Thu·Nov 13, 2025Thursday·November 13, 2025

1. 01*

   Ward-Takahashi identity in the light-front formalism for a bound state of fermions

   Deepesh Bhamre🇧🇷 · J. P. B. C. de Melo🇧🇷

   We investigate the Ward-Takahashi identity at one-loop in the light-front (LF) formalism for a bound state of fermions. We consider a spinless bound state made up of two fermions in which the Ward-Takahashi identity is satisfied in the covariant formulation. Considering the same system in the light-front formalism, we investigate the proof of Ward-Takahashi identity by integrating the light-front energy component through the identification of the relevant ranges of the longitudinal LF momentum. We elucidate that the pair production diagram plays a crucial role in establishing the Ward-Takahashi identity. We also point out the necessity of taking into account the corresponding zero modes for truly establishing the Ward-Takahashi identity in the LF formalism.

   hep-phhep-thPRD(2026)·1 citation
2. 02*

   Correlations between heavy mesons and the creation of the charmonia, bottomonia, and $B_c$ mesons in high energy $pp$ collisions

   Jiaxing Zhao🇩🇪 · Joerg Aichelin🇫🇷 · Pol Bernard Gossiaux🇫🇷 · Klaus Werner🇫🇷

   The different QCD processes, which can produce a heavy quark-antiquark ($Q\bar{Q}$) pair, induce different correlations between the heavy quarks. Employing the EPOS4HQ event generator we study the consequences of these correlations and compare the calculation with experimental results on open and hidden heavy flavour mesons, measured in proton-proton (pp) collisions at RHIC and LHC energies. We find that the measured correlations between heavy mesons are a direct image of the different production mechanisms, which contribute also in a different way to the transverse momentum distribution of open and hidden heavy flavour mesons. The latter are calculated in a Wigner density approach which also enables to reproduce quantitatively the measured $B_c$ spectra. This agreement allows conclusions on the spatial distribution of the heavy quark creation processes.

   hep-phnucl-thPRD(2026)·8 citations
3. 03*

   Did our Universe Tunnel out of the Wrong Higgs Vacuum?

   Bibhushan Shakya🇩🇪

   This paper explores various aspects and implications of the initial configuration of the Standard Model (SM) Higgs field at the beginning of our Universe. It is well known that the SM Higgs field features a deeper, more stable minimum at large field values. While it is possible that our Universe began and remained in the electroweak vacuum at all times, this scenario is extremely fine-tuned from the point of view of initial conditions. This fine-tuning can be ameliorated by the exponential expansion of spacetime during inflation: intriguingly, this requires at least $\sim 40$ e-folds of inflation, tantalizingly close to the $50-60$ e-folds expected from horizon and flatness considerations. The Higgs could thus provide the reason for a prolonged epoch of inflation in our cosmic history. Otherwise, the most natural initial state corresponds to our Universe initialized in the more stable but "wrong" Higgs vacuum, and subsequently driven dynamically to the weak scale vacuum during reheating. An important, hitherto unexplored aspect of this dynamics is that the barrier between the two vacua persists when the electroweak vacuum becomes energetically favorable, becoming arbitrarily small as the temperature increases, and therefore triggers a first-order phase transition. This transition produces ultra-high (megahertz to gigahertz) frequency gravitational waves (GWs), serving as a challenging but unique SM target for GW experiments. Novel pathways for various beyond the Standard Model phenomena such as the production of dark matter and baryon asymmetry also become possible in this configuration.

   hep-phastro-ph.COhep-th8 citations
4. 04*

   Higgs Yukawa coupling constraints on a benchmark one-loop radiative mass model for the bottom, charm and tau

