Fri·Aug 29, 2025Friday·August 29, 2025

1. 01*

   Semi-inclusive pion electroproduction at the highest transverse momenta

   Andrei Afanasev🇺🇸 · Carl E. Carlson🇺🇸

   At the energies of present and future electron accelerators designed to study the structure of hadrons, there is a regime where hard pion electroproduction proceeds by a perturbatively calculable process in QCD. The process is not the leading twist fragmentation one but rather a higher twist process that produces kinematically isolated pions. Semi-inclusive data may teach us more about parton distribution functions of the target and the pion distribution amplitude. In addition, there is a connection to generalized parton distribution calculations of exclusive electroproduction of mesons in that the perturbative kernel is the same.

   hep-phPRD(2025)·0 citations
2. 02*

   Prospects for relic neutrino detection using nuclear spin experiments

   Yeray Garcia del Castillo🇦🇺 · Giovanni Pierobon🇦🇺 · Dipan Sengupta🇦🇺 · Yvonne Y. Y. Wong🇦🇺

   Direct detection of the cosmic neutrino background (C$\nu$B) remains one of the most formidable experimental challenges in modern physics. In this work, we extend recent studies of C$\nu$B-induced coherent transitions in polarised nuclear spin ensembles. Adopting an open quantum system framework, we model coherent neutrino effects in large spin ensembles using a Lindblad master equation that also incorporates realistic experimental imperfections such as local dephasing and imperfect polarisation. We solve the Lindblad equation numerically by way of a fast and computationally inexpensive method that can be extended to an arbitrarily large number of spins. Using our numerical solutions, we forecast the sensitivities of future experiments such as CASPEr to the local C$\nu$B overdensity parameter ${\delta }_{\nu }$. Our findings indicate that a CASPEr-like experiment, though primarily aimed at axion dark matter search, could also constrain the C$\nu$B overdensity to ${\delta }_{\nu }\sim 10^{13}$ in configurations achievable by currently planned experimental efforts, and down to ${\delta }_{\nu }\sim 10^{11}$ in the most optimised scenario. While C$\nu$B detection remains out of reach in the foreseeable future, our results highlight the potential of using quantum sensing to probe fundamental physics.

   hep-phPRD(2026)·7 citations
3. 03*

   Unitarity test of lepton mixing via energy dependence of neutrino oscillation

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

   We study the method to test the unitarity of the lepton mixing matrix by using only the long baseline neutrino oscillation experiments, such as the combination of the T2HK experiment and the one with the ${\nu }_e$ beam from a future neutrino factory at J-PARC. Without a specific parametrization, one can directly extract the elements of the lepton mixing matrix by observing the energy dependence of the oscillation probabilities. A non-trivial test of the unitarity under the three-generation assumption can thus be made possible by examining the orthogonality in a similar manner to the unitarity triangle in the quark sector. As the first trial, we perform the analysis based on the simplified situation where the matter effects in the neutrino oscillation can be neglected. Under this simplified analysis, we demonstrate the observation of the unitarity violation in the $3\times 3$ part of the lepton mixing matrix for a parameter set in the four-generation model. The statistically most significant measurement can be provided by the energy dependences of the combination of the CP conjugate modes, ${\nu }_{\mu }\to {\nu }_e$ and ${\bar{\nu }}_{\mu }\to {\bar{\nu }}_e$, at T2HK and, independently, by the T conjugate modes, ${\nu }_{\mu }\to {\nu }_e$ and ${\nu }_e\to {\nu }_{\mu }$, with the latter measured at the neutrino factory experiments.

   hep-phhep-exJHEP(2026)·1 citation
4. 04*

   Signals for fluctuating constituent numbers in small systems

   Andreas Kirchner🇺🇸 · Steffen A. Bass🇺🇸

   We propose an extension of the initial condition model TRENTo for sampling the number of partons inside the nucleons that participate in a heavy-ion collision. This sampling method is based on parton distribution functions (PDFs) and therefore has a natural dependence on the momentum transferred in the collision and the scale being probed during the collision. We examine the resulting distributions and their dependence on the momentum transfer. Additionally, we explore the sensitivity of different observables on the number of partons using the TRENTo framework and the estimators available therein for final-state observables.

   hep-phnucl-th1 citation
5. 05*

   Post-Reheating Inflaton Production as a Probe of Reheating Dynamics

   Kunio Kaneta🇯🇵 · Tomo Takahashi🇯🇵 · Natsumi Watanabe🇯🇵

   Cosmological reheating bridges the inflationary epoch and the hot big bang phase, yet its underlying dynamics remain poorly understood. In this work, we investigate a minimal scenario in which the inflaton evolves under a simple power-law potential during reheating and interacts with other particles via renormalizable couplings. We show that inflaton quanta can be regenerated from the thermal bath even after the decay of the coherent inflaton field, unveiling a previously overlooked channel for inflaton particle production, which offers a novel window into probing reheating. Remarkably, this mechanism may also account for the observed dark matter abundance, providing a natural link between early Universe dynamics and present-day cosmological observations.

   hep-phastro-ph.CO2 citations
6. 06*

   Superradiant Interactions for Relic Detection with Entangled Nuclear Spins

   Marios Galanis🇨🇦 · Onur Hosten🇦🇹 · Asimina Arvanitaki🇨🇦 · Savas Dimopoulos🇨🇦

   We recently showed that macroscopic nuclear spin ensembles prepared in coherent spin states can dramatically enhance the interaction rates of weakly interacting cosmic relics-such as dark matter and the cosmic neutrino background-through collective quantum effects analogous to Dicke superradiance, where the de-excitation and excitation rates scale as the square of the number of spins, $N^2$. We thus coined these processes superradiant interactions. In this paper, we propose a protocol to realize this enhancement and boost the discovery potential for such relics. We show how concepts from quantum optics can be adapted to nuclear spins coupled to superconducting circuits, enabling high-sensitivity systems. The spins are first initialized into a coherent spin state via a $\pi /2$ Rabi pulse from the ground state. When the circuit is sufficiently detuned from resonance, the spin-circuit interaction implements a squeezing Hamiltonian. Because squeezing must outpace spin relaxation and dephasing, the protocol favors macroscopic ensembles and high-quality superconducting circuits. During this squeezing phase, the standard quantum variance is reduced by up to 4.8 orders of magnitude-equivalent to 48 dB of squeezing-for circuits with quality factors $Q\sim 10^8$-$10^9$. The signal imprinted on the spins during the squeezing protocol can be magnified by further utilizing the squeezing interactions, easing the requirement for shot-noise-limited readout. This protocol has the potential to significantly accelerate axion and dark photon dark matter searches and extend the reach of existing axion experiments to probe QCD axion-nuclear spin couplings. More broadly, it paves the way for detecting coherent inelastic interactions from other cosmic relics-most notably the cosmic neutrino background-and establishes nuclear-spin-based systems as a new class of quantum, ultra-low-threshold detectors.

