Thu·May 21, 2026Thursday·May 21, 2026

1. 01*

   First mass determination of electroweak vortex rings in the Standard Model

   Dan Zhu🇨🇳 · Qingyue Zhang🇨🇳 · Khai-Ming Wong🇲🇾 · Xurong Chen🇨🇳

   We report the first rigorous evaluation of the physical mass of electroweak vortex rings, establishing precise values of 18.01 and 26.80 TeV for solutions characterized by different winding numbers. Analysis of the internal structure reveals that repulsive interactions shape the geometry of these configurations, while complex current distributions lead to a neutral analogue of Ampere's circuital law, suggesting a corresponding self-stabilizing pinch mechanism. These findings set the energy scales for the potential observation of such configurations at future colliders and offer a framework for understanding topological structures in the Standard Model.

   hep-phhep-th0 citations
2. 02*

   The Alternative Left-Right Scenario: Unitarity, Vacuum Stability and RG Evolution

   Hrishikesh Deka🇮🇳 · Avnish🇮🇳 · Sumit K. Garg🇮🇳 · Poulose Poulose🇮🇳

   We study the theoretical constraints on the scalar sector of the Alternative Left-Right Model (ALRM), an $E_6$-motivated extension of the Standard Model based on the gauge group $\mathrm{SU}(3{)}_c\otimes \mathrm{SU}(2{)}_L\otimes \mathrm{SU}(2{)}_{R^{\prime }}\otimes \mathrm{U}(1{)}_{B-L}$, supplemented by a global $\mathrm{U}(1{)}_S$ symmetry. We derive the complete set of tree-level perturbative unitarity constraints on the model, resulting in 14 independent conditions on the quartic scalar couplings. When combined with the boundedness-from-below conditions and the requirement of positive-definite scalar mass-squared eigenvalues, these constraints are found to be complementary, with their simultaneous imposition yielding significantly more stringent restrictions on the parameter space than either set alone. We then perform a one loop renormalization group analysis, evolving the model parameters from the electroweak scale up to a high energy cut-off scale, and requiring that the vacuum stability, the unitarity, and the perturbativity conditions are preserved throughout. The renormalisation group evolution is found to restrict the allowed parameter space considerably beyond the tree-level bounds, with the constraints on the quartic couplings becoming more stringent as the cut off scale is raised. Consequently, the physical scalar masses in the model acquire upper bounds. For the right-hand symmetry breaking scale, $v_R=10$ TeV and requiring theoretical consistency up to $10^{16}$ GeV, we obtain $m_{H_1^{\pm }}\lesssim 6.5$ TeV, $m_{H_2^{\pm }}\lesssim 1.5$ TeV, and $m_{H_1^0}\simeq m_{A_1}\lesssim 1.3$ TeV, with all bounds scaling with $v_R$. These findings offer a predictive and falsifiable framework for searches of the extended Higgs sector of the ALRM at the current and future collider experiments.

   hep-phPRD(2026)·0 citations
3. 03*

   VLQBounds: Confronting Vector-Like Quark Models with LHC Searches

   A. Arhrib🇲🇦 · R. Benbrik🇲🇦 · M. Boukidi🇵🇱 · M. Ech-chaouy🇲🇦 · S. Moretti🇬🇧 · K. Kahime🇲🇦 · K. Salime🇲🇦 · Q.S. Yan🇨🇳

   We present VLQBounds, a public, data-driven Python framework for testing Vector-Like Quark (VLQ) scenarios against Large Hadron Collider (LHC) exclusion limits from ATLAS and CMS. The framework incorporates public results on both pair and single VLQ production and supports the main parameterisations used in experimental interpretations, including mass-mixing, mass-coupling, and mass-width representations. For each parameter point, the predicted cross-section or effective coupling is compared channel by channel to the corresponding observed and expected experimental limits through interpolation over machine-readable grids. The most sensitive analysis is automatically identified and a 95\% Confidence-Level exclusion verdict is returned, together with the observed and expected sensitivity ratios and the metadata needed for reproducible reinterpretation. The modular structure of VLQBounds makes it suitable for fast phenomenological scans, validation of public limits, and future extensions to new collider searches and non-minimal VLQ decay patterns.

