Mon·Jan 26, 2026Monday·January 26, 2026

1. 01*

   UV cut-off of the Standard Model and proton decays

   Ryuichiro Kitano🇯🇵 · Shohei Okawa🇰🇷

   Non-observation of proton decays as well as the smallness of the neutrino masses can naturally be explained by the accidental baryon and lepton number symmetry in the Standard Model, where the approximate symmetries are a consequence of the absence of the baryon or lepton number violating operators at the renormalizable level. The neutrino masses at sub-eV scales can be explained by the presence of the dimension-five term, $\ell \ell HH/\Lambda$, in the Lagrangian, suggesting that a more fundamental theory takes over beyond the energy scale $\Lambda$. We consider the possibility that the theory above the scale $\Lambda$ generates general higher dimensional operators with the flavor structure implied by the Yukawa interactions in the Standard Model. Such a set-up can be realized, for example, in the composite Higgs scenario with partial compositeness of fermions. The fermion masses and the neutrino masses are explained for $\Lambda \gtrsim 10^{11}$GeV. The lifetime of proton in this scenario is, interestingly, consistent with the observed event of the $p\to {\pi }^0{\mu }^{+}$ decay at the Super-Kamiokande experiment. The Hyper-Kamiokande experiment should see a large number of events soon after the data taking, if the event observed by the Super-Kamiokande is due to the real proton decay.

   hep-phhep-ex1 citation
2. 02*

   Axial Anomaly, entanglement and polarization

   O.V. Teryaev🇷🇺

   The (pion) decays controlled by axial anomaly imply the specific entanglement between photons having also the counterparts for classical electromagnetic waves. This is also a specific case of Eisnstein-Podolsky-Rosen-Bohm-Aharonov effect. The absence of causality and non-locality in (angular) momentum conservation is manifested, being especially clear for the generalization to the case of time rather than space separation corresponds to the polarization of dileptons described by time-like pion transition formfactors which may be studied experimentally. The similar decays in external magnetic field manifest the interplay with vacuum conductivity in external magnetic field and longitudinal polarization of vector mesons observed in heavy-ion collisions.

   hep-phnucl-thquant-phPoS(2026)·0 citations
3. 03*

   Extraction of the color dipole amplitude with physics-informed neural networks

   Wei Kou🇨🇳 · Xurong Chen🇨🇳

   The process-independence of the color dipole amplitude is a cornerstone of high-energy Quantum Chromodynamics (QCD). However, standard phenomenological approaches typically rely on rigid parametric ansatzes and often require ad-hoc geometric adjustments to reconcile inclusive and diffractive measurements. To resolve this tension, we introduce Physics-Informed Neural Networks (PINNs) employing a ``Teacher--Student'' strategy. The physics-based momentum-space Balitsky-Kovchegov evolution dynamics act as the ``Teacher,'' constraining the solution manifold, while the network ``Student'' is refined against inclusive HERA $F_2$ data. This approach extracts a model-independent dipole amplitude without assuming initial states. Strikingly, we demonstrate that this amplitude -- without parameter retuning or geometric rescaling -- successfully predicts the absolute normalization and kinematic dependence of exclusive $J/\psi$ photoproduction cross-sections. This parameter-free prediction of the saturation dynamics provides promising evidence for the process-independence of the gluon saturation scale and establishes PINNs as a transformative paradigm for uncovering non-perturbative QCD structures.

   hep-phPLB(2026)·5 citations
4. 04*

   PanopTag: Simultaneously Tagging All Jets in a Particle Collision Event

   Umar Sohail Qureshi🇺🇸 · Brendon Bullard · Ariel Schwartzman🇺🇸

   Jet tagging, identifying the origin of jets produced in particle collisions, is a critical classification task in high-energy physics. Despite the revolutionary impact of deep learning on jet tagging over the past decade, the paradigm has remained unchanged. In particular, jets are classified independently, one at a time. This single-jet approach ignores correlations, overlaps, and wider event context between jets. We introduce PanopTag, a new paradigm for jet tagging that departs from traditional single-jet tagging approaches. Rather than classifying jets independently, PanopTag simultaneously tags all jets by employing an encoder-decoder architecture that uses jet kinematics as queries to cross-attend to particle flow object embeddings. We evaluate PanopTag on heavy-flavor $(b/c)$-tagging and demonstrate remarkable performance improvements over state-of-the-art single-jet baselines that are only accessible by exploiting event-level features and correlations between jets.

