Wed·Sep 24, 2025Wednesday·September 24, 2025

1. 01*

   Probing Quark Electromagnetic Properties via Entangled Quark Pairs in Fragmentation Hadrons at Lepton Colliders

   Qing-Hong Cao🇨🇳 · Guanghui Li🇨🇳 · Xin-Kai Wen🇨🇳 · Bin Yan🇨🇳

   Electromagnetic dipole interactions of light quarks induce distinct spin correlations in quark pairs produced at lepton colliders, favoring entangled spin-triplet state aligned along the $\hat{z}$ axis or spin-singlet state. These correlations lead to unique $\cos ({\varphi }_1-{\varphi }_2)$ azimuthal asymmetries in inclusive ${\pi }^{+}{\pi }^{-}$-dihadron pair production and in back-to-back hadron pairs ($\pi \pi ,K\pi ,KK$), which are absent in the SM. Using published Belle and BaBar measurements together with projected sensitivities based on ratios of azimuthal asymmetries, we demonstrate that these measurements provide significant constraints on light-quark dipole couplings, with a reduced dependence on poorly known nonperturbative fragmentation functions and free from contamination by other new physics effects. This approach offers a clean and novel probe of light-quark dipole interactions in collider experiments.

   hep-phhep-exnucl-exnucl-thRept.Prog.Phys.(2026)·17 citations
2. 02*

   Reach of e^+e^- Higgs factory for light higgsinos via electroweak precision observables and comparison with other future facilities

   Howard Baer🇺🇸 · Vernon Barger🇺🇸 · Natsumi Nagata🇯🇵 · Dibyashree Sengupta🇮🇹

   Light higgsinos with mass ~100-400 GeV are well-motivated from naturalness considerations within supersymmetric models. However, at hadron colliders such as CERN LHC, they are rather difficult to search for due to the small visible energy release from heavy higgsino decay to the lightest higgsino, assumed here to be the lightest SUSY particle (LSP). An alternative way to search for the sparticles of supersymmetry is via their virtual effects on electroweak precision observables (EWPO) such as the W boson mass or the effective weak mixing angle \sin^2\theta_{\rm eff}. We quantify the ability of an e^+e^- Higgs factory operating at \sqrt{s}\sim 90-250 GeV to indirectly detect higgsinos via EWPO in the so-called higgsino discovery plane. The latter allows one to compare the relative reach of LHC and high-lumi LHC with an e^+e^- Higgs factory and with a linear e^+e^- collider operating at \sqrt{s}~ 0.5 TeV.

   hep-phPLB(2026)·2 citations
3. 03*

   Exploring the Fundamental Properties of Neutrino from Oscillation Experiments

   Masoom Singh🇮🇳

   As physicists pursue precision neutrino measurements, complementary experiments covering varied oscillation landscapes have become essential for resolving current tensions in global fits. This thesis presents projected sensitivities and forecasted performance of two next-generation long-baseline experiments: DUNE and T2HK, through detailed simulations addressing fundamental questions including neutrino mass ordering, leptonic CP violation, and the octant of ${\theta }_{23}$. We demonstrate through simulated analyses that while each experiment alone faces inherent degeneracies, their complementary features enable breakthrough projected sensitivities in both standard oscillation parameter measurements and forecasted searches for new physics beyond the Standard Model. The combined simulation results reveal that DUNE-T2HK synergy will be crucial for achieving a comprehensive understanding of neutrino properties in the coming decade.

   hep-phhep-exphysics.ins-det1 citation
4. 04*

   Neural network expansion of Euclidean path integrals and its application to interacting scalar fields

   Gabor Balassa🇰🇷

   Studying phase transitions in interacting quantum field theories generally requires the numerical study of the dynamical system on a large lattice, which is, in most cases, computationally very challenging. In this work an alternative method is proposed to solve Euclidean path integrals in quantum field theories, using radial basis function-type neural networks. The method allows us to approximate observables in a very efficient manner, taking only seconds to do calculations that would otherwise take hours or even days with other existing methods. The model is used to describe phase transitions in the scalar ${\varphi }^4$ theory for a wide range of coupling strength. The obtained phase transition line is compared to previous lattice results, giving very good agreement between them.