   hep-ph2 citations
4. 04*

   Impact of matter effects on the unitarity test of lepton mixing

   Ryuichiro Kitano🇯🇵 · Joe Sato🇯🇵 · Sho Sugama🇯🇵

   Testing the unitarity of the lepton mixing matrix, in a manner analogous to the unitarity tests of the CKM matrix in the quark sector, is an important step toward probing physics beyond the standard three-generation framework. In long baseline neutrino oscillation experiments, the formula of the oscillation probabilities can be written as a sum of terms with various combinations of the mixing-matrix elements, and their coefficients depend differently on energy. By observing the spectral information of long baseline experiments such as T2HK and a future neutrino factory at J-PARC with a ${\nu }_e$ beam, the elements of the mixing matrix can be extracted without assuming a specific parametrization of the mixing matrix. We investigate how such an extraction method can be applied to neutrino oscillations by taking into account matter effects, and discuss how one can test unitarity of the mixing matrix in future long baseline experiments. As a concrete example, we examine the unitarity test by using a four-generation model, where we look at a quantity which should be vanishing in a unitary model. Among possible combinations of measurements, the most powerful test can be provided from the energy spectra of the CP-conjugate appearance channels ${\nu }_{\mu }\to {\nu }_e$ and ${\bar{\nu }}_{\mu }\to {\bar{\nu }}_e$ at T2HK, as well as from the T-conjugate pair ${\nu }_{\mu }\to {\nu }_e$ and ${\nu }_e\to {\nu }_{\mu }$ available at neutrino factories.

   hep-phhep-ex0 citations
5. 05*

   The Single Photon Signature of a Light Long-lived Neutralino at Remote Detectors at the LHC

   Herbi K. Dreiner🇩🇪 · Julian Günther🇩🇪 · Dominik Köhler🇩🇪 · Apoorva Shah🇩🇪

   We investigate the phenomenology of light long-lived neutralinos in R-parity violating supersymmetric models, focusing on the proposed remote detectors $\text{ANUBIS}$, $\text{CODEX-b}$, $\text{FACET}$, $\text{FASER}$, $\text{FASER2}$, $\text{MAPP}$, $\text{MAPP2}$, and $\text{MATHUSLA}$ at the LHC. We assume the production of the neutralinos at the ATLAS or CMS interaction points via rare scalar meson decays induced by R-parity violating couplings. We study six supersymmetric R-parity violating benchmark scenarios in which the dominant neutralino decay is ${\tilde{\chi }}_1^0\to \gamma +\nu$. For each scenario, we determine the projected search sensitivity at the above listed detectors. Extending previous work focused primarily on $\text{FASER}$ and $\text{FASER2}$, we improve the simulation by taking into account the extended flight path of the parent meson. We find that $\text{ANUBIS}$ provides the best sensitivity to our benchmark scenarios and $\text{FASER}$ the least among the considered experiments, while of course $\text{FASER}$ has already taken data.

   hep-phhep-ex2 citations
6. 06*

   Audible Axion Magnetogenesis: Linking Intergalactic Magnetic Fields and Gravitational Waves

   Christopher Gerlach🇩🇪 · Daniel Schmitt🇩🇪 · Pedro Schwaller🇩🇪

   Identifying dark matter candidates that simultaneously generate multiple observable cosmological signatures is a key goal in connecting particle physics with upcoming observations. Axion-like particles coupled to the Standard Model photon offer a promising framework. In the trapped misalignment mechanism, the onset of axion oscillations is delayed, inducing a period of supercooling in the early Universe. This can lead to exponential production of photon quanta via a tachyonic instability, generating observable gravitational wave signatures. Simultaneously, reheating of the Standard Model plasma produces strong, helical magnetic fields on intergalactic scales. The parameter space most promising for gravitational wave detection yields magnetic field strengths that exceed lower bounds from blazar observations.

   hep-phastro-ph.COastro-ph.HE0 citations
7. 07*

   Spectroscopy of hidden-heavy tetraquark states with $J^{PC}=0^{--}$ in a color-octet configuration

   Bing-Dong Wan🇨🇳 · Jun-Hao Zhang🇨🇳 · Yan Zhang🇨🇳 · Ming-Yang Yuan🇨🇳

   Within the QCD sum-rule framework, we investigate hidden-heavy tetraquark channels with the exotic quantum number $J^{PC}=0^{--}$ using four representative local color-octet--octet interpolating currents. The currents include both vector--axialvector and scalar--pseudoscalar Dirac structures. The operator product expansion is carried out up to dimension-eight condensates. The four diagonal sum rules yield mutually consistent mass estimates in the range $10.8$--$11.1\mathrm{GeV}$ for the hidden-bottom sector and around $4.3$--$4.6\mathrm{GeV}$ for the corresponding hidden-charm sector, with the bottom sector exhibiting the clearest Borel stability. Since local tetraquark currents with the same quantum numbers are related by Fierz rearrangements, the current-dependent results do not by themselves imply four distinct states or uniquely defined internal color structures. We also discuss quantum-number-allowed decay channels and emphasize the absence of the lowest pseudoscalar--pseudoscalar heavy-meson modes for a neutral $0^{--}$ state. The results provide theoretical guidance for future experimental searches at Belle II, LHCb, and BESIII.

   hep-ph2 citations
8. 08*

   Photon-initiated enhancements in the pair production of highly charged coloured particles