   hep-phquant-phPRA(2026)·6 citations
7. 07*

   Physics of the gluon mass gap

   Mauricio N. Ferreira🇨🇳 · Joannis Papavassiliou🇪🇸 · Jan M. Pawlowski🇩🇪 · Nicolas Wink🇩🇪

   It has long been known that the gluon propagator in Landau-gauge QCD exhibits a mass gap; and its emergence has been ascribed to the action of the Schwinger mechanism in the gauge sector of QCD. In the present work, we relate this property to the physical mass gap of QCD by considering two observables associated with confinement and chiral symmetry breaking, namely the confinement-deconfinement transition temperature and the pion decay constant, respectively. It turns out that the first observable is linearly proportional to the gluon mass gap, a fact that allows us to assign a direct physical meaning to this scale. Moreover, we identify three distinct momentum regimes in the gluon propagator, ultraviolet, intermediate, and deep infrared, and assess their impact on the aforementioned observables. Both observables are sensitive to the first two regions of momenta, where functional approaches essentially coincide, but are insensitive to the third, deep infrared, regime. The combined information is used for a simple fit for the gluon propagator, all of whose parameters admit a clear physical interpretation. Finally, we discuss how this fit can help us access the intertwined dynamics of confinement and chiral symmetry breaking in QCD-type theories.

   hep-phhep-lathep-thEPJC(2025)·11 citations
8. 08*

   Exploring Strangeness Enhancement and Particle Production in Small Collision Systems with EPOS4 at \sqrt{s_\rm{NN}} = 5.02 TeV

   Hirak Kumar Koley🇮🇳 · Subikash Choudhury🇮🇳 · Argha Deb🇮🇳 · Mitali Mondal🇮🇳

   The observation of collectivity and strangeness enhancement in small collision systems, such as proton-proton (pp) and proton-lead (p-Pb) collisions, challenges traditional assumptions regarding thermalization and particle production mechanisms. In this study, we investigate particle yields and transverse momentum distributions in pp and p-Pb collisions at \sqrt{s_\rm{NN}} = 5.02 TeV using the EPOS4 event generator, which employs a core-corona framework to model particle production across a variety of system sizes. EPOS4 successfully reproduces many qualitative trends observed in experimental data, including the hardening of $p_{\mathrm{T}}$-spectra with multiplicity, the hierarchical strangeness enhancement in strange-to-pion ratios, and characteristic modifications of particle yield ratios as a function of $p_{\mathrm{T}}$ and multiplicity. The microcanonical approach to core hadronization used in EPOS4 seems to provide a more realistic description of small systems compared to grand-canonical treatments. Nonetheless, quantitative discrepancies still persist in describing several physical observables. Future model refinements, including improved core-corona balancing, differential freeze-out conditions for multi-strange hadrons, and incorporation of finite strangeness correlation volumes, may be taken into account for enhancing EPOS4's predictive power and deepening our understanding of the complex dynamics governing the particle production in high-energy collisions.

   hep-phhep-exPRD(2025)·2 citations
9. 09*

   Electromagnetic properties of heavy-light mesons

   A. S. Miramontes🇪🇸 · J. Papavassiliou🇪🇸 · J. M. Pawlowski🇩🇪

   Within the Bethe-Salpeter framework, we present a computation of space-like electromagnetic form factors for pseudoscalar mesons, including light and heavy-light systems. Our approach employs a flavour-dependent variation of the standard Taylor effective charge, which contains key contributions from the quark-gluon vertices. This effective interaction is a common ingredient of all relevant dynamical equations, and accommodates the crucial mass differences between the various quark flavours. Particular attention is paid to the nonperturbative determination of the quark-photon vertex. The computed electromagnetic form factors for the pion and the kaon mesons show excellent agreement with experimental determinations. In addition, the predictions for the charge radii of heavy-light systems are in overall good agreement with lattice QCD.

   hep-phhep-latnucl-thEPJC(2025)·10 citations
10. 10*

    Threshold improved $ZH$ production at the LHC

    Goutam Das🇩🇪 · Chinmoy Dey🇮🇳 · M. C. Kumar🇮🇳 · Kajal Samanta🇬🇧

    We present precise theoretical results for the $ZH$ production cross section and invariant mass distribution at the Large Hadron Collider (LHC) taking into account the effects of soft gluons. We improve both quark-initiated and gluon-initiated subprocesses through threshold resummation within the QCD framework and present combined results relevant for $13.6$ TeV LHC.

    hep-phhep-exhep-thSciPost Phys.Comm.Rep.(2025)·1 citation
11. 11*

    Single- and double-heavy Hadronic Molecules

    C. Hanhart🇩🇪

    In this presentation the notion of hadronic molecules is reviewed and it is argued that some of the enigmatic single and double heavy mesons, namely the lowest lying positive parity open charm states, the $T_{cc}(3875{)}^{+}$ and the ${\chi }_{c1}(3872)$ aka $X(3872)$, that do not fit into the conventional quark--anti-quark scheme in fact qualify as hadronic molecules. For the single heavy states we show that an alternative explanation as diquark--anti-diquark structure is at odds with either phenomenology or lattice data. For the $X(3872)$ we discuss also the claimed isovector partner state, whose properties would provide additional strong support for a molecular structure of the $J^{PC}=1^{++}$ states near the $D{\bar{D}}^{\ast }$ thresholds. Its existence could be confirmed by, e.g., a high statistics measurement of the $J/\psi {\pi }^{+}{\pi }^{-}$ lineshape from $B^0\to K^{0}J/\psi {\pi }^{+}{\pi }^{-}$.

    hep-phhep-exhep-latPoS(2026)·0 citations
12. 12*

    The (3+1)D structure of the dilute Glasma

    Andreas Ipp🇦🇹 · Markus Leuthner🇦🇹 · David I. Müller🇦🇹 · Sören Schlichting🇩🇪 · Kayran Schmidt🇦🇹 · Pragya Singh🇫🇮

    We study the (3+1)D structure of the Glasma in the dilute approximation, which allows us to describe the longitudinal dynamics that arise from the three-dimensional nuclear structure. We employ a nuclear model with tunable longitudinal and transverse fluctuation scales that generalizes the McLerran-Venugopalan model. We discuss the longitudinal profiles of the energy-momentum tensor and the transverse structure of the local rest frame energy density.

    hep-phnucl-thEPJ Web Conf.(2026)·1 citation
13. 13*

    Updated Astrophysical Equation-of-State Constraints on the Color-Superconducting Gap

