Thu·Jun 12, 2025Thursday·June 12, 2025

1. 01*

   Freezing-in Cannibals with Low-reheating Temperature

   Nicolás Bernal🇦🇪 · Esau Cervantes🇵🇱 · Kuldeep Deka🇦🇪 · Andrzej Hryczuk🇵🇱

   The freeze-in mechanism provides a compelling framework for dark matter (DM) production, particularly suited to scenarios involving feeble interactions with the Standard Model (SM). In this work, we highlight a possible interplay of a non-instantaneous reheating phase and dark sector self-interactions, specifically $2\to 3$ and $3\to 2$ cannibalization processes. As an example we study the freeze-in production of a complex scalar DM candidate stabilized by a ${\mathbb{Z}}_3$ symmetry permitting cubic self-couplings, enabling number-changing interactions that drive internal thermalization and significantly modify the dark sector number density and temperature evolution. We numerically solve the coupled Boltzmann equations for the DM number density and temperature alongside the evolving SM bath, accurately capturing the dynamics of a prolonged reheating epoch. Our analysis reveals a rich and distinctive phenomenology arising from the interplay between the Universe's thermal history, Higgs portal mediated production, and cannibalistic self-interactions. Compared to scenarios with instantaneous reheating or negligible self-interactions, our framework opens new viable regions in parameter space, particularly for light DM, potentially within reach of future probes.

   hep-phhep-thJHEP(2025)·12 citations
2. 02*

   Does the existence of $f_0$ meson enlarge the $K^{+}\to {\pi }^0{\pi }^0{\pi }^0{e}^{+}\nu$ decay probability?

   E. K. Karkaryan🇷🇺 · V. F. Obraztsov🇷🇺 · M. I. Vysotsky🇷🇺

   We estimate a possible contribution of the two-pion system $f_0(500)$ wide resonance to the decay probability of the super rare decay $K^{+}\to 3{\pi }^0{e}^{+}\nu$. We vary the width of the resonance from 0.01 MeV to 1000 MeV. We found that the contribution of the narrow resonance in a system of several final state particles into the decay probability is proportional to its width. However it never exceeds the value of the decay probability calculated on free final state particles neglecting the resonance contribution.

   hep-phhep-exJETP Lett.(2025)·0 citations
3. 03*

   Exotic multistrange-anticharm baryon systems

   Jing Song🇨🇳 · Eulogio Oset🇪🇸

   We study exotic baryon systems composed of anticharmed mesons and strange baryons using the extended local hidden gauge approach. By solving the coupled-channel Bethe-Salpeter equation with interaction kernels from vector meson exchange, we explore the formation of hadronic molecular states in sectors with strangeness $S=-1$, $-2$, $-3$ and $-4$. {We systematically consider all possible isospin configurations and include both octet and decuplet baryons in the coupled-channel systems.} \textcolor{black}{Our results indicate that attractive interactions in $S=-1,-2$ can dynamically generate bound states, while systems with $S=-3,-4$ have repulsive interactions and do not support molecular formation.} We also investigate vector-baryon systems with ${\bar{D}}^{\ast }$ and ${\bar{D}}_s^{\ast }$ mesons, finding similar but more deeply bound states. The results show that bound exotic states are more likely when one or two strange quarks are present. {To assess the robustness of our predictions, we perform an uncertainty analysis by varying the cutoff parameter \( q_{\text{max}} \), which affects the loop function regularization. The variations lead to moderate shifts in the pole positions, confirming the qualitative stability of the molecular states.} These results highlight the strangeness dependence of the molecular formation mechanism and provide theoretical predictions that can guide future experimental searches for exotic multistrange-anticharm baryon systems.

   hep-phPRD(2025)·3 citations
4. 04*

   Machine Learning Left-Right Breaking from Gravitational Waves

   William Searle🇦🇺 · Csaba Balázs🇦🇺 · Yang Xiao🇨🇳 · Yang Zhang🇨🇳

   First-order phase transitions in the early universe can generate stochastic gravitational waves (GWs), offering a unique probe of high-scale particle physics. The Left-Right Symmetric Model (LRSM), which restores parity symmetry at high energies and naturally incorporates the seesaw mechanism, allows for such transitions -- particularly during the spontaneous breaking of $SU(2{)}_R\times SU(2{)}_L\times U(1{)}_{B-L}\to SU(2{)}_L\times U(1{)}_Y$. This initial step, though less studied, is both theoretically motivated and potentially observable via GWs. In this work, we investigate the GW signatures associated with this first-step phase transition in the minimal LRSM. Due to the complexity and dimensionality of its parameter space, traditional scanning approaches are computationally intensive and inefficient. To overcome this challenge, we employ a Machine Learning Scan (MLS) strategy, integrated with the high-precision three-dimensional effective field theory framework -- using PhaseTracer as an interface to DRalgo -- to efficiently identify phenomenologically viable regions of the parameter space. Through successive MLS iterations, we identify a parameter region that yields GW signals detectable at forthcoming gravitational wave observatories, such as BBO and DECIGO. Additionally, we analyse the evolution of the MLS-recommended parameter space across iterations and perform a sensitivity analysis to identify the most influential parameters in the model. Our findings underscore both the observational prospects of gravitational waves from LRSM phase transitions and the efficacy of machine learning techniques in probing complex beyond the Standard-Model landscapes.