   Tanumoy Mandal · Subhadip Mitra🇮🇳 · Rachit Sharma

   Strong interaction is typically assumed to dominate the pair production of heavy coloured resonances at the LHC. However, mixed QCD-QED contributions from gluon-photon ($g\gamma$) initial states become critical for highly charged states. This contribution scales with the square of their electric charges and maximises for particles in the fundamental colour representation. We study this effect for leptoquarks, which are colour-triplet bosons. We demonstrate that tree-level mixed QCD-QED contributions enhance their pair-production rates by up to $\sim 33\%$ for a charge-$5/3$ state, rivalling the size of next-to-leading-order QCD corrections. The asymmetric colour flow of $g\gamma$ fusion affects the radiation pattern, altering jet multiplicities and angular distributions. By recasting the latest ATLAS $\mu \mu jj$ search data, we find that these often-overlooked QED effects systematically strengthen mass exclusion limits, establishing a necessary precision standard for bounding highly charged coloured states.

   hep-phhep-ex0 citations
9. 09*

   Comprehensive study of hidden charm pentaquarks with an improved unitarization method

   E.E. Garcia-Gonzales🇪🇸 · V.K. Magas🇪🇸 · A. Ramos🇪🇸

   This work investigates dynamically generated hidden-charm baryon resonances arising from meson-baryon interactions. Using the local hidden gauge formalism, we model the interaction via t-channel vector meson exchange and unitarize the amplitude using the Bethe-Salpeter equation. To address regularization issues, we propose a novel ``hybrid loop function'' scheme that eliminates the unphysical poles -- common artifacts in cutoff or dimensional regularization -- while keeping the predictions of physical states. Consequently, the model successfully reproduces six experimentally known hidden-charm pentaquarks as well as earlier theoretical results, and predicts new states in the S=-1, I=1 sector.

   hep-ph2 citations
10. 10*

    System-size dependence of the $D^0$--$D_s^{+}$ flow splitting from early $D_s^{+}$ formation at $\sqrt{s_{NN}}=5.36$~TeV

    Hui Du🇨🇳 · Xiao-Wei Hao🇨🇳 · Wei Dai🇨🇳 · Jiaxing Zhao🇩🇪 · Ben-Wei Zhang🇨🇳 · Enke Wang🇨🇳

    We investigate the elliptic-flow splitting between prompt $D^0$ and $D_s^{+}$ mesons within a heavy-quark transport framework with sequential hadronization, in which $D_s^{+}$ forms at $1.2T_c$ and $D^0$ at $T_c$. We present predictions for the $p_T$-differential $v_2$ and $D_s^{+}/D^0$ yield ratio in O--O $0$--$20\%$ collisions at $\sqrt{s_{NN}}=5.36$~TeV, where preliminary ALICE data are available. The sequential scenario reproduces the observed $v_2(D^0)>v_2(D_s^{+})$ ordering and predicts an enhanced $D_s^{+}/D^0$ ratio at low $p_T$, whereas a simultaneous baseline yields the opposite ordering. Decomposing the hadronic splitting into its partonic components, we show that the $v_2$ ordering is driven by the late-stage flow accumulated by $D^0$-parent charm quarks during the $1.2T_c\to T_c$ interval, with hadronic rescattering essential to preserve the signal in small systems. A systematic scan across nine collision configurations spanning O--O and Pb--Pb centralities reveals a universal linear scaling between the hadronic splitting and the partonic flow increment accumulated during this window. This establishes the $D^0$--$D_s^{+}$ flow splitting as a hadronization chronometer of the QGP at $\sqrt{s_{NN}}=5.36$~TeV.

    hep-phhep-thPRC(2026)·0 citations
11. 11*

    Self-Consistent Parker Bound on Magnetic Monopoles

    Chen Zhang🇺🇸 · Chun-Yan Jiang🇺🇸 · Nayun Jia🇺🇸 · Xin Zhang🇺🇸

    Magnetic monopoles arise generically in unified theories and offer a natural explanation of charge quantization. Beyond collider searches and cosmic-ray experiments, their flux is constrained by Parker-type bounds requiring galactic magnetic fields to survive monopole energy extraction. We formulate a self-consistent Parker bound anchored in the lowest eigenmode of the galactic mean-field dynamo and convert the resulting limit to the present-day flux. Small-scale turbulent fields both seed this eigenmode and set the monopole velocity via stochastic acceleration before energy extraction from the coherent field. These unavoidable effects substantially modify the standard extended Parker bound at low and intermediate masses, yielding flux limits robust to primordial magnetic fields (PMFs); PMFs strong enough to alter these limits lie in regimes constrained by Ly$\alpha$ data or testable by 21-cm observations and other cosmological probes.

    hep-phastro-ph.COastro-ph.GAgr-qc0 citations
12. 12*

    Impact of Hadronic Resonances on $B\to K^{(\ast )}{\tau }^{+}{\tau }^{-}$ decays

    Guillermo Baltà🇪🇸 · Andreas Crivellin🇪🇸 · Rafel Escribano🇪🇸 · Joaquim Matias🇪🇸 · Martín Novoa-Brunet🇪🇸