   hep-phhep-latPRD(2026)·3 citations
5. 05*

   On Massive Neutrinos and Coherence in Neutrino Oscillations

   Anca Tureanu🇫🇮

   We examine the central tenet of the current standard theory of neutrino oscillations, namely the assumption that neutrinos are emitted and detected as flavour neutrino states, which are coherent superpositions of massive neutrino states of different masses. We prove that all the quantum mechanical and quantum field theoretical arguments, including the invocation of the uncertainty principle and the wave packet description of massive neutrinos, entail the production of neutrinos as statistical ensembles of massive neutrino states. As the states in a statistical ensemble do not interfere, neutrino oscillations cannot be explained by the superposition of massive states. We point out that neutrino oscillations in vacuum can be consistently formulated in theories which include, among other assumptions, the premise that the asymptotic states are massless flavour neutrinos.

   hep-phhep-exhep-thNPB(2025)·1 citation
6. 06*

   Elliptical Polarization in Partial Wave Analysis of Two Spinless Meson Photoproduction

   Derek I. Glazier🇬🇧 · Vincent Mathieu🇪🇸

   Mathematical ambiguities in partial-wave analysis present a significant challenge to the extraction of resonance properties in hadronic reactions. Recent work has shown that while linear photon polarization can resolve continuous ambiguities in the photoproduction of two pseudoscalar mesons, a final complex conjugate ambiguity remains. In this work, we extend the partial-wave formalism to include circular and elliptical photon polarization. We demonstrate that the additional constraints provided by circularly polarized observables, which are sensitive to the imaginary parts of bilinear amplitude products, are sufficient to remove remaining mathematical ambiguities, yielding an improved partial-wave solution. Furthermore, we show that the resulting overconstrained system allows for a novel application: using the reaction dynamics themselves as a polarimeter. Using recent high-statistics data on rho(770) photoproduction from the GlueX experiment, we illustrate the viability of this technique in determining the degrees of beam polarization from the data. These results will benefit the next generation of photoproduction experiments at facilities such as Jefferson Lab and the future Electron-Ion Collider.

   hep-phnucl-exPRD(2025)·2 citations
7. 07*

   Cosmic-ray cooling by dark matter in astrophysical jets

   Dimitrios Kantzas🇫🇷 · Francesca Calore🇫🇷 · Marco Chianese🇮🇹

   Astrophysical jets from powerful active galactic nuclei (AGN) have recently been proposed as promising probes of dark matter (DM) in the sub-GeV mass range. AGN launch relativistic jets that accelerate cosmic rays (CRs) to very high energies, which can then interact with their surroundings and produce multiwavelength (MW) emission spanning from radio frequencies to TeV $\gamma$ rays. If DM consists of light particles, their interactions with CRs could lead to an additional cooling mechanism that modifies the expected MW emission. In this work, we analyse the MW spectrum of Markarian 421, a well-studied AGN, using a multizone leptonic jet model that includes the interactions between CR electrons and DM particles. For the first time, we account for the uncertainties in the astrophysical jet dynamics, which have been previously neglected when constraining the CR-DM interactions. By fitting simultaneously jet parameters and DM-electrons interactions, we use the MW data from \mkn to set constraints on the DM-induced CR cooling. We obtain 5$\sigma$ upper limit ${\sigma }_{\text{DM-e}}\lesssim 1\times 10^{-34}{\text{cm}}^2$ for a DM mass of $1\mathrm{MeV}$. We demonstrate that this is about a factor of 2--10 stronger than traditional approaches depending on DM mass. This improvement originates from having indeed considered the full multi-wavelength emission from the source, instead if a simplified approach. Properly accounting for degeneracies between jet dynamics and DM interactions is also key to deriving robust constraints on DM interactions.