   hep-phJCAP(2025)·5 citations
5. 05*

   Searching for beyond-Standard-Model solar neutrino interactions using directional detectors

   Anirudh Chandra Shekar🇺🇸 · Chiara Lisotti🇦🇺 · Nityasa Mishra🇺🇸 · Ciaran A. J. O'Hare🇦🇺 · Louis E. Strigari🇺🇸

   Micro-pattern gaseous detectors (MPGDs) are a class of technologies that enable the full three-dimensional spatial reconstruction of ionisation tracks from nuclear and electron recoils in gas. Anticipating near-future 30 m${}^3$-scale time projection chambers with MPGD-based readout, we forecast the sensitivity of such directionally-sensitive low-energy recoil detectors to neutrino interactions beyond the Standard Model. We work in the framework of neutrino non-standard interactions (NSIs), and calculate the combined recoil energy-angle distributions of the electron recoil signal generated by solar neutrinos in atmospheric-pressure He:CF${}_4$ gas. We estimate the expected exclusion limits that such an experiment could place on various NSI parameters, as well as the mass and coupling of a new light mediator that interacts with electrons and neutrinos. We find that with an achievable background reduction of around a factor of ten from current estimates for a 30 m${}^3$ optical-readout detector using this gas mixture, sensitivity to NSI parameters would already approach Borexino's sensitivity. Directionality also allows for event-by-event neutrino energy reconstruction, which would provide a means to resolve some parameter degeneracies present in the modified neutrino cross section in this formalism. Our results strongly motivate the development of small-scale directionally-sensitive gas detectors for neutrino physics.

   hep-phhep-exPRD(2025)·5 citations
6. 06*

   Spin alignment of Quarkonia: A Possible Probe of Deconfined QCD matter in Pb+Pb Collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV

   Bhagyarathi Sahoo🇮🇳 · Captain R. Singh🇮🇳 · Raghunath Sahoo🇮🇳

   In this study, we investigate the influence of deconfined QCD matter on quarkonium spin alignment in ultra-relativistic heavy-ion collisions. We estimate the spin alignment of charmonium ($J/\psi$, and $\psi$(2S)) and bottomonium (${\rm Y}$(1S), and ${\rm Y}$(2S)) states for Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV as a function of transverse momentum by calculating the energy eigenvalues in a thermal rotating medium. We solve the Schrödinger equation with a medium-modified color-singlet potential, considering the coupling of spin with vorticity and magnetic field. Furthermore, we evaluate the effect of medium temperature, vorticity, magnetic field, and momentum-space anisotropy on the elements of the spin density matrix. Our findings reveal that vorticity increases the spin alignment, while the magnetic fields and anisotropy modify the observables in a state-dependent manner. These findings deepen our understanding of quarkonium spin alignment in an anisotropic magneto-vortical thermal medium, shedding light on spin transport phenomena in heavy-ion collisions.

   hep-phhep-exhep-thnucl-ex+1EPJC(2026)·8 citations
7. 07*

   Heavy Quark State Production via p-p and O-O Collisions

   Leonard S. Kisslinger🇺🇸 · Debasish Das🇮🇳

   Here we have considered $J/\Psi$ is a normal charmonium meson, while $\Psi (2S)$ is a mixed hybrid charmonium meson. Similarly ${\rm Y}(1S)$ and${\rm Y}(2S)$ are normal upsilon mesons, while ${\rm Y}(3S)$ is a mixed hybrid upsilon meson. We discuss the differential rapidity cross sections for $J/\Psi$, $\Psi (2S)$, ${\rm Y}(1S)$, ${\rm Y}(2S)$, ${\rm Y}(3S)$ production via p-p, and O-O collisions at proton-proton energy $\equiv \sqrt{s_{pp}}$= 5.44 TeV. The rapidity taken for the present study goes from y=-1 to 1.