    Neutral-current semileptonic $B$ decays are plagued by hadronic resonances across the dilepton invariant-mass squared spectrum, $q^2$. For light leptons, $\ell =e,\mu$, these resonances can be avoided with suitable $q^2$ cuts. This strategy is less straightforward for $\tau$ modes, where missing energy from the $\tau$ decay makes $q^2$ difficult to reconstruct. In fact, while Belle II is able to discriminate between different regions in $q^2$ due to its clean environment, this is not directly possible in a hadronic one. Therefore, the interpretation of $b\to s{\tau }^{+}{\tau }^{-}$ measurements from e.g. LHCb, CMS requires the description of these resonant effects. In this article, we adopt a different strategy by including the resonant contributions (in particular from $\psi (2S)$) into our predictions for $B\to K^{(\ast )}{\tau }^{+}{\tau }^{-}$ decays, instead of avoiding them. We provide predictions for different initial kinematic points ($4m_{\tau }^2,14.18$GeV${}^2$ and $15$GeV${}^2$) that can be convenient for LHCb, CMS and Belle II. For this, we use a data-driven approach based on the LHCb measurements of $B\to K^{(\ast )}{\mu }^{+}{\mu }^{-}$ decays. Including the resonances and integrating over the full $q^2$ range substantially enhances the Standard Model predictions. However, for sufficiently large New Physics, motivated by the current tensions in $R(D^{(\ast )})$ and $B\to K^{(\ast )}\nu \nu$ decays, the short-distance contribution becomes comparable to or even exceeds the resonant one. This highlights two advantages of this strategy: it exploits the additional phase space associated with the resonant regions to probe large New Physics contributions, and it enables the use of hadron-collider data, where the resonances cannot be resolved. We further quantify how including or neglecting the resonances affects the total branching ratio as a function of New Physics contributions and, equivalently, of the experimental precision.

    hep-phhep-exhep-lat0 citations
13. 13*

    $B_c\to {\eta }_c$ form factors at large recoil: SCET analysis and a three-loop consistency check

    Guido Bell🇩🇪 · Philipp Böer🇨🇭 · Thorsten Feldmann🇩🇪 · Dennis Horstmann🇩🇪 · Vladyslav Shtabovenko🇩🇪

    The double-logarithmic series of non-relativistic $B_c\to {\eta }_c$ form factors at large recoil is governed by a coupled set of integral equations, reflecting an intricate interplay between arbitrarily many soft-quark and soft-gluon exchanges. Whereas we previously derived these integral equations with diagrammatic resummation techniques, we analyze the form factors in the limit $m_b\gg m_c\gg {\Lambda }_{\mathrm{QCD}}$ with methods from Soft-Collinear Effective Theory (SCET) in this work. Although the resulting factorization theorem for the so-called soft-overlap contribution is known to be spoilt by endpoint divergences, it can still be used at the level of bare (regularized) quantities at any fixed order in perturbation theory. By calculating the required ingredients, we show that the SCET analysis confirms the predictions of the integral equations up to three-loop order. We also argue that the iterative structure and the intertwined soft-quark and soft-gluon effects can be derived from standard renormalization-group equations of the $B_c$-meson light-cone distribution amplitudes, provided their inverse moments are regularized with an appropriate cutoff.

    hep-ph2 citations
14. 14*

    Statistical sensitivity of neutrinoless double-beta decay exchange mechanism discrimination by tracking experiments

    Jason Detwiler🇺🇸 · Ke Han🇨🇳 · Tao Li🇨🇳

    Reconstruction of the individual energies and the opening angle between the electrons emitted in neutrinoless double-beta decay can probe the nature of the beyond-the-Standard-Model exchange mechanism that underlies the process. Although it is often stated that discrimination of the mechanism would require such measurements to be performed with high statistics, we show that this is not the case. If a single mechanism dominates the process, its discrimination at the 1$\sigma$ level is already achieved with just a few well-reconstructed events; only $\sim$10 such events are required to reach 3$\sigma$-level discovery sensitivity. In the presence of realistic reconstruction uncertainties, this requirement increases to $\sim$25 events, indicating that substantial discrimination power is retained as long as backgrounds remain small. We conclude that the pursuit of tracking detectors for exchange-mechanism discrimination remains valuable even for ``discovery-class'' experiments in which only a few signal counts are expected.

    hep-phhep-ex0 citations
15. 15*

    Cosmological Collider Signatures from Right-Handed Neutrino Loop

    Jingtao You🇨🇳 · Linghao Song🇨🇳 · Chengcheng Han🇨🇳 · Hong-Jian He🇨🇳 · Xingang Chen🇺🇸 · Zhong-Zhi Xianyu🇨🇳