   hep-phastro-ph.HEPRD(2026)·4 citations
8. 08*

   Collins-type fragmentation energy correlator in semi-inclusive deep inelastic lepton-hadron scattering

   Qing-Hong Cao🇨🇳 · Zhite Yu🇺🇸 · C.-P. Yuan🇺🇸 · Shutao Zhang🇨🇳 · Hua Xing Zhu🇨🇳

   We initiate a systematic study of fragmentation energy correlators (FECs), which generalize traditional fragmentation functions and encode non-perturbative information about transverse dynamics in parton fragmentation processes. We define boost-invariant, non-perturbative FECs and derive a corresponding collinear factorization formula. A spin decomposition of the FECs is carried out, analogous to that of transverse-momentum-dependent fragmentation functions. In this work we focus particularly on the Collins-type quark FEC, which is sensitive to chiral symmetry breaking and characterizes the azimuthal asymmetry in the fragmentation of a transversely polarized quark. We perform a next-to-leading-order calculation of the corresponding hard coefficient in semi-inclusive deep-inelastic scattering for the quark non-singlet component, thereby validating the consistency of our theoretical framework.

   hep-phJHEP(2026)·15 citations
9. 09*

   Soret and Dufour effects in hot and dense QCD matter

   Kamaljeet Singh🇮🇳 · Kangkan Goswami🇮🇳 · Raghunath Sahoo🇮🇳

   The gradients act as invisible engines of transport, converting microscopic imbalances into macroscopic flows, and thus providing deep insights into the dynamics of physical systems. Thermal gradients do not merely drive the flow of heat, but they also set the microscopic constituents of the system into motion. In such scenarios, the constituents of the system not only transport energy but also diffuse collectively under the influence of these gradients. For the very first time, we present a first-principles investigation of the Soret and Dufour effects in hot and dense quantum chromodynamics (QCD) matter. We use the relativistic Boltzmann transport equation under the relaxation time approximation. By incorporating chemical potential and temperature gradients into the kinetic theory framework, we derive explicit expressions for the Dufour coefficient, which quantifies the heat flow due to concentration gradients, and the Soret coefficient, which describes the particle diffusion induced by thermal gradients. These coupled-transport phenomena are traditionally studied in multi-component classical systems at low energy scales. In this study, we follow quasiparticle models for the deconfined phase and the hadron resonance gas model for the confined hadronic phase in the context of heavy-ion collisions. This study provides novel insights into the thermo-diffusion and diffusion-thermo phenomena and opens avenues for incorporating such effects in hydrodynamic modeling and transport simulations of QCD matter.

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

    Decay of a scalar condensate in two different approaches

    Ayuki Kamada🇵🇱 · Kodai Sakurai🇯🇵

    Decay of a scalar condensate via interactions with (quasi-)particles is of interest to many fields in physics, including cosmology. In cosmology, the decay of an inflaton condensate leads to the production of daughter particles and reheating of the Universe. In computing the decay rate, two quantum field theoretic approaches can be found in the literature: one is based on parametric resonance of mode functions of the daughter particle; another is based on the $S$-matrix of a coherent state and Feynman-diagrammatic perturbation theory. We modify the latter from the previous literature in a way that manifests what we are computing and does not include unwanted Feynman diagrams. We notice the equivalence of these two approaches and demonstrate it by explicitly computing the decay rate at lower orders in the double expansion of the amplitude of coherent oscillation (or narrow resonance) and velocity of the daughter particle.