   hep-phhep-exnucl-exnucl-th0 citations
8. 08*

   Evidence for BSM spin 0 and spin 2 resonances at LHC Possible Interpretations

   Alain Le Yaouanc🇫🇷 · François Richard🇫🇷

   Nine statistically significant decay channels are observed in LHC data around a mass of 650 GeV. We interpret three of them as coming from a 20 GeV wide resonance observed in e+e-, 2 photons and ZZ into four leptons which could be a J=2 Kaluza Klein graviton resonance called T700 (T for tensor with J=2). This hypothesis is reinforced by noting that this signal is produced by VBF and not by ggF since it disappears in ZZ when treated as a scalar. Given that the six other excesses have poor mass resolution, one cannot exclude the presence of an additional wide scalar resonance called H650. Assuming a Randall Sundrum RS model, we conclude that LHC observes the predicted sequence T380, T700 and T1000, with prospects to discover heavier states by reconstructing hadronic states. At variance with the RS model, T700 decouples from gluon and photon pairs, suggesting a composite model interpretation in which preons are charge neutral and colourless. T700 does significantly couple to $e^{+}{e}^{-}$ which has implications for future $e^{+}{e}^{-}$ colliders. Perturbative unitarity requirements predict $T^{++}\to W^{+}{W}^{+}$ and $T^{+}\to ZW$ resonances, again indicated by LHC data. With BR($e^{+}{e}^{-}$)~0.25%, measured by ATLAS and CMS, this scenario offers excellent prospects for abundantly (Gigafactory) producing a sequence of narrow resonances at future $e^{+}{e}^{-}$ colliders. For heavy scalars, the situation is less clear. Following ATLAS and CMS, we expect that the top loop contribution to the gluon-gluon fusion mechanism $ggF$ could produce a deficit rather than an excess in the mass distribution of top pairs, which prevents a standard estimate of the statistical significance for heavy resonances. It seems that the pseudo-scalar and scalar resonances A490 and H650, indicated by other channels, create observable deviations in the $t\bar{t}$ analyses presented by ATLAS and CMS.

   hep-phhep-ex6 citations
9. 09*

   Improving the description of dimuon production in neutrino-nucleus collisions using the SACOT-$\chi$ scheme

   Hannu Paukkunen🇫🇮 · Ilkka Helenius🇫🇮 · Sami Yrjänheikki🇫🇮

   Dimuon production in deeply inelastic scattering between neutrinos and nuclei plays an important role in constraining the strange-quark parton distribution functions (PDFs). Here, we present a self-contained calculation of this process consisting of a next-to-leading order semi-inclusive charmed-hadron production in the SACOT-$\chi$ general-mass variable-flavor-number scheme, followed by a semi-leptonic decay of the charmed hadron. We find that invoking the SACOT-$\chi$ scheme introduces modifications up to $20\%$ in comparison to our previous esimates, where only kinematic mass effects were considered through the slow-rescaling variable. We reiterate our earlier observation that the effective acceptance correction - typically used in global PDF fits as a simplifying approximation - depends on the perturbative order, PDFs, scales, and also on the treatment of heavy-quark effects. We find good agreement with the corresponding data from the NuTeV experiment.

   hep-phJHEP(2026)·4 citations
10. 10*

    Feynman Fox integrals in the physical region

    Giampiero Passarino (Turin U. and INFN, Turin)🇮🇹

    Feynman integrals in the physical region are transformed into Fox functions with a special emphasys to their cut structure

    hep-phhep-th1 citation
11. 11*

    Numerical computation of Fox functions

    Giampiero Passarino (Turin U. and INFN, Turin)🇮🇹

    In this work we discuss techniques for the numerical computation of Fox functions that represent Feynman integrals. Illustrative examples based on Sinc numerical methods and Quasi-Monte Carlo methods are given

    hep-phmath-phmath.MP1 citation
12. 12*

    Hard bremsstrahlung for the production of prompt photons

    A.A. Kampf (Lomonosov Moscow State University, Moscow, Russia, Dzhelepov Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, Dubna, Russia)🇷🇺

    The analytical calculation of helicity amplitudes for hard photon and gluon bremsstrahlung radiation are described using the spinor formalism for processes of the type $\bar{q}q\to g\gamma$ and $qg\to q\gamma$. The presented amplitudes are expressed in terms of field strength bivectors, with allowance for the dependence on the helicities and masses of all particles. Numerical calculations have been performed for the quark-antiquark annihilation process $\bar{c}c$ at the center-of-mass energies of 24, 91, and 500 GeV, considering various combinations of helicities of the quarks and the photon in the final state. This study is part of the ongoing development of theoretical support, based on the SANC system, for the analysis of polarized observables in proton collisions at the NICA collider.