    We study cosmological collider (CC) signatures generated by right-handed neutrino loops in the setup of inflation combined with the neutrino seesaw mechanism. We formulate the inflaton interaction with the right-handed neutrinos through a unique dimension-5 operator respecting shift symmetry, which induces an effective chemical potential in the slow-roll background, leading to helicity-dependent production of right-handed neutrinos and enhancing the CC signatures. The right-handed neutrino is described by a two-component Weyl spinor with a Majorana mass term. Using the Schwinger-Keldysh formalism, we derive a set of seed integrals for fermion propagators of the right-handed Majorana neutrino. With these, we compute the factorized nonlocal contributions to the three-point inflaton correlator generated by the triangle loop of right-handed neutrinos. We show that the chemical potential can substantially soften the heavy-mass Boltzmann suppression and amplify the oscillatory non-Gaussianity signatures associated with the dominant helicity mode. We systematically analyze the spinor structure, the factorization of fermion triangle loop, the loop-momentum integrals and the time seed integrals, which give a controlled computation of the nonlocal contributions to the CC signals of the right-handed neutrinos.

    hep-phastro-ph.COgr-qchep-th7 citations
16. 16*

    Sensitivity of the FCC-ee to axion-like particles at different center-of-mass energies

    Juliette Alimena🇩🇪 · Elnura Bakhishova🇩🇪 · Freya Blekman🇩🇪 · Jannah Darwish Abdelhafiz🇩🇪 · Christina Dorofeev🇩🇪 · Jeremi Niedziela🇩🇪 · Giacomo Polesello🇮🇹 · Anna Przybyl🇩🇪 · Lovisa Rygaard🇩🇪

    The sensitivity of the proposed FCC-ee collider to axion-like particles (ALPs) is investigated at all planned center-of-mass energies, focusing on the case where the ALP couples primarily to electroweak gauge bosons at leading order. We study the associated production of an ALP with a photon, with the ALP decaying in turn to two photons, yielding a three-photon final state. Expected 95% confidence level sensitivities to the ALP-photon coupling are computed for ALP masses between 5 and 320 GeV. In the benchmark model considered, the FCC-ee can probe the ALP-photon coupling down to a few $10^{-6}$ GeV${}^{-1}$ at the Z pole and about $10^{-5}$ GeV${}^{-1}$ at the WW, ZH, and $t\bar{t}$ running stages. The higher-energy running stages extend the mass reach beyond the Z-pole kinematic range, while the Z-pole run provides the best sensitivity at low masses. We also study how the sensitivity changes when the relative coupling strengths to the electroweak gauge fields are varied, showing that the three-photon channel can provide information complementary to photon-fusion probes of ALPs.

    hep-phhep-ex0 citations
17. 17*

    Gravitational Waves from Black Hole Reheating: The Scalar-Induced Component

    Yann Gouttenoire🇩🇪 · Nicholas Leister🇩🇪 · Pedro Schwaller🇩🇪

    The reheating of the universe by the evaporation of light primordial black holes (PBHs) can leave a stochastic gravitational-wave (GW) background in the early Universe. In the monochromatic limit, their simultaneous evaporation produces an abrupt matter-to-radiation transition, triggering the so-called Poltergeist GW signal, usually predicted to be dominant and observable. We revisit this result by including the irreducible mass spread implied by gravitational collapse in General Relativity, whose infrared tail scales as $d{f}_{\mathrm{PBH}}/d\ln M_{\mathrm{PBH}}\propto M_{\mathrm{PBH}}^{3.78}$. We show that this minimal width smooths reheating enough to suppress the Poltergeist background by orders of magnitude, down to the level of the scalar-induced GW signal produced during a generic early matter era, such as one driven by the decay of a heavy relic. We provide a complete decomposition of the scalar-induced spectrum into eight production channels and find that none, except the one from PBH formation, reaches either the $\Delta N_{\mathrm{eff}}$ bound or the projected sensitivity of future GW observatories. This reopens regions of ultra-light PBH parameter space previously thought to be excluded by these constraints.

    hep-phastro-ph.COgr-qc1 citation
18. 18*

    Opening the Window of Ultra-Light PBHs by Exorcising the Poltergeist

    Yann Gouttenoire🇩🇪 · Nicholas Leister🇩🇪 · Pedro Schwaller🇩🇪

    The hot Big Bang may have emerged from evaporation of primordial black holes (PBHs) lighter than $10^9$g. Standard monochromatic treatments predict nearly simultaneous evaporation, abrupt reheating, and a large Poltergeist scalar-induced gravitational wave signal. We confront this expectation with the irreducible collapse mass tail predicted by general relativity, $d{f}_{\mathrm{PBH}}/d\ln M\propto M^{3.78}$, which smooths reheating, suppresses the signal by orders of magnitude, and reopens the ultra-light PBH window.

    hep-phastro-ph.COgr-qc1 citation
19. 19*

    The Mass Gap Approach to QCD. II. The non-perturbative renormalization theory for the massive gluon fields