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

    Constraining Multi-scalars models with colliders and Dark Matter

    Rafael Boto🇵🇹

    After the observation in 2012 of a new scalar particle closely resembling the Higgs boson of the Standard Model of particle physics, there is a general consensus that there must be Physics Beyond the Standard Model, with present experiments now dedicated to its discovery. Extending the scalar sector is motivated by key unresolved issues in particle physics including the need of new sources of Charge Parity violation,providing an explanation of the baryon asymmetry in the universe, or to explain Dark Matter, which comprises of order 85% of the matter content of the Universe. In this thesis, we focus on three Higgs doublets models (3HDM) and the constraints that need to be imposed. We add theoretical contributions for the consistency of the scalar potential, with boundedness from below and the global minimum. We consider all constraints for full phenomenological studies in models with different symmetries, studying their individual impact and attempting to distinguish the models based on data. We propose a model with CP violating coefficients, leading to Higgs couplings that significantly deviate from Standard Model values and remain allowed. To explore the parameter space of the model, we employ an efficient Machine Learning algorithm that finds new regions of parameter space and observable consequences, not found with previous techniques we developed and applied. The new techniques are applicable to any Physics Beyond the Standard Model scenario. We connect the scalar extensions with experimentally viable solutions to the Dark Matter problem. When building Dark Matter models, one often imposes conserved discrete symmetries to stabilize DM candidates. We consider a possibility with two candidates, and an alternative possibility of a conserved non-Abelian group leading to a viable DM, in an attempt to chart the limits of what Multi-Higgs Models can accommodate.

    hep-ph1 citation
12. 12*

    Tensorial charge assignments in unitary groups

    E. Castillo-Ruiz🇧🇷 · Henry Diaz🇧🇷 · V. Pleitez🇧🇷

    We present an index-based tensorial formulation for computing eigenvalues of charge operators acting on arbitrary tensor representations of unitary gauge groups. The construction follows directly from the action of Cartan generators on tensor products and the additivity of weights, leading to a compact operator acting on general \((i_p,i_q)\) tensors. This framework provides a practical bookkeeping tool for assigning charges to arbitrary-dimensional multiplets appearing in model building. Explicit applications to \(SU(2)\), \(SU(3)\), and \(SU(5)\) representations are discussed.

    hep-phhep-thmath-phmath.MPEPJC(2026)·0 citations
13. 13*

    Dijet Photoproduction in POWHEG BOX

    Alexander Feike🇩🇪 · Tomáš Ježo🇩🇪 · Michael Klasen🇩🇪

    Photoproduction processes have gained a renewed interest following the approval of the EIC, making their implementation in Monte Carlo event generators highly desirable. We present recent efforts to develop a POWHEG BOX extension simulating dijet production from direct and resolved photons at next-to-leading order in QCD merged to parton showers, employing the Weizsäcker-Williams Approximation. It will facilitate event generation for collisions involving leptons, protons and heavy ions. Thus, it will be particularly useful for the study of ultra-peripheral collisions at CERN's LHC and for making predictions relevant to BNL's EIC.

    hep-ph0 citations
14. 14*

    X-rays from Inelastic Dark Matter Freeze-in

    Gordan Krnjaic🇺🇸 · David McKeen🇨🇦 · Riku Mizuta🇨🇦 · Gopolang Mohlabeng🇨🇦 · David E. Morrissey🇨🇦 · Douglas Tuckler🇨🇦

    We study inelastic dark matter produced via freeze-in through a light mediator with a mass splitting below the electron-positron threshold. In this regime, the heavier dark matter state is naturally long-lived compared to the age of the Universe and decays to the lighter state in association with photons. Given a light mediator, the dark matter abundance is directly related to the decay rate of the heavier dark matter. We show that observations of photons from the galactic center can effectively probe inelastic dark matter freeze-in with mediators at the $100\mathrm{MeV}$ scale and dark matter at the $\mathrm{GeV}$ scale.

    hep-phastro-ph.COPRD(2025)·6 citations
15. 15*

    Bayesian Constraints on Pre-Equilibrium Jet Quenching and Predictions for Oxygen Collisions