    hep-phMoscow Univ.Phys.Bull.(2025)·0 citations
13. 13*

    Distinguishing Monochromatic Signals in LISA and Taiji: Ultralight Dark Matter versus Gravitational Waves

    Heng-Tao Xu🇨🇳 · Yue-Hui Yao🇨🇳 · Yong Tang🇨🇳 · Yue-Liang Wu🇨🇳

    Ultralight dark matter (ULDM) is an attractive candidate for cold dark matter, one of the main mysterious components of the Universe. Recent studies suggest that gravitational-wave (GW) laser interferometers can also detect bosonic ULDM fields, which would produce monochromatic signals resembling those from gravitational waves (GWs). Distinguishing between these potential origins therefore would be essential. In this work, we develop a method to address this challenge for space-based GW interferometers (such as LISA and Taiji) by utilizing the null-response channel (NRC) in interferometric combinations, a channel constructed to have zero response to a specific type of source from a given direction. We find that while the GW NRC remains blind to GWs from a specific direction, it still responds to ULDM, particularly at frequencies above the interferometer's critical frequency. The ULDM NRC exhibits similar behavior. Based on these observations, we outline a test procedure to discriminate between signal origins. Our method provides a new diagnostic tool for analyzing monochromatic signals in space-based GW interferometers, potentially expanding the scientific scope of future missions.

    hep-phastro-ph.COgr-qcPRD(2025)·8 citations
14. 14*

    Baryon-antibaryon generalized distribution amplitudes and $e^{+}{e}^{-}\to B\bar{B}\gamma$

    Jing Han🇨🇳 · Bernard Pire🇫🇷 · Qin-Tao Song🇨🇳

    Baryon-antibaryon generalized distribution amplitudes (GDAs) give an access to timelike gravitational form factors (GFFs) which are complementary to the spacelike ones which can be deduced from the hadronic generalized parton distributions (GPDs) measured in deep exclusive electroproduction processes. They allow to probe the GFFs of unstable baryons in the baryon octet, since the second moments of hadronic generalized distribution amplitudes (GDAs) lead to the timelike GFFs. These GDAs can be measured in the process $e^{+}{e}^{-}\to B\bar{B}\gamma$, in the generalized Bjorken regime where the invariant mass of the $B\bar{B}$ pair is near threshold at high energy facilities, such as BESIII, Belle II, and the proposed Super Tau-Charm Facility. In this work, we investigate this process using the QCD collinear factorization framework, where the scattering amplitudes are expressed in terms of the baryon timelike electromagnetic (EM) FFs and Compton FFs. We also provide a numerical estimate of the cross sections with a model for baryon-antibaryon GDAs. Our work provides us a possibility to extract the timelike baryon GFFs from near future experimental measurements, and these GFFs may be further used to study longstanding questions in hadronic physics such as the baryon spin decomposition and D-term.

    hep-phhep-exhep-thnucl-thPRD(2025)·4 citations
15. 15*

    Inclusive open charm photoproduction in ultraperipheral collisions at the LHC with G$\gamma$A-FONLL

    Matteo Cacciari🇫🇷 · Gian Michele Innocenti🇺🇸 · Anna M. Staśto🇺🇸

    We compute the inclusive $D^0$ production cross section in ultraperipheral Pb-Pb collisions at the LHC as a function of the $D^0$ transverse momentum and rapidity. These calculations are carried out within the new G$\gamma$A-FONLL (Generalized Photon-Nucleus FONLL) framework, which can predict photonuclear cross sections for charm and beauty hadrons in electron-proton, electron-nucleus, and ultraperipheral heavy-ion collisions. The framework relies on FONLL (Fixed-Order Next-to-Leading Logarithm) to model heavy-quark production in photonuclear collisions and employs a photon-flux reweighting procedure to describe the production cross sections in ultraperipheral heavy-ion collisions. The G$\gamma$A calculations are first validated against the photoproduction cross sections of $D^{\ast }$ in electron-proton collisions at HERA. The predictions for the $D^0$ production cross section in ultraperipheral Pb-Pb collisions at the LHC are then presented and compared to the first experimental results obtained by CMS at $\sqrt{{\mathrm{s}}_{\mathrm{NN}}}=5.36$ TeV. The predictions are benchmarked against different choices of nuclear parton distribution functions, fragmentation functions, and renormalization and factorization scales.

    hep-phPRD(2025)·11 citations
16. 16*

    Universality of scaling entropy in charged hadron multiplicity distributions at the LHC