    Aleksi Kurkela🇳🇴 · Krishna Rajagopal🇺🇸 · Rachel Steinhorst🇺🇸

    We summarize and update using new NICER measurements the results of arXiv:2401.16253, in which we used various astrophysical neutron-star observations to set an upper bound on the CFL color-superconducting gap in a range of baryon chemical potentials ${\mu }_B\in [2.1,3.2]$, above those reached within neutron stars. We also corroborate the ``reasonable" constraint from arXiv:2401.16253 on the maximum value of the color-superconducting gap by performing a new Bayesian analysis using a prior that extends a two-segment Gaussian process connecting the whole density range between CEFT and pQCD.

    hep-phastro-ph.HEnucl-thEPJ Web Conf.(2026)·1 citation
14. 14*

    Progress in NLO Calculations for gamma-gamma Physics

    Hua-Sheng Shao🇫🇷 · Lukas Simon🇫🇷

    With the advent of precision measurements of photon-fusion processes in ultraperipheral collisions (UPCs) at facilities, such as RHIC and the LHC, the inclusion of higher-order corrections has become essential. While automated frameworks already make NLO corrections feasible for parton-parton scattering processes, no comparable tools had previously been available for UPC processes in two-photon collisions. In these proceedings, we review some recent explicit NLO computations and present the updated gamma-UPC+MadGraph5_aMC@NLO framework, the first automated software that enables NLO-accurate predictions for photon-photon processes in UPCs.

    hep-ph1 citation
15. 15*

    Analytical two-loop amplitudes of $e^{+}{e}^{-}⟶\mathbf{J}/\mathbf{\psi }+{\mathbf{\eta }}_c$ at $B$ factories

    Xiang Chen🇨🇭 · Xin Guan🇺🇸 · Chuan-Qi He🇨🇳 · Yan-Qing Ma🇨🇳 · Jian Wang🇨🇳 · Da-Jiang Zhang🇨🇳

    In double charmonium production, a long-standing challenge is that the theoretical predictions are not consistent with the measurements at B factories. Within the NRQCD framework, the next-to-leading order (NLO) calculation has proved its power to cut down the discrepancy between theory and experiments. To further clarify this puzzle, we have performed the next-to-next-to-leading order (NNLO) calculation. The amplitude is obtained as an analytical asymptotic expansion in the ratio of the squared charm-quark mass over the squared center-of-mass energy, $m_c^2/s$. We investigate the origin of the leading logarithms by performing a region analysis, revealing the intricate factorization structure in this process. We provide numerical predictions on the total cross sections of $J/\psi +{\eta }_c$ production, which agree with the experimental results. Extension of our computation to ${\rm Y}+{\eta }_b$ production is also discussed.

    hep-phhep-thPRD(2026)·8 citations
16. 16*

    Impact of new results from the ultraperipheral collision on modeling the proton and neutron emission in photon-induced nuclear processes

    P. Jucha🇵🇱 · K. Mazurek🇵🇱 · A. Szczurek🇵🇱 · K. Pysz🇵🇱

    The ultrarelativistic collisions of heavy ions provide rich spectrum of possibilities to discuss the response of the nucleus to photons. Newly published neutron and proton multiplicities measured in the ALICE experiment in ultraperipheral collisions allow investigating the influence of the electromagnetic fields on colliding nuclei for the ${}^{208}$Pb+${}^{208}$Pb at $\sqrt{s_{NN}}$=5.02~TeV. The theoretical predictions are done within hybrid model including equivalent photon approximations (EPA), GiBUU modeling of pre-equilibrium processes and generation of the exited nuclear remnants, which decay is modeled by statistical approach: GEM2 or GEMINI++. The cross-sections of the mass-charge distributions of nuclear remnants as well as the neutron, proton and other charged particle multiplicities are estimated. We concentrate on production of protons and isotopes coming from the electromagnetic dissociation. Special attention is devoted to emission of a single proton. The cross section for $1p$ emission is very close to maximal available one based on reactions of photon with individual nucleons. Our pre-equilibrium processes explain simultaneously the tail of neutron energy distributions in the nuclear rest frame observed in $\gamma +A$ collisions.

    hep-phnucl-thPRC(2026)·0 citations
17. 17*

    Probing Scalar-Mediator Quark Couplings via CLFV Lepton-Nucleon Scattering

    Yuichiro Kiyo🇯🇵 · Michihisa Takeuchi🇨🇳 · Yuichi Uesaka · Masato Yamanaka🇯🇵

    We investigate charged lepton flavor violating (CLFV) deep-inelastic scattering, focusing on the gluon-initiated subprocess ${\ell }_{i}g\to {\ell }_{j}g$ via the gluon effective operator $\varphi G_{\mu \nu }^a{G}_a^{\mu \nu }$, and demonstrate how to probe the nature of the CLFV mediator $\varphi$, specifically its mass and interaction with quarks. We consider two benchmark scenarios for the mediator-quark coupling: (i) $h$-like scenario, in which the mediator couples to heavy quarks in proportion to their masses, and (i\hspace{-1pt}i) $b$-only scenario, where the coupling is restricted to bottom quark only. We demonstrate that these scenarios can be discriminated by examining the dependence of the differential cross section on the momentum transfer. Furthermore, we show that the peak position of the differential cross section exhibits a pronounced sensitivity to both the mass of the mediator and the coupling strengths with quarks.

    hep-phhep-exPLB(2025)·0 citations
18. 18*

    Deep learning for jet modification in the presence of the QGP background

    Ran Li🇨🇳 · Yi-Lun Du🇨🇳 · Shanshan Cao🇨🇳

    Jet interactions with the color-deconfined QCD medium in relativistic heavy-ion collisions are conventionally assessed by measuring the modification of the distributions of jet observables with respect to their baselines in proton-proton collisions. Deep learning methods enable per-jet evaluation of these modifications, enhancing the use of jets as precision probes of the nuclear medium. In this work, we predict the jet-by-jet fractional energy loss $\chi$ for jets evolving through a quark-gluon plasma (QGP) medium using a Linear Boltzmann Transport (LBT) model. To approximate realistic experimental conditions, we embed medium-modified jets in a thermal background and apply Constituent Subtraction for background removal. Two network architectures are studied: convolutional neural networks (CNNs) using jet images, and dynamic graph convolutional neural networks (DGCNNs) using particle clouds. We find that CNNs achieve accurate predictions for background-free jets but degrade in the presence of the QGP background and remain below the background-free baseline even after background subtraction. In contrast, DGCNNs applied to background-subtracted particle clouds maintain high accuracy across the entire $\chi$ range, demonstrating the advantage of point-cloud-based graph neural networks that exploit full jet structure under realistic conditions.