    Daniel Pablos🇪🇸 · Adam Takacs🇩🇪

    The contrast between the as-yet unmeasurable energy-loss effects in proton-nucleus collisions and the striking magnitude of the so-called high-momentum flow coefficients challenges our understanding of jet quenching mechanisms in large nucleus-nucleus collisions when applied to smaller systems. Intermediate-sized, light ion collisions will offer key insight into the system-size dependence of the interplay between jet energy loss and jet flow effects. To make quantitative predictions, we extend a semi-analytic jet quenching framework by coupling it to state-of-the-art event-by-event hydrodynamics and, for the first time, incorporate pre-equilibrium energy loss via the hydrodynamic attractor. A Bayesian analysis shows that an early-time onset of energy loss is compatible with RHIC and LHC measurements of jet suppression and jet elliptic flow in large systems, as well as hadron suppression, with the exception of hadron elliptic flow. Using these constraints, we predict both hadron and jet quenching observables in oxygen-oxygen collisions, finding sizable energy loss that exceeds the no-quenching baseline.

    hep-phhep-exhep-thnucl-ex+1PRC(2026)·25 citations
16. 16*

    The Pareto Frontier of Resilient Jet Tagging

    Rikab Gambhir🇺🇸 · Matt LeBlanc🇺🇸 · Yuanchen Zhou🇺🇸

    Classifying hadronic jets using their constituents' kinematic information is a critical task in modern high-energy collider physics. Often, classifiers are designed by targeting the best performance using metrics such as accuracy, AUC, or rejection rates. However, the use of a single metric can lead to the use of architectures that are more model-dependent than competitive alternatives, leading to potential uncertainty and bias in analysis. We explore such trade-offs and demonstrate the consequences of using networks with high performance metrics but low resilience.

    hep-phcs.LGhep-ex8 citations
17. 17*

    Towards the Parametric Renormalization of the S-matrix -- I

    Pinaki Banerjee🇮🇳 · Harsh🇮🇳 · Alok Laddha🇮🇳

    Zimmermann's forest formula is the corner stone of perturbative renormalization in QFT. By renormalizing individual Feynman graphs, it generates the UV finite S-matrix. This approach to renormalization makes the graph and all its forests center pieces in the theory of renormalization. On the other hand the positive geometry program delegate the role of Feynman graphs as secondary to the amplitude itself, which are generated by canonical forms associated to positive geometries. State of the art in this program is the convergence of S-matrix theory in local QFTs and string theory as the scattering amplitudes in QFT arise as integrals over certain moduli spaces. These integrals are known as curve integrals. For theories such as $\text{Tr}({\Phi }^3)$ theory with massive colored scalars, these integrals are divergent in the UV and have to be regularized. It is then natural to ask if there is a ``forest-like formula'' for these integrals which produce a renormalized amplitude without needing to explicitly invoke the forests associated to divergent subgraphs. In this paper, we initiate such a program by deriving forest-like formula for planar massive $\text{Tr}({\Phi }^3)$ amplitudes in $D=4$ dimensions. Our analysis relies on the insightful manifestation of the forest formula derived by Brown and Kreimer in \cite{Brown:2011pj}, that lead us to a definition of ``tropical counter-term'' for the bare amplitude.

    ↳ hep-thhep-phmath-phmath.MP1 citation
18. 18*

    Exploring Black Hole Environments

    Thomas F.M. Spieksma🇩🇰

    The past decade has transformed our ability to observe the Universe. Via gravitational waves, merging black holes and neutron stars can now be directly detected, offering unprecedented opportunities to test General Relativity and explore astrophysics in a new way. Driven by this breakthrough, the next generation of detectors is being developed to observe a wider range of sources with greater precision, ushering in a new era in gravitational-wave astronomy: leveraging black holes as probes of new physics. This thesis investigates how astrophysical environments, such as plasma, dark-matter structures, and clouds of ultralight bosons, affect black holes and their gravitational-wave signatures. After a short overview of gravitational-wave astrophysics, I study three classes of scenarios. (i) Isolated black holes: I examine boson clouds around black holes, their electromagnetic couplings and the role of surrounding plasma. (ii) Ringdown: I show that plasma can strongly modify the ringdown of charged black holes, whereas realistic dark-matter halos produce no detectable deviations even for next-generation detectors. (iii) Inspiral: for extreme-mass-ratio inspirals with boson clouds, I find that orbital resonances typically destroy the cloud unless the orbit is nearly counter-rotating, yielding new and exciting observational signatures. Entering the relativistic regime, I develop a self-consistent perturbative framework to model generic environments in extreme-mass-ratio binaries and apply it to the boson-cloud case. Finally, I construct a model for binaries repeatedly crossing active galactic-nucleus disks and track their long-term orbital evolution. The results of this thesis show how black hole environments shape gravitational-wave signals and open avenues for testing new physics with future observatories such as LISA or the Einstein Telescope.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-ph+11 citation
19. 19*