    L. S. Moriggi🇧🇷 · F. S. Navarra🇧🇷 · M. V. T. Machado🇧🇷

    In this work, we investigate the scaling behavior of the entropy associated with the charged hadron multiplicity distribution P(N) in proton-proton collisions at the LHC. We show that the growth of this entropic indicator as a function of the Bjorken x variable exhibits a universal behavior, consistent with observations from deep inelastic scattering (DIS). This universality suggests that the entropy scaling is a property of the initial state and reflects the diffusive nature of gluon dynamics at small x. Furthermore, we demonstrate that high-multiplicity events are not accurately described by traditional KNO scaling and require a more precise description based on a diffusion scaling framework. This new scaling emerges naturally from the universal growth of partonic entropy and offers a deeper insight into the dynamics of particle production in high-energy hadronic collisions.

    hep-phhep-exhep-thPRD(2025)·7 citations
17. 17*

    The LHC as an Axion-Photon Collider

    Sergio Barbosa🇧🇷 · Matheus Coelho🇧🇷 · Sylvain Fichet🇧🇷 · Gustavo Gil da Silveira🇧🇷 · Magno Machado🇧🇷

    Assuming the existence of an axion-like particle (ALP), beams of relativistic particles emit fluxes of quasi-real ALPs, analogous to the photon fluxes described by Weizsäcker-Williams-type approximations. Consequently, ALP-ALP and ALP-photon collisions can occur at the LHC. We initiate the study of the LHC as an ALP collider, and show that ALP collisions provide competitive probes of certain ALP couplings. We show that ALP fluxes from heavy ions are suppressed relative to those from protons, unlike their photon counterpart. As a result, the most likely processes are ALP-photon collisions occurring in the proton-ion ($p$A) ultraperipheral collisions. Using our implementation of ALP fluxes in simulation tools, we show that ALP-photon collisions in $p$Pb efficiently probe ALP couplings to third generation fermions. LHC data with realistic $p$Pb luminosity can constrain the product of ALP couplings to nucleons and top quarks at the level of $O(0.01$ TeV${}^{-1})$. Notably, ALP-photon collisions naturally provide the leading probe of ALP flavor-violating couplings to the top quark. We suggest that the 2016 $p$Pb dataset collected at CMS, ATLAS, and LHCb should be explored for evidence of such collisions.

    hep-phPRL(2025)·6 citations
18. 18*

    Light Dark Matter Detection with Sub-eV Transition-Edge Sensors

    Muping Chen🇺🇸 · Volodymyr Takhistov🇯🇵 · Kazunori Nakayama🇯🇵 · Kaori Hattori🇯🇵

    We present a comprehensive analysis of high-resolution transition-edge sensors (TESs) as a quantum sensing platform for detecting dark matter (DM). Operating near the thermodynamic noise limit with sub-eV energy resolution, TESs offer a powerful approach for probing light DM in the sub-GeV mass range. Optical TESs, realized on superconducting films with critical temperatures below 150 mK, achieve energy thresholds below 100 meV and enable precise calorimetric detection of individual energy depositions. We model TES response by incorporating fundamental noise sources and applying optimal filtering techniques, and evaluate their sensitivity across a range of DM interaction channels, accounting for in-medium effects in the target material. We show that even ng-month-scale exposures can reach previously unexplored DM-electron scattering cross sections below $10^{-27}$ cm${}^2$ for sub-MeV masses, and can probe the MeV-scale mass range for DM-nucleon couplings. Combining high energy resolution, photon-number sensitivity, and scalability, optical TESs provide a compelling quantum sensing platform for rare-event searches at the intersection of particle physics and quantum metrology.

    hep-phhep-exphysics.ins-detquant-phPRD(2026)·8 citations
19. 19*

    Topological defects as effective dynamical dark energy

    Haipeng An🇨🇳 · Chengcheng Han🇨🇳 · Borui Zhang🇨🇳

    In this work, we consider the possibility that the dynamical dark energy hinted at by recent DESI data may be mimicked by the effects of additional components in the universe, potentially arising from topological defects. We find that the data does not show a particular preference for the existence of cosmic strings. However, a domain wall contribution at the percent level can improve the fit, yielding a $\Delta {\chi }^2=-1.72$ compared to the $\Lambda \mathrm{CDM}$ model. The improvement indicates that topological defects remain a viable and interesting extension to $\Lambda \mathrm{CDM}$, meriting further investigation with future cosmological data.

    hep-phastro-ph.COPRD(2026)·13 citations
20. 20*

    Electromagnetic signatures from pulsar remnants of binary neutron star mergers: prospects for unique identification using multi-wavelength signatures

