deviations from the Standard Model are observed.

    ↳ hep-exhep-phJHEP(2026)·2 citations
31. 31*

    Quantum-information diagnostics of cosmological perturbations with nontrivial sound speed in inflation

    Shi-Cheng Liu🇨🇳 · Lei-Hua Liu🇨🇳 · Bichu Li🇨🇳 · Hai-Qing Zhang🇨🇳 · Peng-Zhang He🇨🇳

    In this work, we systematically investigate the quantum-information diagnostics of cosmological perturbations with a nontrivial sound speed, utilizing a normalized open two-mode squeezed-state framework. Rather than introducing new observables, our analysis focuses on how a modified sound speed dynamically reshapes the Schrödinger evolution of the squeezing parameters ($r_k$ and ${\varphi }_k$). We demonstrate how these dynamical changes are inherited by the reduced density matrix of the observable sector. By employing a sound-speed-resonance parametrization, we derive and evaluate the purity, von Neumann entropy, Rényi entropies, and logarithmic negativity. To overcome the intrinsic multiscale stiffness of the post-inflationary equations, we introduce a bounded variable $x=\tanh r_k$ as a partial regularization, which enables reliable numerical simulations exclusively within the inflationary regime. Our numerical results reveal that a nontrivial sound speed significantly suppresses the purity of the reduced state, indicating enhanced effective mixedness. Simultaneously, it strongly amplifies and modulates both the entropic and entanglement diagnostics. More precisely, a nontrivial sound speed postpones the onset of classicality by modulating the decoherence process. Ultimately, we show that a nontrivial sound speed leaves distinct and identifiable quantum-information signatures within the entanglement structure of the early universe.

    ↳ gr-qcastro-ph.COhep-phhep-th+15 citations
32. 32*

    Agentic-AI Detector Co-design and Optimization in Vertically-Integrated Differentiable Full Simulations

    Wonyong Chung🇺🇸 · Qibin Liu🇺🇸 · Liangyu Wu🇺🇸 · Julia Gonski🇺🇸

    We present the first implementation of AI agents into the design and optimization of detectors in high-energy physics experiments via a bi-level optimization framework that vertically integrates detector geometry, front-end digitization, and high-level reconstruction algorithm parameters in differentiable full simulations. Using the example of a dual-readout, segmented crystal EM calorimeter with a baseline resolution of $3\%/\sqrt{E}$, we investigate the capabilities and value propositions of AI agents in the identification and reduction of key detector parameters and in the nonlinear traversal of design space. We find that frontier LLM reasoning-models today, without being given additional experiment-specific context, are able to effectively execute complex workflows and proactively suggest generic but relevant avenues for further study or improvement. Here, we demonstrate an AI agent's ability to find an optimal design point amidst three competing performance criteria, showing that effective integration of agents into the complex workflows of frontier research areas can yield higher performance for key physics goals while reducing labor and compute. This study establishes the foundation for a future demonstration of the first fully AI-designed detector for future scientific facilities.

    ↳ physics.ins-dethep-exhep-ph1 citation
33. 33*

    High-energy photon hologram of a photon gas

    P.O. Kazinski🇷🇺 · A.A. Sokolov🇷🇺

    The photon hologram of a one-particle density matrix of a photon gas is derived including the case where the energy of a probe photon is above the electron-positron pair creation threshold. The explicit expressions for the holograms of a photon gas with one-particle density matrix in the form of a single Gaussian and of coherent and incoherent lattices of Gaussians are obtained. The conditions for resonant cones of coherent scattering by coherent and incoherent lattices are found. These conditions turn out to be different. The explicit expression for the dielectric susceptibility tensor of a photon gas and of a single photon prepared in arbitrary quantum states are derived on the probe photon mass-shell. It is established that a photon gas and a single photon behave in coherent photon scattering as a medium with linear and circular birefringence. This medium is transparent below the electron-positron creation threshold and is absorbing otherwise. In the high-energy limit, $\sqrt{s}\gg 2m$, it has the dielectric susceptibility tensor of a birefringent plasma except for a slow logarithmic scaling. It is shown that, for the probe photon energies of order $1$ GeV and higher, the energies of target photons of order $1$ eV and higher, and the photon gas density such that the classical intensity parameter is of order unity, the hologram of the photon gas can be measured with existing experimental facilities.

    ↳ hep-thhep-phPRD(2026)·0 citations
34. 34*

    D-branes and fractional instantons on a twisted four torus: the moduli space as an N=2 supersymmetric Higgs branch

    Erich Poppitz🇨🇦

    We study self-dual instantons of topological charge $Q=r/N$, for any natural $r$, in $SU(N)$ Yang-Mills theory on a four torus with 't Hooft twists, by embedding them into worldvolume theories of $D$-branes. To study their moduli, we construct the wrapped intersecting brane configurations dual to general constant field strength instanton backgrounds. We show that, locally, the moduli space is identified with the Higgs branch of an $N=2$ supersymmetric theory. This parameterization of the moduli space is equivalent to one recently found in field theory, but is obtained with significantly less effort and has manifest hyper-Kähler structure. Our hope is that combining different perspectives on instantons on the twisted torus will help understand the still unknown global structure of the moduli space for general solutions with $Q=r/N$ as well as the nature of instantons with all moduli turned on -- when some $Q<1$ and all $Q\ge 1$ instantons become space-time dependent. For integer $Q$, these are expected to match the ADHM solution in an appropriately taken infinite volume limit.

    ↳ hep-thhep-lathep-phJHEP(2026)·1 citation

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.