    hep-phhep-exnucl-exnucl-thPRC(2026)·3 citations
19. 19*

    Vectorlike lepton imprints at lepton $g-2$ measurements and $e^{+}{e}^{-}$ colliders

    Sang Quang Dinh🇻🇳 · Hieu Minh Tran🇻🇳

    A fermion can be chiral or vectorlike with respect to a given symmetry, depending on its coupling to the corresponding gauge boson. Vectorlike fermions have a distinct property that their left-handed and right-handed components behave in the same way under the gauge symmetry. In this paper, we investigate an extension of the standard model with an $SU(2)$ doublet of vectorlike leptons and two complex scalars. The new physics effects on the lepton anomalous magnetic moment, as well as the electron and muon pair production processes at $e^{+}{e}^{-}$ colliders are analyzed. Taking into account the updated measurement results of the electron and muon $g-2$, the LEP and the LHC data, the viable parameter space of the model is identified. We also examine the prospect of testing the model using ${\mu }^{+}{\mu }^{-}$ signals from electron-position annihilation at the Future Circular Collider (FCC-ee). The analysis shows that the FCC-ee will be able to exclude a significant part of the parameter space, pinpointing exiguous viable regions to be tested in the future due to its high precision.

    hep-phhep-thPRD(2026)·0 citations
20. 20*

    Novel probes for electron-muon flavor violation from exotic Higgs decays

    P. Uttayarat🇹🇭 · J. Julio🇮🇩 · R. Primulando🇮🇩

    In this paper, we propose two novel signatures of Higgs decays to search for electron-muon flavor violation. These signatures arise from the presence of a light pseudoscalar into which the 125-GeV Higgs boson decays. The pseudoscalar subsequently decays into an electron-muon pair, leading to multilepton final states, which are relatively clean signatures to search for at the LHC. As a benchmark, we consider the type-III Two-Higgs-doublet-model. We analyze both low-energy and collider constraints on the model and identify regions of parameter space where the light pseudoscalar is viable. Our proposed signatures yield stronger constraints on the lepton flavor violating couplings than current low-energy precision measurements. Taken together, our findings suggest that collider-based probes of exotic Higgs decays provide a powerful complement to precision experiments in the quest to uncover new physics.

    hep-phJHEP(2026)·1 citation
21. 21*

    Cosmic-ray boosted inelastic dark matter from neutrino-emitting active galactic nuclei

    R. Andrew Gustafson🇺🇸 · Gonzalo Herrera🇺🇸 · Mainak Mukhopadhyay🇺🇸 · Kohta Murase🇺🇸 · Ian M. Shoemaker🇺🇸

    Cosmic rays may scatter off dark matter particles in active galactic nuclei, where both the densities of cosmic rays and dark matter are expected to be very large. These scatterings could yield a flux of boosted dark matter particles directly detectable on Earth, which enhances the sensitivity of dark matter direct detection and neutrino experiments to light and inelastic dark matter models. Here we calculate the cosmic-ray boosted dark matter flux from the neutrino-emitting active galactic nuclei, NGC 1068 and TXS 0506+056, by considering realistic cosmic-ray distributions, deep inelastic scatterings, and mass splittings in the dark sector. From this we derive novel bounds from these sources on light and/or inelastic dark matter models with Super-K and XENONnT. We find that cosmic-ray boosted dark matter from neutrino-emitting active galactic nuclei can test regions of parameter space favored to reproduce the observed relic abundance of dark matter in the Universe, and that are otherwise experimentally inaccessible.

    hep-phastro-ph.HEJCAP(2026)·16 citations
22. 22*

    Chemical and Kinetic Equilibrium in Cosmology: Facts and Myths

    Stefano Profumo🇺🇸

    We clarify that chemical and kinetic equilibration in the early Universe are distinct: neither implies the other, and the ordering of their decouplings need not be universal. We illustrate this with Standard-Model neutrino decoupling, strong-washout leptogenesis, dark-matter scenarios where kinetic decoupling precedes chemical freeze-out (resonant/forbidden, conversion/coannihilation, coscattering), and dark sectors at with temperatures distinct from the visible-sector temperature, with semi-annihilation or 3 $\to$ 2 cannibal dynamics. The moral of the story is simple: Chemical equilibrium governs numbers, kinetic equilibrium governs shapes. In an expanding Universe the operators that control them rarely fade at the same time, and when they do not, the order of decoupling is model dependent. Turning to phase-space evolution whenever momentum selectivity matters is the surest way to obtain robust cosmological predictions.

    hep-phastro-ph.COastro-ph.HEPRD(2025)·7 citations
23. 23*

    Baryogenesis via Asymmetric Evaporation of Primordial Black Holes

    Joaquim Iguaz Juan🇺🇸 · Yuber F. Perez-Gonzalez🇪🇸 · Jessica Turner🇬🇧

    We revisit baryogenesis from the asymmetric evaporation of light primordial black holes, focusing on scenarios where gravitational effects induce a matter antimatter asymmetry. In particular, we consider a higher-dimension operator coupling the Kretschmann scalar to a baryon-number-violating current which generates an effective chemical potential at the black hole horizon and leads to asymmetric Hawking radiation. Relative to earlier studies, we account for entropy dilution from evaporation, incorporate chemical potential dependent greybody factors and numerically track the fully coupled evolution of a PBH population in an expanding universe. We show that the observed baryon asymmetry can be reproduced within a viable region of parameter space for several PBH mass spectra including log-normal, critical-collapse, and power-law distributions.

    hep-phastro-ph.COJCAP(2026)·6 citations
24. 24*

    Dark-Matter-Enhanced Probe of Relic Neutrino Clustering

    Writasree Maitra🇺🇸 · Anna M. Suliga🇺🇸 · Vedran Brdar🇺🇸 · P. S. Bhupal Dev🇺🇸

    We propose heavy decaying dark matter (DM) as a new probe of the cosmic neutrino background (C$\nu$B). Heavy DM, with mass $\gtrsim 10^9$ GeV, decaying into neutrinos can be a new source of ultrahigh-energy (UHE) neutrinos. Including this contribution along with the measured astrophysical and predicted cosmogenic neutrino fluxes, we study the scattering of UHE neutrinos with the C$\nu$B via standard weak interactions mediated by the $Z$ boson. We solve the complete neutrino transport equation, taking into account both absorption and reinjection effects, to calculate the expected spectrum of UHE neutrino flux at future neutrino telescopes, such as the IceCube-Gen2 radio. We argue that such observations can be used to probe the C$\nu$B properties and, in particular, local C$\nu$B clustering. We find that, depending on the absolute neutrino mass and the DM mass and lifetime, a local C$\nu$B overdensity $\gtrsim 10^6$ can be probed at the IceCube-Gen2 radio within ten years of data taking.