   hep-phphysics.data-an0 citations
5. 05*

   Feasibility Study of Lepton Number Violation in Rare $B$ and $K$ Meson Decays

   Motoi Endo🇯🇵 · Kåre Fridell🇯🇵 · Sho Iwamoto🇹🇼 · Yushi Mura🇯🇵 · Kei Yamamoto🇯🇵

   We study lepton-number-violating interactions at dimension seven in the Standard Model effective field theory that contribute to the meson decays $B\to K\nu \nu$ and $K\to \pi \nu \nu$. Such interactions could washout the baryon asymmetry of the Universe and also contribute to the neutrinoless double beta decay, even though the interactions involve a change in down-type quark flavors. We clarify conditions under which excesses in meson decay rates over the Standard Model predictions can be successfully observed. We also show that, although these interactions contribute to neutrino masses at the two-loop level, the Weinberg operator can be introduced consistently without spoiling the scenario.

   hep-phJHEP(2026)·2 citations
6. 06*

   Effective Field Theory Description of Light Dilaton

   Qing-Hong Cao🇨🇳 · Jian-Nan Ding🇨🇳 · Bing-Hui Ge🇨🇳 · Hao Sun🇨🇳 · Jiang-Hao Yu🇨🇳

   Dilatons, the CP-even pseudo-Nambu-Goldstone bosons arising from spontaneous scale symmetry breaking, offer a compelling alternative to axion-like particles (ALPs) yet lack a comprehensive low-energy framework. We address this by constructing a systematic effective field theory (EFT) for the dilaton based on a manifestly scale-invariant regularization scheme. This approach derives universal linear couplings to the trace anomaly while preserving consistent renormalization group evolution. We establish a hierarchical EFT tower connecting the ultraviolet conformal sector to the infrared, encompassing the dilaton-extended SMEFT, low-energy EFT up to dimension-7, and a chiral Lagrangian describing meson and baryon interactions. We perform a comprehensive phenomenological analysis across two distinct mass regimes, where dilaton manifests as either conventional particle or wave-like particle. For MeV-scale dilatons behaving as conventional particles, we obtain constraints from LHC production, semi-invisible $B$- and $K$-meson decays, and supernova cooling. For ultralight dilatons acting as dark matter, we project sensitivities for atomic clocks and atom interferometers. This unified EFT framework would pave the way for extended phenomenological studies across the full mass spectrum of the light dilaton.

   hep-phCPC(2026)·2 citations
7. 07*

   Description of Charged\text{-}Particle Multiplicity Distributions in High\text{-}Energy Proton\text{-}Proton Collisions Based on a Two-Component Model and Examination of Parton Distribution Functions

   Zhixiang Yang🇨🇳 · Jianhong Ruan🇨🇳

   High-energy proton-proton collisions at the LHC offer a stringent test of Quantum Chromodynamics (QCD) in the small-$x$, gluon-dominated regime. This study focus on a minimal, gluon-driven framework to describe the charged-particle multiplicities and their pseudorapidity densities in high energy collisions. The two-component model taken here includes the hard gluon-gluon fusion process and the soft quark recombination process, which directly relates to both integrated and unintegrated parton distributions. We begin by evolving Parton Distribution Functions (PDFs) using the Modified Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (MD-DGLAP) equations. These PDFs are then converted into unintegrated PDFs (UPDFs) via the Kimber-Martin-Ryskin (KMR) scheme. The resulting PDFs and UPDFs are incorporated into the two-component model to predict the charged-particle pseudorapidity density $\left(1/N_{\mathrm{ev}}\right)d{N}_{\mathrm{ch}}/d\eta$ in $pp$ collisions at LHC energies. Our predictions are compared to the data from the ATLAS experiment, revealing that the model effectively captures the features of the observed pseudorapidity distributions, despite its simplicity. Within this framework, the gluon-gluon fusion processes are found to dominate particle production for $\sqrt{s}\ge 900\mathrm{GeV}$.These findings provide phenomenological support for MD-DGLAP-based PDFs and the associated small-$x$ gluon dynamics. Furthermore,a comparative analysis of results from alternative PDF sets--including CTEQ, MSHT, NNPDF, HERAPDF, and GRV--is performed, with particular focus on examining their consistency with the relative shapes of experiment data in the small-$x$ region.

   hep-ph0 citations
8. 08*

   Flavour-Changing Neutral Current Top Decays in the Three Higgs Doublet Model

   Baradhwaj Coleppa🇮🇳 · Benjamin Fuks🇫🇷 · Akshat Khanna🇮🇳

   We study flavour-changing neutral current decays of the top quark in the democratic Three Higgs Doublet Model featuring a $Z_3$-symmetric scalar potential and Natural Flavour Conservation. In this framework, while such processes are absent at tree-level, the extended scalar sector induces new one-loop contributions to rare top decays. We compute the branching ratios for processes of the form $t\to qX$ (with $q=u,c$ and $X$ denoting a boson of the model), and explore the viable regions of the parameter space under theoretical consistency conditions and current experimental constraints. Several alignment-limit scenarios corresponding to different hierarchies among the CP-even Higgs states are analysed, and we find that the predicted branching ratios can significantly exceed their Standard Model expectations while remaining consistent with existing limits. In particular, we identify scenarios with light non-standard scalars that can lead to rates within the projected sensitivity of the High-Luminosity LHC. Our results therefore highlight rare top decays as a promising probe of the extended scalar sector of the Three Higgs Doublet Model.