    Mainak Mukhopadhyay🇺🇸 · Shigeo S. Kimura🇯🇵

    Binary neutron star (BNS) mergers can result in the formation of long-lived magnetar remnants which can enhance neutrino and electromagnetic (EM) emissions. In this work, we study the resulting multi-wavelength EM emissions and the prospects of their detectability in the current and upcoming EM telescopes. We model the pulsar-wind neubla system where the long-lived pulsar with dipolar magnetic fields of $10^{13}-10^{15}$ G (magnetar) spins down and is surrounded by an outward expanding nebula and kilonova ejecta. Although at early times post the merger, the EM signatures are unobservable due to heavy attenuation, they become observable on timescales of $\mathcal{O}(1-10)$ days after the merger. We find that the survey and follow-up observations have horizon distances $\gtrsim 1\mathrm{Gpc}$ for most of the wavebands and conclude that the detection prospects for such long-lived remnants in the electromagnetic channel are promising. This is of crucial importance for multi-messenger observations from BNS mergers to constrain the physical parameters of the remnants. Furthermore, we highlight how observations across the electromagnetic band can uniquely identify magnetar-powered transients resulting from BNS mergers and establish concrete associations of the detected gravitational wave signatures with such transients.

    ↳ astro-ph.HEhep-phApJL(2025)·9 citations
21. 21*

    Optimal Transport for $e/{\pi }^0$ Particle Classification in LArTPC Neutrino Experiments

    David Caratelli · Nathaniel Craig🇺🇸 · Chuyue Fang · Jessica N. Howard🇺🇸

    The efficient classification of electromagnetic activity from ${\pi }^0$ and electrons remains an open problem in the reconstruction of neutrino interactions in Liquid Argon Time Projection Chamber (LArTPC) detectors. We address this problem using the mathematical framework of Optimal Transport (OT), which has been successfully employed for event classification in other HEP contexts and is ideally suited to the high-resolution calorimetry of LArTPCs. Using a publicly available simulated dataset from the MicroBooNE collaboration, we show that OT methods achieve state-of-the-art reconstruction performance in $e/{\pi }^0$ classification. The success of this first application indicates the broader promise of OT methods for LArTPC-based neutrino experiments.

    ↳ hep-exhep-phphysics.ins-detPRD(2026)·0 citations
22. 22*

    $\eta$ and ${\eta }^{\prime }$ meson production in $J/\psi$ radiative decays from lattice QCD

    Mischa Batelaan🇺🇸 · Jozef J. Dudek🇺🇸 · Robert G. Edwards🇺🇸

    We report on the computation of amplitudes describing the radiative decay processes $J/\psi \to \gamma \eta$ and $J/\psi \to \gamma {\eta }^{\prime }$ from first principles via lattice QCD. Using lattices with two degenerate flavors of light quark and a heavier strange quark where $m_{\pi }\sim 391$ MeV, we compute three-point correlation functions using optimized meson operators with a range of momenta. The use of optimized operators allows access to the ${\eta }^{\prime }$, even though it appears as an excited state, lying above the ground-state $\eta$ in the isoscalar pseudoscalar channel. Statistically precise signals are obtained in this disconnected process by averaging over large numbers of kinematically equivalent correlators. We determine transition form-factors as a function of photon virtuality across the timelike region, which describe also the 'Dalitz' processes $J/\psi \to e^{+}{e}^{-}{\eta }^{(\prime )}$. Significantly lower magnitudes of transition form-factor for both the $\eta$ and ${\eta }^{\prime }$ are found than those extracted from experimental data, and possible explanations for this observation are presented.

    ↳ hep-lathep-phPRD(2025)·5 citations
23. 23*

    $\eta$ and ${\eta }^{\prime }$ production in $J/\psi$ radiative decays from quantum chromodynamics

    Mischa Batelaan🇺🇸 · Jozef J. Dudek🇺🇸 · Robert G. Edwards🇺🇸

    We present a first principles calculation within quantum chromodynamics (QCD) of the radiative decays of the $J/\psi$ into the light pseudoscalar mesons $\eta$ and ${\eta }^{\prime }$. Within a lattice computation we obtain the transition form-factors as a function of photon virtuality from the timelike region, accessible experimentally via the 'Dalitz' decay $J/\psi \to e^{+}{e}^{-}{\eta }^{(\prime )}$, through to the real photon point corresponding to $J/\psi \to \gamma {\eta }^{(\prime )}$. This is the first calculation in lattice QCD with two (heavier than physical) degenerate flavors of light quark and a heavier strange quark, in which the ${\eta }^{\prime }$ appears as the first-excited state with pseudoscalar isoscalar quantum numbers. We access it reliably by using variationally optimized operators, use of which also improves the purity of the $J/\psi$ and $\eta$ signals, reducing systematic uncertainties. High quality results at a large number of kinematic points are obtained in a typically noisy disconnected process by using a novel correlator averaging procedure. Our results show the expected enhanced production of the ${\eta }^{\prime }$ over the $\eta$ in this process, and suggest that the demonstrated lattice technology is suitable for future calculations considering processes in which light meson resonances are produced.