    hep-phastro-ph.HEPRD(2026)·4 citations
25. 25*

    A Baryon and Lepton Number Violation Model Testable at the LHC

    Amit Bhoonah🇺🇸 · Francis Burk🇺🇸 · Da Liu🇺🇸 · Tong Ou🇺🇸 · Deepak Sathyan🇺🇸

    Proton decay experiments typically constrain baryon number violation to the scale of grand unified theories. From a phenomenological point of view, this makes direct probing of the associated new resonances, such as the X and Y bosons, out of reach for even the most optimistic future experiments. It has, however, been known that certain specific patterns of baryon and lepton number violation can suppress proton decay by multiple powers of the masses of the heavy resonances involved, opening the possibility that the observed limits on the proton lifetime are consistent with baryon number violating physics at energy scales much lower than that of grand unification. We construct an explicit example of such a model which violates baryon number by one unit, $\Delta \text{B}=-1$, and lepton number by three units, $\Delta \text{L}=-3$, and show that despite stringent limits on the predicted $p\to e^{+}/{\mu }^{+}\overline{\nu }\overline{\nu }$ mode from the Super-Kamiokande experiment, the masses of the newly introduced elementary particles can be $\mathcal{O}$(TeV). We identify interesting unique signatures of baryon number violation of this model that can be probed both with currently available LHC data and with the upcoming High-Luminosity LHC. We also present a scenario for low-scale baryogenesis within the framework of this model.

    hep-phhep-ex3 citations
26. 26*

    Revisiting extremely high energy QED bremsstrahlung in matter: large modifications to the LPM effect

    Peter Arnold🇺🇸 · Joshua Bautista🇺🇸 · Omar Elgedawy🇨🇳 · Shahin Iqbal🇵🇰

    Very high energy electrons initiate electromagnetic showers in ordinary matter that branch and multiply through bremsstrahlung and pair production. At extremely high energies, the quantum mechanical duration of these processes becomes longer than the mean free time to elastically scatter from the medium, which leads to a very significant suppression of bremsstrahlung (and pair production) known as the Landau-Pomeranchuk-Migdal (LPM) effect. We revisit the LPM effect for bremsstrahlung of energy $k_{\gamma }$ from an electron of energy $E$. We find that there are very large corrections to the LPM bremsstrahlung rate for certain regions of $(k_{\gamma },E)$ due to quantum overlap of bremsstrahlung and subsequent pair production. This possibility was first raised in the 1960s, when it was argued qualitatively that pair production would significantly decrease the bremsstrahlung rate in those regions of $(k_{\gamma },E)$ compared to the already-suppressed LPM bremsstrahlung rate. We find the opposite -- quantum overlap of bremsstrahlung with pair production significantly *increases* the bremsstrahlung rate compared to the LPM calculation -- and we verify our qualitative arguments with an analytic calculation of the effect.

    hep-phnucl-thJHEP(2026)·3 citations
27. 27*

    Pion dark matter in a $\theta$ vacuum: a thermal relic with sharp velocity-dependent self-interactions

    Camilo García-Cely🇪🇸 · Giacomo Landini🇪🇸 · Luca Marsili🇪🇸 · Óscar Zapata🇨🇴

    As recently proposed, a non-vanishing topological angle may play a central role in QCD-like theories of dark matter (DM). In this work, we introduce a dark photon portal to the Standard Model in order to establish thermal equilibrium in the early Universe, and discuss the ensuing phenomenological constraints, including the stability of DM. The resulting dynamics accounts for the observed DM relic abundance and yields velocity-dependent DM self-interactions in astrophysical halos. Due to the sharp velocity dependence arising from a Breit-Wigner resonance, dedicated studies are required to assess the gravothermal evolution in detail, especially in the core-collapse regime. This is particularly timely in light of self-interacting DM interpretations of strong-lensing systems such as SDSS J0946+1006, which can be naturally explained within our framework.

    hep-phastro-ph.COastro-ph.GAJHEP(2026)·8 citations
28. 28*

    Environmentally-induced chaos: Extreme-mass-ratio systems of rotating black holes in astrophysical environments

    Kyriakos Destounis🇵🇹 · Pedro G. S. Fernandes🇩🇪

    Extreme-mass-ratio inspirals, in which a stellar-mass object orbits a supermassive black hole, are prime sources of millihertz gravitational waves for upcoming space-based detectors. While most studies assume idealized vacuum backgrounds, realistic extreme-mass-ratio binaries are embedded in astrophysical environments such as accretion disks, stellar clusters, or dark matter spikes, disks, and halos, which can significantly alter the orbital dynamics. We explore bound geodesics around general-relativistic solutions describing rotating black holes surrounded by matter halos for the first time, mapping how environmental effects interfere with the spacetime symmetries of vacuum spinning (Kerr) black holes. In particular, we find that the loss of a Carter-like constant leads to geodesic non-integrability and the onset of chaos. This manifests through the formation of resonant islands and chaotic layers around transient orbital resonances in phase space--features that are otherwise completely absent in integrable Kerr geodesics. Resonant islands, which are extended, non-zero volume regions in phase space, encapsulate periodic orbit points. Non-integrability dictates that all geodesics inside the resonant island share the periodicity of the resonance. Thus, the lifespan of resonances around non-Kerr objects can be significantly enhanced beyond the predicted lifetime of Kerr resonances. Consequently, these effects can leave distinct imprints on gravitational-wave signals, with significant implications for gravitational-wave modeling and parameter inference of astrophysical extreme-mass-ratio inspirals.

    ↳ gr-qcastro-ph.GAastro-ph.HEhep-ph+1PRD(2026)·23 citations
29. 29*

    $F$-term Multi-Field Inflation in Supergravity without Stabiliser Superfields

    Jinn-Ouk Gong🇰🇷 · Sergei V. Ketov🇯🇵 · Takahiro Terada🇯🇵

    Realising $F$-term slow-roll inflation in supergravity is non-trivial due to the well-known $\eta$-problem. The common strategy to solve the problem is to impose a shift symmetry on the Kähler potential, but this often leads to a negative potential in the large-field regime. To avoid negative potentials, an additional superfield called the stabiliser is usually added with a desired interaction. An alternative mechanism in supergravity, avoiding the use of a stabiliser superfield, was earlier proposed by two of us in the setup with a single chiral superfield having inflaton and goldstino amongst its field components. In this work, we extend that alternative mechanism to multi-superfield models of inflation, thereby providing a generic framework for embedding a wide class of single- and multi-field inflation models into supergravity. We illustrate our approach by several concrete examples of multi-field inflation and clarify the conditions required to avoid tachyonic instabilities during multi-field evolution. Our proposal significantly broadens the theoretical landscape of $F$-term inflation models in supergravity.