    Charm quark evolution in the early stages of heavy-ion collisions

    Mayank Singh🇺🇸 · Manu Kurian🇮🇳 · Björn Schenke🇺🇸 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦

    Heavy quarks are predominantly generated at the initial stage of relativistic heavy-ion collisions such that heavy flavor observables have the potential to provide information on the pre-equilibrium medium dynamics. In this study, we investigate the sensitivity of D-meson $R_{AA}$ and $v_2$ to early-time charm quark dynamics in Pb+Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV. We employ the IP-Glasma+MUSIC+UrQMD framework to model the evolution of the bulk medium. Charm quarks are generated using PYTHIA with nuclear parton distribution functions and evolved using Langevin dynamics within MARTINI. We observe that even though there is significant momentum broadening in the earliest stage, D-meson $R_{AA}$ and $v_2$ are only weakly sensitive to pre-equilibrium interactions.

    ↳ nucl-thhep-phPRC(2026)·9 citations
20. 20*

    Listening to the long ringdown: A novel way to pinpoint the EOS in neutron-star cores

    Christian Ecker🇩🇪 · Tyler Gorda🇺🇸 · Aleksi Kurkela🇳🇴 · Luciano Rezzolla🇩🇪

    Gravitational waves (GWs) from binary neutron star (BNS) merger remnants complement constraints from the inspiral phase, mass-radius measurements, and microscopic theory by providing information about the neutron-star equation of state (EOS) at extreme densities. We perform general-relativistic simulations of BNS mergers using EOS models that span the uncertain high-density regime. We find a robust correlation between the ratio of energy and angular momentum lost during the late-time post-merger GW signal - the long ringdown - and the EOS at the highest densities in neutron star cores. Applying this correlation to post-merger GW signals reduces EOS uncertainty at several times saturation density, where no direct constraints currently exist.

    ↳ astro-ph.HEgr-qchep-phnucl-thEPJ Web Conf.(2026)·0 citations
21. 21*

    Semianalytic calculation of the gravitational wave spectrum induced by curvature perturbations

    Takahiro Terada🇯🇵

    The stochastic gravitational wave (GW) background is secondarily and inevitably induced by the primordial curvature perturbations beyond the first order of the cosmological perturbation theory. We analytically calculate the integration kernel of the power spectrum of the induced GWs, which is the universal part independent of the spectrum of the primordial curvature perturbations, in the radiation-dominated era and in the matter-dominated era. We derive fully analytic expressions of the GW spectrum when possible. As a minor update, we study the case of the top-hat function as the spectrum of the curvature perturbations. We also discuss generalization in the presence of multiple cosmological eras with different equations of state.

    ↳ gr-qcastro-ph.COhep-phhep-thSoryushiron Kenkyu(2026)·4 citations
22. 22*

    Constraining Axion-Like Particle mediated Dark Matter with Observational Constraints: A Statistical and Machine Learning Approach

    Prashant Thakur🇰🇷 · Aravind Taridalu🇮🇳 · Ishfaq Ahmad Rather🇩🇪 · Tanech Klangburam🇹🇭 · Chakrit Pongkitivanichkul🇹🇭