   hep-ph3 citations
9. 09*

   Thermodynamic geometry in hadron resonance gas model at real and imaginary baryon chemical potential and a simple sufficient condition for quark deconfinement

   Riki Oshima🇯🇵 · Hiroaki Kouno🇯🇵 · Motoi Tachibana🇯🇵 · Kouji Kashiwa🇯🇵

   The thermodynamic geometry of the hadron resonance gas model with (without) excluded volume effects (EVE) of baryons is investigated. The case with imaginary mu, where mu is the baryon chemical potential, is investigated as well as the one with real mu. We calculate the scalar curvature R and use the R=0 criterion to investigate the phase structure in the mu^2-T plane where T is the temperature. The curve on which R=0 continues analytically from the imaginary mu region, where the lattice QCD is feasible, to the real mu one. In the presence of EVE, there are rich phase structures in the large real mu region as well as the Roberge-Weiss like region where mu is imaginary and a singularity appears, while there is no phase structure in the large real $\mu$ region in the absence of EVE. The limitation temperature of the baryon gas is also obtained by using the baryon number fluctuation. The LQCD predicted critical point locates almost on the curve of the limitation temperature we determined. A simple empiric sufficient condition, n_B>1/(2v_B)$, is obtained for the quark deconfinement in the large real mu region, where n_B and v_B are the net baryon number density and the volume of a baryon, respectively.

   hep-phhep-exhep-latnucl-ex+1PRD(2026)·1 citation
10. 10*

    The Scattering Algebra of Physical Space: Squared Massive Constructive Amplitudes

    Moab Croft🇺🇸 · Neil Christensen🇺🇸

    The Algebra of Physical Space (APS) is used to explore the Constructive Standard Model (CSM) of particle physics. Namely, this paper connects the spinor formalism of the APS to massive amplitudes in the CSM. A novel equivalency between traditional CSM and APS-CSM formalisms is introduced, called the Scattering Algebra (SA), with example calculations confirming the consistency of results between both frameworks. Through this all, two significant insights are revealed: The identification of traditional CSM spin spinors with Lorentz rotors in the APS, and the connection of the CSM to various formalisms through ray spinor structure. The CSM's results are replicated in massive cases, showcasing the power of the index-free, matrix-free, coordinate-free, geometric approach and paving the way for future research into massless cases, amplitude-construction, and Wigner little group methods within the APS.

    hep-phAdv.Appl.Clifford Algebras(2026)·1 citation
11. 11*

    Cosmic-ray-electron boosted light dark matter: Implications of LZ 2025 data

    Sk Jeesun🇨🇳 · Anirban Majumdar🇮🇳

    Current multiton detectors put stringent constraints on the GeV-scale galactic dark matter, pushing the allowed cross section almost toward the neutrino fog, yet remain mostly insensitive to the light dark matter. Cosmic rays can upscatter the nonrelativistic halo dark matter particles, making a subpopulation of them gain sufficient kinetic energy to be discernible in current direct search experiments. In this work, we explore this alternate strategy to probe sub-MeV electrophilic dark matter boosted by cosmic rays with the latest data of LZ 2025 (WS2024 run). We also incorporate the attenuation effect on the boosted dark matter flux during its propagation through the Earth and perform a full numerical treatment to obtain the resulting event rate. Our result shows LZ 2025 data improve the constraint on the MeV scale dark matter by almost $\sim \mathcal{O}(1)$ compared to the previous XENONnT limit for the energy-independent cross section. Using realistic energy-dependent cross sections, we also analyze such a scenario, where the associated mediator mass plays a crucial role in governing the event rate and hence the expected limits too. With energy-dependent cross sections, our obtained limits also remain stronger than the existing constraints from the XENONnT experiment. Even compared to the limits from neutrino detectors with much larger target masses, LZ 2025 can place stringent constraints in certain regions of the mediator parameter space, particularly in the light-mediator regime, excluding previously unexplored regions.

    hep-phastro-ph.COhep-exPRD(2026)·3 citations
12. 12*

    NLO QCD corrections to the electroweak production of a Higgs boson pair in the quark-antiquark channel