    V. Gogokhia🇭🇺 · G.G. Barnafoldi🇭🇺

    The previously formulated the mass gap approach to QCD, based on a new insights into its ground state(vacuum), makes it possible to exactly define the dynamically generated gluon pole mass. We developed a non-perturbative multiplicative renormalization program for the corresponding massive full gluon propagator. Its asymptotic properties have been analyzed, including the perturbation theory limit to the free gluon state, i.e., no asymptotic freedom effect. The peculiarities of the mass-shell structure of the massive full gluon propagator has been discussed. The inconsistency of the canonical gauge in QCD is fixed. Our approach does not allow the massive gluons to be mass-shell objects. This prevents them to appear in the physical spectrum (confinement of the massive gluon states). The massive gluons may exist in the vacuum or inside hadrons only. Expression for massive full gluon propagator in Euclidean metric for the lattice simulations is present. It is also shown that the massive solution has a correct limit to the massless full gluon propagator, when the gluon pole mass is to be formally put zero.

    hep-phhep-th0 citations
20. 20*

    Echoes of Nucleon Decay from Long-Lived Particles

    Patrick Adolf🇩🇪 · Chandan Hati🇪🇸 · Martin Hirsch🇪🇸 · Volodymyr Takhistov🇯🇵

    Nucleon decay searches provide uniquely sensitive probes of baryon number violation and physics beyond the Standard Model. We propose a new class of nucleon decay observables involving long-lived particles (LLPs), characterized by spatially separated but temporally correlated "echo" vertices not captured by conventional prompt searches. Focusing on vector LLPs, we construct effective operators and ultraviolet realizations, and show that Super-Kamiokande, Hyper-Kamiokande and JUNO can achieve geometric acceptances approaching 80% over a broad range of LLP decay lengths. Echo signatures could in principle arise from any visibly decaying LLP.

    hep-phhep-ex2 citations
21. 21*

    Precision physics at the muon collider: $m_W$ and CKM matrix elements

    Ludovica Aperio Bella🇩🇪 · Roberto Franceschini🇮🇹 · Federico Meloni🇩🇪 · Xing Wang🇺🇸

    We examine the potential for a 10~TeV lepton collider to carry out precision measurements of the W boson mass and W boson couplings strength, i.e. the CKM matrix elements. We consider the several W boson production mechanisms and focus on the most copious at 10~TeV, that is effective $\gamma W\to W$, a process viable at both opposite sign and same-sign leptonic colliders. We find that the leptonic W decay channel can hardly be competitive with present determinations, due to lack of rate. The hadronic channel has potential to improve over the current $\simeq$10~MeV from measurements at hadron colliders, motivating detector developments towards high-precision hadronic energy measurements. We find that the precision understanding of the detector response to hadrons can also lead to a determination of the CKM matrix elements. We expect determination of CKM matrix elements surpassing by far the present precision for couplings involving heavy quarks, notably $V_{cb}$, avoiding the present bottle-necks due to poor knowledge of hadronic matrix elements needed in low energy extractions of CKM matrix elements. Our findings motivate detector developments towards high-precision hadronic energy measurements and flavor tagging.

    hep-phhep-ex0 citations
22. 22*

    Exploring the SMEFT landscape: Bayesian Model Selection for indirect discovery

    Luca Mantani🇪🇸

    We develop a framework for indirect discovery in the Standard Model Effective Field Theory (SMEFT) based on Bayesian model selection over operator subsets. We argue that SMEFT should be understood as a structured space of competing hypotheses rather than a single high-dimensional model, with each operator subset corresponding to a physically distinct low-energy realisation of new dynamics. Bayesian inference is applied at the level of model space itself, assigning posterior probabilities to operator subsets and marginal inclusion probabilities to individual operators. A genetic algorithm efficiently navigates the high-dimensional discrete model space, concentrating evaluations in the high-posterior region, while the Bayesian Information Criterion provides a tractable approximation to the Bayesian evidence. We apply this framework to a dataset comprising electroweak precision observables from LEP and Higgs, top-quark, and diboson measurements from LHC Run 2, at both linear and quadratic order in the Wilson coefficients, with one-loop renormalisation group evolution systematically included. The analysis finds no statistically significant evidence for any departure from the SM, and demonstrates that Bayesian Model Average posteriors on Wilson coefficients carry substantially improved characterisation potential compared to traditional global fits. The operator correlation matrix encodes the relational structure of the model posterior, identifying operator pairs that co-appear in high-posterior models and flat directions where additional measurements would be most valuable. The sensitivity of all results to the choice of matching scale ${\mu }_0$ is assessed, and its promotion to a continuous parameter of inference is identified as a natural extension of the framework.