    We present a comprehensive study of axion-like particle (ALP) mediated dark matter (DM) effects on neutron star (NS) structure within a relativistic mean-field framework with non-linear mesonic interactions constrained by nuclear and astrophysical data. We explore DM masses \(m_\chi \in [0,1000]\,\mathrm{GeV}\) and Fermi momenta \(q_f \in [0,0.06]\,\mathrm{GeV}\), generating over 30{,}000 equations of state using two representative hadronic models, a stiff EoS (EoS1) and a soft EoS (EoS18), including a consistent crust description. A multi-level statistical filtering scheme based on voting, likelihood, and kernel density estimation is applied using constraints from radio and X-ray pulsars, GW170817, and the low-mass compact object HESS~J1731$-$347. We find that models satisfying the PSR~J0614$-$3329 radius constraint automatically comply with the HESS bound, allowing ALP-mediated DM to explain low-mass compact objects while remaining consistent with \(2\,M_\odot\) NSs. For the stiff EoS, we obtain a lower bound \(m_\chi \gtrsim 43\,\mathrm{GeV}\), with preferred values \(q_f = 0.034^{+0.020}_{-0.012}\) and \(m_\chi \in [101,949]\,\mathrm{GeV}\), while the soft EoS yields no strict lower bound, though large \(m_\chi\) and \(q_f\) are disfavored. We also develop a supervised interpolation model using \texttt{AutoGluon} to infer DM parameters from NS mass--radius curves, achieving \(R^2>0.998\), and show that \(m_\chi\) is mainly constrained by global radius ratios, whereas \(q_f\) is driven by the tidal deformability \(\Lambda_{1.4}\).

    ↳ astro-ph.HEhep-phPRD(2026)·5 citations
23. 23*

    Finite-temperature Yang-Mills theories with the density of states method: towards the continuum limit

    Ed Bennett🇬🇧 · Biagio Lucini🇬🇧 · David Mason🇩🇪 · Maurizio Piai🇬🇧 · Enrico Rinaldi🇯🇵 · Davide Vadacchino🇬🇧 · Fabian Zierler🇬🇧

    A first-order, confinement/deconfinement phase transition appears in the finite temperature behavior of many non-Abelian gauge theories. These theories play an important role in proposals for completion of the Standard Model of particle physics, hence the phase transition might have occurred in the early stages of evolution of our universe, leaving behind a detectable relic stochastic background of gravitational waves. Lattice field theory studies implementing the density of states method have the potential to provide detailed information about the phase transition, and measure the parameters determining the gravitational-wave power spectrum, by overcoming some the challenges faced with importance-sampling methods. We assess this potential for a representative choice of Yang-Mills theory with $Sp(4)$ gauge group. We characterize its finite-temperature, first-order phase transition, in the thermodynamic (infinite volume) limit, for two different choices of number of sites in the compact time direction, hence taking the first steps towards the continuum limit extrapolation. We demonstrate the persistence of non-perturbative phenomena associated to the first-order phase transition: coexistence of states, metastability, latent heat, surface tension. We find consistency between several different strategies for the extraction of the volume-dependent critical coupling, hence assessing the size of systematic effects. We also determine the minimum choice of ratio between spatial and time extent of the lattice that allows to identify the contribution of the surface tension to the free energy. We observe that this ratio scales non-trivially with the time extent of the lattice, and comment on the implications for future high-precision numerical studies.

    ↳ hep-latastro-ph.COhep-phPRD(2026)·7 citations
24. 24*

    Exact WKB Formulation of Quantization and Particle Production in Time-Dependent Backgrounds