    Marco Bonetti🇩🇪 · Gudrun Heinrich🇩🇪 · Philipp Rendler🇩🇪 · William J. Torres Bobadilla🇬🇧

    Higgs boson pair production in the massless quark-antiquark channel proceeds at leading order (LO) via electroweak boson loops. We calculate the next-to-leading order QCD corrections to this process. For the corresponding two-loop amplitudes, an analytic representation has been achieved. Even though the size of this contribution at the level of total cross sections is below 1% compared to the LO gluon channel, the effect on differential observables can be in the 10% range and therefore this contribution should be taken into account when comparing to LHC data.

    hep-phhep-thJHEP(2026)·4 citations
13. 13*

    Tribute to Tullio Bressani, Bogdan Povh and Toshimitsu Yamazaki

    Avraham Gal🇮🇱

    In this HYP2025 talk I pay tribute to Tullio Bressani (1940-2024), Bogdan Povh (1932-2024) and Toshimitsu Yamazaki (1934-2025), all of whom made lasting contributions to shaping up Strangeness Nuclear Physics. Yoshinori Akaishi's (1941-2025) record is also noted.

    ↳ nucl-thhep-phnucl-exphysics.hist-ph0 citations
14. 14*

    Compatibility of recent $\mathcal{S}=-2$ emulsion events

    Avraham Gal🇮🇱

    We question the compatibility of recent $\mathcal{S}=-2$ hypernuclear assignments of J-PARC E07 ${\Xi }^{-}$-capture emulsion events with assignments deduced from other experiments.

    ↳ nucl-thhep-phnucl-ex0 citations
15. 15*

    When Primordial Black Holes Absorb During the Early Universe

    Md Riajul Haque🇨🇳 · Rajesh Karmakar🇨🇳 · Yann Mambrini🇫🇷

    We study the evolution of primordial black holes (PBHs) formed in the early universe in the presence of a surrounding thermal bath. By incorporating the effects of thermal absorption, we show that PBHs can undergo significant mass growth, leading to extended lifetimes and substantial deviations from the standard Hawking evaporation scenario. We find a critical collapse efficiency, ${\gamma }_{\mathrm{c}}\simeq 0.395$, above which the PBH mass grows without bound. This correction has profound implications for both PBH-induced reheating and dark matter (DM) production. Specifically, we find that the reheating temperature can be suppressed, and the DM parameter space for the PBH reheating scenario can undergo $\mathcal{O}(10)$-$\mathcal{O}(10^4)$ corrections, depending on the PBH formation mass and collapse efficiency. Moreover, our results significantly shift the parameter space in which PBHs can account for the entirety of the DM. To the best of our knowledge, this is the first comprehensive phenomenological study to incorporate thermal absorption into PBH evolution and quantify its impact on cosmological observables.

    ↳ astro-ph.COhep-ph8 citations
16. 16*

    Coupled-channel approach to isotensor $\pi \pi \pi$ scattering from lattice QCD

    Yuchuan Feng🇺🇸 · Chris Culver🇬🇧 · Michael Döring🇺🇸 · Maxim Mai🇺🇸 · Andrei Alexandru🇺🇸 · Frank X. Lee🇺🇸

    The quest to understand three-body dynamics from first-principle QCD includes the study of non-resonant and resonant systems. The isospin $I=2$ system is of particular interest having no three-body resonance but featuring a resonance in a sub-channel, while also being a coupled-channel problem. In this study, we calculate the finite-volume spectrum from lattice QCD at two different pion masses, map the amplitude to the infinite volume through a generalized Finite-Volume Unitarity (FVU) three-body quantization condition, investigate the limit of a narrow $\rho$, and compare with an effective Lagrangian prediction at leading order. Chiral extrapolations between different pion masses are performed.

    ↳ hep-lathep-phnucl-thPRD(2026)·6 citations
17. 17*

    NO LESS: Novel Opportunities for Light Exotic Searches at the SPS

    Babette Döbrich🇩🇪 · Jan Jerhot🇩🇪 · Karim Massri🇬🇧 · Jonathan L. Schubert🇩🇪 · Tommaso Spadaro🇮🇹

    A powerful way to test models with feebly interacting particles in the MeV to GeV mass range is through proton beam-dump experiments. In this paper, we compare the current sensitivity of CERN's NA62 experiment running in beam-dump mode with that of a hypothetical experiment using the same detectors in a future CERN ECN3 beam-dump facility. When optimising such an experiment, the geometric setup is particularly relevant for the specific new-physics scenario under study, since different production mechanisms can generate different angular distributions of new particles. We show that even the most minimalistic reconfiguration of the existing NA62 experiment's detectors can already provide a very competitive sensitivity and collect data immediately after the beam is available.

    ↳ hep-exhep-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.