    hep-phhep-ex1 citation
23. 23*

    Quantum Simulation of Gauge Theories for Particle and Nuclear Physics

    Zohreh Davoudi🇺🇸

    Lattice field theory, along with its algorithmic and hardware ecosystems, has been at the forefront of computational particle and nuclear physics. It continues to deliver impressive results on the hadronic spectrum, structure, decays, and reactions. Yet, this vigorous campaign has fallen short in addressing a range of problems involving dense matter and general dynamical phenomena. The reason is that such problems require an exponential scaling of computing time and space in system size. Quantum simulation, enabled by quantum-computing algorithms and hardware technology, promises a way forward by offering several polynomially efficient algorithms compared with their inefficient classical counterparts. Lattice gauge theorists have engaged in a multi-pronged program to leverage such new possibilities, and have steadily advanced the state of theory, algorithm, and hardware implementations and co-design. In this talk, I motivate the quantum-computational lattice-field-theory program; introduce the questions such a program is expected to address and the strategies it involves; report on recent progress; and end with a note on challenges and opportunities ahead.

    ↳ hep-lathep-phnucl-thquant-phPoS(2026)·4 citations
24. 24*

    The Causal Bootstrap: Bounding Smeared Spectral Functions from Non-Perturbative Euclidean Data

    Ryan Abbott🇺🇸 · Sarah Fields🇺🇸 · William I. Jay🇺🇸 · Patrick Oare🇺🇸 · Matteo Saccardi🇺🇸

    This work introduces the causal bootstrap, a framework for bounding smeared spectral observables from finite non-perturbative Euclidean data. The method optimizes over the convex set of positive spectral densities compatible with the data to compute rigorous upper and lower bounds on the target observable. Statistical uncertainties, including correlations, are incorporated through compatibility regions using the covariance matrix. The bounds are equivalent, via Lagrange duality, to certified bounds on the target smearing kernel. For polynomial, rational, and piecewise rational kernels, the resulting dual problems can be reduced to finite-dimensional semidefinite programs using techniques familiar, e.g., in the numerical conformal bootstrap. The present formulation clarifies the relation to moment problems, Nevanlinna--Pick interpolation, and linear kernel-reconstruction methods. Numerical examples demonstrate the method.

    ↳ hep-lathep-phhep-th8 citations
25. 25*

    Entangling Power: A Probe of Symmetry and Integrability in Quantum Many-Body Systems

    Ian Low🇺🇸 · Pallab Goswami🇺🇸

    The entangling power of a unitary operator quantifies its ability to generate entanglement from product states and provides a natural probe of quantum many-body dynamics. Entanglement extremization at points of enhanced symmetry has previously been observed in high-energy scattering. In this work we compute the time-averaged entangling power of anisotropic Heisenberg spin chains across two-site models and finite-size systems, as well as the entangling power of the two-magnon $S$-matrix in the thermodynamic limit. For two-site models we establish a monotonic hierarchy: the entangling power decreases as the symmetry group grows, reaching its minimum at the $SU(2)$ XXX point. Finite-size XXZ chains exhibit sharp dips at the $SU(2)$ points $\Delta =\pm 1$ and the free-fermion point $\Delta =0$, with the free-fermion dip decaying much more slowly with system size. In the thermodynamic limit, we decompose the two-magnon $S$-matrix into quantum logic gates -- Identity, SWAP, and ${\sigma }_z\otimes {\sigma }_z$ -- and show that the entangling power vanishes for all scattering energies at the $SU(2)$ points, where the $S$-matrix reduces to the Identity gate, while the free-fermion point achieves the maximum -- the opposite of the finite-size many-body behavior. The entangling power can serve as an {\em operator} diagnostic for symmetry and selected aspects of integrability in quantum simulations of spin-chain dynamics.

    ↳ quant-phcond-mat.str-elhep-phhep-th+14 citations
26. 26*

    Exact Holographic Kinematics in AdS/CFT

    Haitang Yang🇨🇳

    We propose that holography contains an exact kinematic sector distinct from holographic dynamics. The appropriate setting for this sector is a CFT on an open solid torus in the Weyl frame. The open solid torus introduces an intrinsic scale, and the Weyl frame makes this scale manifest as an extra bulk direction. The resulting bulk-boundary pairs are exact and finite: no cutoff, large-$N$ limit, strong-coupling assumption, or heavy-operator approximation is required. The AdS geometry appearing in this sector should be understood as a kinematic geometry; only in special CFTs and appropriate limits is it promoted to a dynamical semiclassical bulk. The standard boundary-anchored dictionary entries are recovered only as singular limits. As a striking demonstration, we show that Weyl-frame two-point functions provide a replica-free definition of entanglement entropy.