    ↳ hep-lathep-phPRL(2025)·7 citations
24. 24*

    Holography for QCD(Adj) and QCD(Adj)+F

    Anja Alfano🇬🇧 · Nick Evans🇬🇧 · Wanxiang Fan🇬🇧

    We discuss confinement and chiral symmetry breaking in SU(Nc) gauge theories with fermions in the adjoint representation. There has been considerable work on studying these theories compactified on a small circle (with compactification scale 1/L large relative to the strong coupling scale of the theory). The weakly coupled IR theory of photons exhibits confinement through a density of magnetically charged instanton configurations. As the compactification scale 1/L approaches the strong coupling scale, the IR theory becomes strongly coupled. In this regime we propose a holographic description of the IR degrees of freedom. The instanton condensation scale can be associated with a scale at which the Brietenlohner-Freedman (BF) bound is violated in the model and the glueball spectrum computed. We can also introduce the adjoint fermions which holographically display a BF bound violation associated to their running anomalous dimension. Very naively extending the perturbative results to the non-perturbative regime suggests that chiral symmetry breaking might occur ahead of confinement, but equally they may be joined phenomena. If the two phenomena are separate, then it would be useful to be able to enlarge the gap in scales. We propose adding fermions in the fundamental representation as well, which in a holographic model (that favours this separation) can greatly enlarge the gap to an order of magnitude. These results challenge the lattice community to seek such scale gaps (or their absence) to further understand the confining and chiral symmetry breaking dynamics.

    ↳ hep-thhep-lathep-ph4 citations
25. 25*

    QuGrav: Bringing gravitational waves to light with Qumodes

    Dmitri E. Kharzeev🇺🇸 · Azadeh Maleknejad🇬🇧 · Saba Shalamberidze🇺🇸

    We propose using qumodes, quantum bosonic modes, for detecting high-frequency gravitational waves via the inverse Gertsenshtein effect, where a gravitational wave resonantly converts into a single photon in a magnetized cavity. For an occupation number $n$ of the photon field in a qumode, the conversion probability is enhanced by a factor of $n+1$ due to Bose-Einstein statistics. Unlocking this increased sensitivity entails the ability to continuously prepare the qumode and perform non-demolition measurement on the qumode-qubit system within the qumode coherence time. Our results indicate that, at microwave frequencies and with existing technology, the proposed setup can attain sensitivities within 1.7 orders of magnitude of the cosmological bound. With anticipated near-future improvements, it has the potential to surpass this limit and pave the way for the first exploration of high-frequency cosmological gravitational wave backgrounds. At optical frequencies, it can enhance the sensitivity of current detectors by one order of magnitude. That further enhances their potential in reaching the single-graviton level.

    ↳ gr-qcastro-ph.IMhep-exhep-ph+1PRResearch(2026)·13 citations
26. 26*

    A new approach to quark mass determination using the gradient flow

    Hiromasa Takaura🇯🇵 · Robert V. Harlander🇩🇪 · Fabian Lange🇨🇭

    We propose a new method to determine quark masses using ratios of the vacuum-expectation values (VEVs) of flowed quark bilinear operators. They can be expressed as functions of the flow time $t$ and the $\overline{\mathrm{MS}}$ quark mass $\overline{m}$, which can then be determined by matching with the corresponding lattice results. Motivated by this, we evaluate these VEVs perturbatively through next-to-leading order in the strong coupling. We provide the results as expansions in the limits of small and large ${\overline{m}}^{2}t$. To this end, we develop a new expansion technique based on the Laplace transform. Additionally, we present numerical results with the exact mass dependence over a wide range of ${\overline{m}}^{2}t$. We discuss the expected perturbative precision for the mass determination based on our next-to-leading order perturbative calculations, and possible non-perturbative corrections.

    ↳ hep-lathep-phJHEP(2025)·3 citations
27. 27*

    Schwinger-Keldysh approach to tunneling transport at a hadron-quark interface

    Tingyu Zhang🇯🇵 · Hiroyuki Tajima🇯🇵 · Motoi Tachibana🇯🇵

    We theoretically discuss quantum tunneling transport and frictions at a hadron-quark matter interface based on the Schwinger-Keldysh approach combined with the tunneling Hamiltonian, which has been developed in the context of condensed matter physics. In the inner core of massive neutron stars, it is expected that cold quark matter appears at sufficiently high densities and hence exhibits color superconductivity, surrounded by nucleon superfluids at lower densities. The perturbative expressions of the tunneling current and the friction at the interface are obtained in terms of the non-equilibrium Green's functions. We demonstrate the DC Josephson current that occurs at the hadron-quark superfluid interface in the present scheme. Our framework can be applied to various conflagrations involving the interfaces relevant to astrophysical phenomena.