    Ryo Namba🇯🇵 · Motoo Suzuki🇮🇹

    Divergence in perturbative expansions is where interesting physics takes place. Particle production on time-dependent backgrounds, as one such example, is interpreted as transition from one vacuum to another. Vacuum is typically defined as an asymptotic state in which the WKB approximation is valid. The use of the WKB method, however, poses several conceptual and computational issues, as the WKB series is divergent in general, quantization is insensitive to higher orders in the series, and the global behavior of solutions cannot be captured. Exact WKB analysis is a powerful resummation technology that provides an analytical tool for a global structure of exact solutions to overcome these problems. In this paper, we establish quantization by fully employing the exact WKB solutions as mode functions and by defining the vacua with respect to them. We provide a self-contained exact WKB formulation to obtain evolution matrices without resorting to the use of known special functions and without approximations. We find that the quantity called Voros coefficient plays an important role to re-normalize the exact WKB solutions compatible with asymptotic states. We show that the ambiguity that coexists with nontrivial Voros coefficients is eliminated by requiring physical quantization conditions. Our formalism provides a conceptual as well as practical framework to upgrade our treatment of quantization and particle production. Combined with other approximating techniques, it can form a basis to tackle a broad class of problems that are beyond technical ability of the existing formulations.

    ↳ hep-thastro-ph.COgr-qchep-ph3 citations
25. 25*

    Analytical results for large-$N_c$ scalar QCD${}_2$

    Pavel Meshcheriakov🇺🇸

    We study large-$N_c$ scalar QCD${}_2$, a $1+1$-dimensional confining gauge theory with fundamental scalar quarks, whose meson spectrum is governed by a Bethe-Salpeter equation structurally parallel to the 't Hooft equation. Exploiting this structural analogy, we develop a nonperturbative analytic framework, based on integrability and inspired by the Fateev-Lukyanov-Zamolodchikov (FLZ) method, originally devised for the 't Hooft model and later extended in our previous works. Notably, the same Bethe-Salpeter equation also arises in the description of interchain mesons in the doubled Ising model coupled via a spin-spin interaction term. Within the FLZ approach, we find spectral sums and derive a systematic large-$n$ WKB expansion for the meson spectrum. The analytic results reproduce the expected behavior in key asymptotic regimes, such as the near-critical limit $m\to g/\sqrt{\pi }$ and the heavy-quark regime $m\gg g$, and are in good agreement with numerical data. Finally, by analytically continuing the mass parameter into the complex plane, we uncover two infinite families of singularities where individual mesons become massless, suggesting a hidden connection to nontrivial Conformal Field Theories.

    ↳ hep-thcond-mat.stat-mechhep-phPRD(2025)·1 citation
26. 26*

    The Cosmic Rush Hour: Rapid Formation of Bright, Massive, Disky, Star-Forming Galaxies as Signatures of Early-Universe Physics

    Xuejian Shen🇺🇸 · Oliver Zier · Mark Vogelsberger🇺🇸 · Michael Boylan-Kolchin🇺🇸 · Lars Hernquist🇺🇸 · Sandro Tacchella🇬🇧 · Rohan P. Naidu

    Early JWST observations have revealed a high-redshift universe more vibrant than predicted by canonical galaxy-formation models within $\Lambda$CDM, showing an excess of ultraviolet(UV)-bright, massive, and morphologically mature galaxies. Departures from $\Lambda$CDM prior to recombination can imprint signatures on non-linear structure formation at high redshift. In this paper, we investigate one such scenario - Early Dark Energy, originally proposed to resolve the Hubble tension - and its implications for these high-redshift challenges. We present the first large-scale cosmological hydrodynamic simulations of these models. Modifications to the pre-recombination expansion history accelerate early structure formation and produce UV luminosity and stellar mass functions in excellent agreement with JWST measurements, requiring essentially no additional calibrations. Predictions converge to $\Lambda$CDM at lower redshifts ($z\lesssim 3$), thereby preserving all successes of $\Lambda$CDM. This model also accelerates the emergence of stellar and gaseous disks, increasing their number densities by $\sim 0.5$ dex at $z\simeq 6$-7, primarily due to the higher abundance of massive galaxies. Taken together, these results demonstrate how early-universe physics can simultaneously reconcile multiple high-redshift challenges and the Hubble tension while retaining the core achievements of $\Lambda$CDM. This opens a pathway to constraining a broad class of beyond-$\Lambda$CDM models with forthcoming observations.

    ↳ astro-ph.GAastro-ph.COhep-phMNRAS(2026)·8 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.