    ↳ hep-thgr-qchep-ph2 citations
27. 27*

    Contrastive self-supervised convolutional autoencoder for core-collapse supernova gravitational-wave detection

    Tian-Yang Sun🇨🇳 · Yue Niu🇨🇳 · Chun-Yan Jiang🇨🇳 · Shang-Jie Jin🇨🇳 · Yong Yuan🇨🇳 · Xin Zhang🇨🇳

    Gravitational-wave astronomy has opened a direct observational window onto compact-object dynamics, strong-field gravity, and cosmology. Among the transient sources accessible through this window, core-collapse supernovae (CCSNe) are uniquely valuable because their signals can probe the engine of stellar collapse, proto-neutron-star dynamics, and explosion asymmetries, yet their weak, stochastic, and model-dependent waveforms remain difficult to detect. In this work, we develop a contrastive self-supervised convolutional autoencoder (CS-CAE) for CCSNe gravitational-wave signal detection. The method combines a convolutional autoencoder (CAE), a noise-centered latent regularizer, and a projection head trained with a contrastive objective. This design encourages independent noisy realizations of the same CCSNe signal to be mapped to nearby latent representations, thereby reducing the influence of random noise fluctuations. CS-CAE achieves performance comparable to a supervised convolutional neural network while clearly outperforming a conventional CAE baseline, and generalizes better to unseen numerical CCSNe waveform families. Under the Einstein Telescope (ET) detector configuration, the method achieves an effective sensitive distance of approximately 120 kpc and shows improved separation of CCSNe signals from stationary noise and transient glitches in the low-false-alarm regime. These results highlight the potential of CS-CAE as a robust and less template-dependent framework for CCSNe gravitational-wave searches.

    ↳ gr-qcastro-ph.COastro-ph.IMhep-ph3 citations
28. 28*

    Causal UV completions of relativistic hydrodynamics

    Robbe Brants🇧🇪

    Relativistic hydrodynamics successfully provides an effective field theory description for the low energy regime of many out-of-equilibrium systems. On the other hand, in this paper we prove that any stand-alone hydrodynamic EFT is inherently acausal and therefore requires the addition of transient UV modes in order to restore causality. This is made possible by the exponential decay of dissipative hydrodynamics in a majority of the lightcone, allowing the possibility of a causal description that still reduces to the hydrodynamic one at late timescales. We then investigate the emergence and possible restrictions of the non-hydrodynamic modes in these causal UV completions.

    ↳ hep-thhep-phmath-phmath.MP+12 citations
29. 29*

    Chiral Electromagnetic Surface Waves on Chern-Simons Interfaces

    Nemanja Kaloper🇺🇸

    We show that Maxwell theory with a codimension-$1$ Chern-Simons interface supports chiral electromagnetic surface waves on the interface, even when the bulk theory on both sides is conventional vacuum electrodynamics in infinite space. Solving the exact boundary value problem we find that the Chern-Simons interaction acts with opposite sign on the two helicities oriented along the interface, giving rise to one normalizable mode localized on the interface. This mode is a gapless chiral surface photon with linear dispersion and a frequency-independent index of refraction set by the Chern-Simons coefficient. This mode exists despite the absence of ambient material response or geometric confinement.

    ↳ hep-thcond-mat.mes-hallhep-phphysics.optics+1PRD(2026)·1 citation
30. 30*

    Multipositivity Constrains the Chiral Lagrangian

    Clifford Cheung🇺🇸 · Jaehoon Jeong🇰🇷 · Pyungwon Ko🇰🇷 · Alex Pomarol🇪🇸 · Grant N. Remmen🇺🇸 · Francesco Sciotti🇪🇸

    The chiral Lagrangian is a cornerstone of modern particle physics, offering a systematic and quantitative description of low-energy pions. Using tools from the modern scattering amplitudes program, we show that consistent multiparticle dynamics impose novel constraints on the coupling constants of this theory. In the planar limit, these constraints imply that certain Wilson coefficients of the chiral Lagrangian are bounded from below by the chiral anomaly. Our results reveal a subtle connection between the anomalous and nonanomalous sectors of the underlying strong interactions, while introducing a novel formulation of multipositivity bounds that holds for any planar tree-level theory.

    ↳ hep-thhep-ph7 citations
31. 31*

    Expanding quantum magnetic field

    Bogdan Damski🇵🇱

    We develop the quantum theory of the causal formation of a long-range magnetic field generated by an external current that is instantaneously switched on and subsequently kept constant in time. The resulting non-equilibrium quantum state, describing the expanding magnetic field, is obtained exactly and compared with the corresponding quantum magnetostatic state. In contrast to the magnetostatic case, the expanding solution exhibits a propagating shockwave-like front separating regions where the magnetic field has already been formed from those that remain causally disconnected from the source. We show that although the expanding field locally approaches the magnetostatic field behind the shockwave-like front, the associated quantum systems remain distinct at all times. In particular, we obtain manifestly different results for the energy, photon number, and their fluctuations in expanding and magnetostatic field configurations. Our results are first derived for a general external current and then illustrated with a specific example.

    ↳ quant-phhep-phhep-th0 citations

* 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.