    ↳ hep-thastro-ph.COgr-qchep-phJHEP(2025)·2 citations
30. 30*

    Two-particle number and transverse momentum balance function with event topology in pp collisions at $\sqrt{s}=13$ TeV

    Subash Chandra Behera🇮🇹 · Arvind Khuntia🇮🇹

    The first study of charge-dependent two-particle differential number ($B$) and momentum balance functions ($P_2^{CD}$) with respect to an event shape variable, transverse spherocity, is reported. Results are presented from PYTHIA8 and EPOS-LHC model calculations in proton-proton (pp) collisions at $\sqrt{s}=13$ TeV. To distinguish between back-to-back jet-like topologies and isotropic events, low and high transverse spherocity values are chosen. The correlation functions are measured as a function of averaged charged-particle multiplicity ($⟨N_{ch}⟩$) in relative pseudorapidity ($\Delta \eta$) and relative azimuthal angle ($\Delta \varphi$) with $|\eta |<2.4$ and $0.2<p_{\mathrm{T}}<2.0$ GeV. A narrowing of the balance function width is observed in $\Delta \eta$ and $\Delta \varphi$ from low- to high-multiplicity collisions. Wider balance functions are found in isotropic events as compared to jet-like events. However, for the momentum correlations, a nearly flat dependence is observed with $⟨N_{ch}⟩$. This study investigates charge conservation mechanisms and their correlations for events classified with jet-like and isotropic topologies. To isolate medium-driven effects, we compare EPOS-LHC with its hydrodynamic core enabled and disabled and observed narrowing patterns in $B$ and $P_2^{CD}$ as a quantitative handle on radial-flow-induced localization of charge-balancing pairs.

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

    Machine learning topological defect formation

    Fumika Suzuki🇺🇸 · Ying Wai Li · Wojciech H. Zurek🇺🇸

    According to the Kibble-Zurek mechanism (KZM), the density of topological defects created during a second-order phase transition is determined by the correlation length at the freeze-out time. This suggests that the final configuration of topological defects in such a transition is largely established during the impulse regime, soon after the critical point is traversed. Motivated by this, we conjecture that machine learning (ML) can predict the final configuration of topological defects based on the time evolution of the order parameter over a short interval in the vicinity of the critical point, well before the order parameter settles into the emerging new minima resulting from spontaneous symmetry breaking. Furthermore, we show that the predictability of ML also follows the power law scaling dictated by KZM. We demonstrate these using a Recurrent Neural Network.

    ↳ cond-mat.stat-mechgr-qchep-phhep-th+12 citations
32. 32*

    Three-dimensional trapping of circular Rydberg atoms by a superimposed vortex light beam

    Yi Liao🇨🇳 · Hao-Lin Wang🇨🇳 · Pengcheng Zhao🇨🇳

    We propose to trap circular Rydberg atoms (CRAs) by a ponderomotive potential well formed with a superimposed vortex light beam. We calculate analytically the ponderomotive potential energy for a Bessel vortex light beam. We work out a corrected version of the classical circular orbit approximation for a CRA which fits the exact result much better than the usual approximation. We reveal the three-dimensional characteristics of the potential well for some benchmark values of the CRA principal quantum number and beam parameters such as the frequency, the opening angle and topological charge of the vortex. We investigate how we can achieve similar trapping effects for different principal quantum numbers by varying beam parameters. The potential provides a lattice structure in the beam axis where one CRA could be trapped at each lattice site.

    ↳ physics.atom-phhep-phCommun.Theor.Phys.(2026)·0 citations
33. 33*

    On cusps in the ${\eta }^{\prime }$ potential

    Ryuichiro Kitano🇯🇵 · Ryutaro Matsudo🇯🇵 · Lukas Treuer🇯🇵

    The large $N$ analysis of QCD states that the potential for the ${\eta }^{\prime }$ meson develops cusps at ${\eta }^{\prime }=\pi /N_f$, $3\pi /N_f$, $\cdots$, with $N_f$ the number of flavors. Furthermore, the recent discussion of generalized anomalies tells us that even for finite $N$ there should be cusps if $N$ and $N_f$ are not coprime, as one can show that the domain wall configuration of ${\eta }^{\prime }$ should support a Chern-Simons theory on it, i.e., domains are not smoothly connected. On the other hand, there is a supporting argument for instanton-like, smooth potentials of ${\eta }^{\prime }$ from the analyses of softly-broken supersymmetric QCD for $N_f=N-1$, $N$, and $N+1$. We argue that the analysis of the $N_f=N$ case should be subject to the above anomaly argument, and thus there should be a cusp; while the $N_f=N\pm 1$ cases are consistent, as $N_f$ and $N$ are coprime. We discuss how this cuspy/smooth transition can be understood. For $N_f<N$, we find that the number of branches of the ${\eta }^{\prime }$ potential is $\gcd (N,N_f)$, which is the minimum number allowed by the anomaly. We also discuss the condition for s-confinement in QCD-like theories, and find that in general the anomaly matching of the $\theta$ periodicity indicates that s-confinement can only be possible when $N_f$ and $N$ are coprime. The s-confinement in supersymmetric QCD at $N_f=N+1$ is a famous example, and the argument generalizes for any number of fermions in the adjoint representation.

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

    Self-regularized entropy: What does black hole entropy predict for tests of Kerr no-hair theorem?

    Shokoufe Faraji🇨🇦 · Niayesh Afshordi🇨🇦

    We compute the canonical, or brick-wall, entropy of a massless scalar field in a quantum black hole model whose strong field exterior is described phenomenologically by the static $q$-metric, also known as the Zipoy-Voorhees metric. This geometry is an exact vacuum deformation of Schwarzschild with a small quadrupolar distortion parameter, $q$. Using WKB counting of trapped near horizon cavity modes, we show that this deformation changes the near horizon density of states so that the usual Schwarzschild brick-wall ultraviolet divergence is self-regularized, eliminating the need for an ad hoc proper distance cutoff within the perturbative regime studied here. Treating the Hawking temperature and Bekenstein-Hawking entropy of a Schwarzschild black hole of the same mass as external thermodynamic benchmarks, we obtain an analytic entropy-motivated deformation scale, $|q|\sim 0.2$, across the stellar-to-supermassive black hole mass range. Through a stationary extension, this scale maps phenomenologically onto percent-to-tens-of-percent violations of the Kerr multipole relations, providing observational targets for ngEHT imaging, LISA extreme mass ratio inspirals, and third generation ground based gravitational wave tests.