    ↳ nucl-thastro-ph.HEcond-mat.supr-conhep-ph+1PRD(2025)·2 citations
28. 28*

    Revisiting the phenomenologically emergent dark energy model: is non-zero equation of state of dark matter favored by DESI DR2?

    Tian-Nuo Li · Yi-Min Zhang · Yan-Hong Yao · Peng-Ju Wu · Jing-Fei Zhang · Xin Zhang

    The nature of dark matter remains one of the most fundamental and unresolved questions in modern cosmology. In most cosmological models, dark matter is typically modeled as pressureless dust with an equation of state (EoS) parameter $w_{\mathrm{dm}}=0$. However, there is no fundamental theoretical reason to exclude the possibility of a non-zero dark matter EoS parameter. In this work, we explore the possibility of a non-zero dark matter EoS within the phenomenologically emergent dark energy (PEDE) model, given its simplicity and proven ability to alleviate the Hubble tension. We perform observational constraints by using the latest baryon acoustic oscillation data from DESI DR2, the cosmic microwave background (CMB) data from Planck, and the type Ia supernova data from DESY5 and PantheonPlus. From our analysis, we observe that a negative dark matter EoS parameter is preferred in all scenarios. Specifically, the CMB+DESI+DESY5 data yields $w_{\mathrm{dm}}=-0.00093\pm 0.00032$, deviating from zero at approximately the $3\sigma$ level. However, this deviation is likely driven by unidentified systematics or inconsistencies in the DESY5 data, with the deviation decreasing to $2\sigma$ when using PantheonPlus data. Meanwhile, a negative $w_{\mathrm{dm}}$ would increase the Hubble tension due to the positive degeneracy between $w_{\mathrm{dm}}$ and $H_0$. Furthermore, Bayesian evidence suggests that the $\Lambda$CDM model is strongly preferred over the PEDE+$w_{\mathrm{dm}}$ model. These analyses illustrate that it is not possible to both support a non-cold dark matter component within the PEDE model and alleviate the Hubble tension simultaneously.

    ↳ astro-ph.COgr-qchep-phJCAP(2025)·52 citations
29. 29*

    An infrared bound on the ultraviolet bounce

    Mehrdad Mirbabayi🇮🇹 · Giovanni Villadoro🇮🇹

    Sometimes a local minimum is known to be a metastable vacuum inside the low-energy EFT, but the true vacuum lies outside, and the bounce solution mediating the decay cannot be found. For single-field decay, Espinosa has proposed a family of configurations called ``pseudo-bounces'' as a way to constrain the decay rate. They are parametrized by the central field value ${\Phi }_0$ and constructed without the knowledge of the true vacuum. We prove that the pseudo-bounce family has a monotonically decreasing decay exponent whose end point and minimum is the bounce action, and this continues to hold when gravitational effects are non-negligible. We then use this to estimate the decay rate (in the radion direction) of the promised AdS${}_3$ vacuum of the Standard Model.

    ↳ hep-thhep-phJHEP(2026)·0 citations
30. 30*

    Locating the QCD critical point with neutron-star observations

    Christian Ecker🇩🇪 · Niko Jokela🇫🇮 · Matti Järvinen🇰🇷

    We present a probabilistic model for the QCD critical endpoint (CEP) and the equation of state (EOS) at $\beta$-equilibrium, constrained by neutron-star observations. Using a hybrid framework that combines the holographic V-QCD model with an effective van der Waals description of nuclear matter, we generate a large ensemble of EOSs incorporating nuclear theory uncertainties. Constraining this ensemble with neutron-star mass-radius data and tidal deformability measurements from gravitational waves, we identify a strong first-order deconfinement transition at zero temperature, with a transition strength of $\Delta n_{\mathrm{PT}}/n_0=3.75_{-0.53}^{+0.70}$ and onset density $n_{\mathrm{PT}}/n_0=4.9_{-1.17}^{+1.33}$. The resulting posterior yields $95\%$ credible intervals for the CEP location: ${\mu }_{\mathrm{crit}}=626_{-179}^{+90}\mathrm{MeV}$, $T_{\mathrm{crit}}=119_{-6}^{+14}\mathrm{MeV}$.

    ↳ astro-ph.HEgr-qchep-phhep-th+1PRD(2026)·23 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.