    ↳ gr-qcastro-ph.HEhep-phhep-thClass.Quant.Grav.(2026)·1 citation
35. 35*

    Lee-Yang-zero ratio method in three-dimensional Ising model

    Tatsuya Wada🇯🇵 · Masakiyo Kitazawa🇯🇵 · Kazuyuki Kanaya🇯🇵

    By performing Monte Carlo simulations of the three-dimensional Ising model, we apply the recently proposed Lee-Yang-zero ratio (LYZR) method to determine the location of the critical point in this model. We demonstrate that the LYZR method is as powerful as the conventional Binder-cumulant method in studying the critical point, while the LYZR method has the advantage of suppressing the violation of the finite-size scaling and non-linearity near the critical point. We also achieve a precise determination of the values of the LYZRs at the critical point, which are universal numbers. In addition, we propose an alternative method that uses only a single Lee-Yang zero and show that it is also useful for the search for the critical point.

    ↳ cond-mat.stat-mechhep-lathep-phphysics.comp-phJ.Phys.Soc.Jap.(2026)·3 citations
36. 36*

    Mineral Detection of Neutrinos and Dark Matter 2025 Proceedings

    Shigenobu Hirose🇯🇵 · Patrick Stengel🇮🇹 · Natsue Abe🇯🇵 · Daniel Ang · Lorenzo Apollonio🇮🇹 · Gabriela R. Araujo🇨🇭 · Yoshihiro Asahara🇯🇵 · Laura Baudis🇨🇭 · Pranshu Bhaumik · Nathaniel Bowden🇺🇸 · Joseph Bramante🇨🇦 · Lorenzo Caccianiga🇮🇹 and 61 other authors

    The third ``Mineral Detection of Neutrinos and Dark Matter'' (MD$\nu$DM'25) meeting was held May 20-23, 2025 in Yokohama, Japan, hosted by the Yokohama Institute for Earth Sciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC). These proceedings compile contributions from the workshop and update the progress of mineral detector research. MD$\nu$DM'25 was the third such meeting, following the first in October of 2022 held at the IFPU in Trieste, Italy and the second in January of 2024 hosted by the Center for Neutrino Physics at Virginia Tech in Arlington, USA. Mineral detectors record and retain damage induced by nuclear recoils in synthetic or natural mineral samples. The damage features can then be read out by a variety of nano- and micro-scale imaging techniques. Applications of mineral detectors on timescales relevant for laboratory experiments include reactor neutrino monitoring and dark matter detection, with the potential to measure the directions as well as the energies of the induced nuclear recoils. For natural mineral detectors which record nuclear recoils over geological timescales, reading out even small mineral samples could be sensitive to rare interactions induced by astrophysical neutrinos, cosmic rays, dark matter and heavy exotic particles. A series of mineral detectors of different ages could measure the time evolution of these fluxes, offering a unique window into the history of our solar system and the Milky Way. Mineral detector research is highly multidisciplinary, incorporating aspects of high energy physics, condensed matter physics, materials science, geoscience, and AI/ML for data analysis. Although realizing the scientific potential of mineral detectors poses many challenges, the MD$\nu$DM community looks forward to the continued development of mineral detector experiments and the possible discoveries that mineral detectors could reveal.

    ↳ physics.ins-detastro-ph.COastro-ph.IMhep-ex+16 citations
37. 37*

    $\Xi NN$ three-baryon force from SU(3) chiral effective field theory: A femtoscopic study

    Gen Uratsu🇯🇵 · Tokuro Fukui🇯🇵 · Kazuyuki Ogata🇯🇵

    Background: The development of SU(3) chiral effective field theory has opened the way to a systematic exploration of three-baryon forces (3BFs), a key ingredient in hypernuclear and dense matter physics. However, $\Xi NN$ 3BF based on SU(3) chiral EFT has not been studied until now. Purpose: We apply SU(3) chiral EFT to derive $\Xi NN$ potentials in momentum space. Then, we investigate how the $\Xi NN$ 3BF affects the correlation function of deuteron--${\Xi }^{-}$ pair created through heavy-ion collisions. Methods: To reduce the number of low-energy constants involved in the $\Xi NN$ potentials, we employ the decuplet saturation approximation, by which only two of them remain unconstrained. The deuteron--${\Xi }^{-}$ scattering is treated as an effective two-body problem with the $\Xi NN$ 3BF incorporated into the potential between the deuteron and ${\Xi }^{-}$. Results: We found that the effect of the $\Xi NN$ 3BF on the deuteron--${\Xi }^{-}$ correlation function is at most about 4\%. This small effect is not primarily due to the loosely-bound nature of the deuteron. Instead, this is because the deuteron and ${\Xi }^{-}$ interact with each other mainly at low momentum, corresponding to peripheral scattering, where the influence of the $\Xi NN$ 3BF is limited. Conclusions: Since the correlation function shows limited sensitivity to the short-range 3BF, complementary approaches may be necessary.

    ↳ nucl-thhep-phnucl-exPRC(2026)·0 citations
38. 38*

    Medium effects on the electromagnetic form factors of the $\rho$ meson

    Parada T. P. Hutauruk🇰🇷 · Terry Mart🇮🇩 · Kazuo Tsushima🇧🇷

    The dynamics of partons inside the light $\rho$ meson is found to be essential for its properties and internal structure, both in free space and in the nuclear medium. In this paper, we systematically investigate the in-medium structure changes of ${\rho }^{+}$ mesons within the covariant Nambu-Jona-Lasinio (NJL) model, utilizing the Schwinger proper-time regularization scheme. We solve the Bethe-Salpeter equations to guarantee the bound meson-state condition. At the quark level, the nuclear medium effects are also derived within the same NJL model to maintain a consistent approach with the in-medium ${\rho }^{+}$ meson electromagnetic form factors. To this end, we analyze the spacelike electromagnetic form factors of the ${\rho }^{+}$ meson in free space and in a nuclear medium. We find that the charge radius and quadrupole moment of the ${\rho }^{+}$ meson increase with increasing nuclear matter density, while the magnetic moment decreases, in agreement with the existing previous theoretical predictions. The enhancement of the ${\rho }^{+}$ meson charge radius at normal density relative to that in free space is about 11\% (0.08 fm), while the reduction of ${\rho }^{+}$ meson magnetic moment is about 8\% (0.20 ${\mu }_N$). Our predictions for the charge radius, magnetic moment, and quadrupole moment of the ${\rho }^{+}$ meson in both free space and nuclear medium, remain challenging to be verified experimentally.

    ↳ nucl-thhep-phPRD(2025)·7 citations
39. 39*

    Heavy quarkonia and new hadrons with two heavy quarks

    Yuping Guo🇨🇳 · Chang-Zheng Yuan🇨🇳

    We give a pedagogical introduction to heavy quarkonia -- bound states of a heavy quark and its antiquark (e.g., charmonium $c\bar{c}$, bottomonium $b\bar{b}$) -- as well as to the exotic hadrons containing two heavy quarks that have been discovered since 2003. The review covers the foundational discoveries ($J/\psi$ and ${\rm Y}$), basic properties, spectroscopy interpreted via potential models, production mechanisms at colliders, and decay modes. A significant focus is placed on the so-called ``$XYZ$" states -- particles like the $X(3872)$, $Y(4260/4230)$, $Z_c(3900)$, and $P_c$ -- whose properties defy conventional quark model expectations. These states, considered candidates for hybrids, multi-quark states, hadronic molecules, or hadroquarkonia, provide unprecedented probes of non-perturbative QCD and challenge our understanding of quark confinement and hadron formation. The chapter summarizes the current experimental landscape and highlights key open questions driving future research in hadron spectroscopy.

    ↳ hep-exhep-ph3 citations
40. 40*

    New Interpretations of the Cosmological Preference for a Negative Neutrino Mass

    Peter W. Graham🇺🇸 · Daniel Green🇺🇸 · Joel Meyers🇺🇸

    Recent observations of the cosmic microwave background (CMB) and baryon acoustic oscillations (BAO) show some tension with a $\Lambda$CDM cosmology. For one, the cosmological parameters determined by the CMB are at odds with the expansion history determined by latest BAO measurements. In addition, the combined data has placed uncomfortably strong constraints on neutrino mass. Both effects can be interpreted as negative neutrino mass, one describing the change to the expansion history and the other one describing enhanced lensing. In this paper, we show the current tensions can be solved with a single change either to the lensing of the CMB or the expansion of the universe. We show additional lensing could arise from a variety of models with new light fields. However, these models rarely give the same signal in temperature and polarization, giving a concrete test of the scenario. Alternatively, dark sector models can explain the changes to the expansion by changing the evolution of the matter density. These models introduce new forces, giving rise to long range signals in the three-point statistics of galaxies. We discuss a range of other examples which all illustrate the pattern that additional signals should appear if these tensions are explained by beyond the Standard Model physics.

    ↳ astro-ph.COhep-phhep-thPRD(2026)·28 citations
41. 41*

    System size and event shape dependence of particle-identified balance functions in proton-proton collisions at $\sqrt{s}=13$ TeV using PYTHIA 8 and EPOS models

    Subash Chandra Behera🇮🇹 · Arvind Khuntia🇮🇹

    We investigate charge balance functions for pion, kaon, and proton pairs in proton-proton (pp) collisions at $\sqrt{s}=13$ TeV using Monte Carlo models, PYTHIA8 and EPOS-LHC, with transverse spherocity to classify event topology and charged-particle multiplicity to select system size. Simulations with PYTHIA8 and EPOS-LHC reveal that balance-function widths in rapidity and azimuthal angle depend on multiplicity and event shape. In PYTHIA8, widths decrease monotonically with multiplicity, consistent with local charge conservation in a fragmentation-dominated scenario. In contrast, the EPOS-LHC model, especially when using the core corona implementation, exhibits a more intricate response, where the combined effects of hydrodynamic radial flow and longitudinal diffusion result in narrower azimuthal correlations and broader rapidity correlations. These features are characteristic signatures of collective dynamics, similar to those observed in heavy-ion collisions. Events with low spherocity, which are jet-like in nature, exhibit significantly narrower balance function widths compared to isotropic events with high spherocity, illustrating that event-shape selection provides clear sensitivity to the underlying dynamics of particle production in pp collisions. The species dependence and event-shape sensitivity of the balance-function widths provide information about the hadronization dynamics and collectivity in small systems. These results demonstrate that multidimensional, particle species dependent balance function measurements can disentangle the underlying mechanisms of charge correlations and medium-like behavior in high-multiplicity pp collisions.

    ↳ hep-exhep-phPRC(2026)·3 citations
42. 42*

    Constraints on Logarithmic Model Extensions of Symmetric Teleparallel Gravity

    Purnendu Karmakar🇪🇪 · Sandeep Haridasu🇮🇹 · Atsushi Nishizawa🇯🇵

    We address various cosmological phenomenologies in the symmetric teleparallel framework both in background and perturbation such as cosmic expansion, gravitational coupling constant, gravitational waves propagation. Focusing on logarithmic extensions of $f(Q)$ models, we performed Bayesian analysis using the most-recent cosmological data, DESI DR2, Pantheon+. We also utilized a compilation of redshift space distortions ($f{\sigma }_8$) dataset to constrain the growth of structures in each of the models modulated by the effective gravitational coupling. We find that our extended Logarithmic $f(Q)$ models are well-constrained by the current cosmological data and are able to describe the late-time cosmic acceleration. The inverse Logarithmic model we introduce is also able to accommodate a phantom-like dark energy equation of state at late times, which is consistent with the recent DESI DR2 observations. We report explicitly predictions for the effective gravitational coupling ($\mu$), and the amplitude damping parameter of gravitational wave ($\nu$) solely based on the background data, which can be tested against future observations. While the two Log-based extensions we have introduced here perform equivalently on the background level, they provide contrasting predictions for the evolution of effective Gravitational constant and propagation of gravitational waves, which should be constrained against the future perturbation data.

    ↳ astro-ph.COgr-qchep-ph7 citations
43. 43*

    Dynamics of the Fermion-Rotor System

    Vazha Loladze🇬🇧 · Takemichi Okui🇺🇸 · David Tong🇬🇧

    We explore the dynamics of the fermion-rotor system, a simple impurity model in d=1+1 dimensions that consists of a collection of purely right-moving fermions interacting with a quantum mechanical rotor localised at the origin. This was first introduced by Polchinski as a toy model for monopole-fermion scattering and is surprisingly subtle, with ingoing and outgoing fermions carrying different quantum numbers. We show that the rotor acts as a twist operator in the low-energy theory, changing the quantum numbers of excitations that have previously passed through the origin to ensure scattering consistent with all symmetries. We further show how generalisations of this model with multiple rotors and unequal charges can be viewed as a UV-completion of boundary states for chiral theories, including the well-studied 3450 model. We compute correlation functions between ingoing and outgoing fermions and show that fermions dressed with the rotor degree of freedom act as local operators and create single-particle states, generalising an earlier result obtained in a theory with a single rotor and equal charges. Finally, we point out a mod 2 anomaly in these models that descends from the Witten anomaly in 4d

    ↳ hep-thcond-mat.str-elhep-phJHEP(2026)·9 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.