   Lucia Stockdale🇦🇺 · Raymond R. Volkas🇦🇺

   Measurements of Higgs boson Yukawa couplings to Standard Model (SM) fermions constrain radiative mass models for those species. Such models, motivated by the observed fermion mass hierarchy, act as foils for the SM tree-level mechanism: we cannot claim to have verified the standard mechanism if other possibilities also fit the data well. We construct a benchmark model which generates the top mass at tree level, and the bottom, charm, tau, and tau Dirac neutrino masses at one-loop level. Current theoretical and experimental constraints on the model, including from Higgs decays, demonstrate it possesses viable regions of parameter space. We show that future improvements to measurements will not be able to rule out the model, only increase the scale of new physics required, illustrating how difficult it will be to verify the SM fermion mass generation mechanism with great precision. As a bonus, a dark matter candidate is shown to be capable of reproducing the correct relic density within the permitted parameter space.

   hep-phPRD(2026)·2 citations
5. 05*

   Search for light Dark Sectors with GeV Muon Beams

   Zijian Wang🇨🇳 · Leyun Gao🇨🇳 · Zhuo Chen🇨🇳 · Cheng-en Liu🇨🇳 · Jinning Li🇨🇳 · Qite Li🇨🇳 · Chen Zhou🇨🇳 · Qiang Li🇨🇳 · Yu Xu🇨🇳 · Xueheng Zhang🇨🇳 · Liangwen Chen🇨🇳 · Zhiyu Sun🇨🇳 · Ce Zhang🇬🇧

   Sub-GeV light dark matter often requires new light mediators, such as a dark $Z$ boson in the $L_{\mu }-L_{\tau }$ gauge theory. We study the search potential for such a $Z^{\prime }$ boson via the process $\mu e^{-}\to \mu e^{-}X$, with $X$ decaying invisibly, in a muon on-target experiment using a high-intensity 1-10 GeV muon beam from facilities such as HIAF-HIRIBL. Events are identified by the scattered muon and electron from the target using silicon strip detectors in a single-station telescope system. Backgrounds are suppressed through a trained boosted decision tree (BDT) classifier, and activity in downstream subdetectors remains low. This approach can probe a $Z^{\prime }$ boson in the 10 MeV mass range with improved sensitivity. Nearly three orders of magnitude improvement is achievable with a full multi-telescope station system employing a 160 GeV muon beam at CERN, such as in the MUonE experiment.

   hep-phPRD(2026)·2 citations
6. 06*

   The color force acting on a quark in the pion and nucleon

   Wei-Yang Liu🇺🇸 · Edward Shuryak🇺🇸 · Ismail Zahed🇺🇸

   In the Operator Product Expansion (OPE) of hard scattering amplitudes, the twist-3 operators describe local colored Lorentz forces acting on a quark, thereby providing a measure of the strength of the gluon fields. Its value is directly accessible from the nucleon twist-3 polarized $g_2$-parton distribution function. In the semiclassical (instanton-based) QCD vacuum models, the leading non-perturbative contribution stems from correlated instanton-anti-instanton pairs, or molecules. We analyze the magnitude of the color force on a struck quark in light hadrons (pion and nucleon), in the context of the instanton liquid model (ILM). We derive explicitly the pertinent form factors associated with the color Lorentz force and show that they are intimately related to the pertinent hadronic gravitational and transversity form factors. Using the ILM enhanced by molecules, we detail the ensuing colored force distribution in the transverse plane for the luminal pions and nucleons. The results for the nucleons are in good agreement with those recently reported from a lattice collaboration.

   hep-phhep-lathep-thnucl-thPRD(2026)·4 citations
7. 07*

   Emergent Dark Matter

   Christian Canete🇦🇺 · Archil Kobakhidze🇦🇺

   We entertain the possibility that the phenomena typically attributed to dark matter may have a fundamentally emergent nature, rather than arising from new particle degrees of freedom. To illustrate this idea, we consider a field-theoretic model of a three-form gauge field coupled to a cosmological fluid composed of ordinary matter and radiation. In the absence of interactions, the 3-form gauge theory describes only a global, non-propagating state, which can be associated with dark energy. However, when coupled to the cosmic fluid, the theory gives rise to an emergent, dynamical in-medium state. We identify this emergent state of the 3-form gauge field with dark matter. Thus, our proposal provides a unified framework for the dark sector of the universe within the context of an interacting three-form gauge theory. Furthermore, we speculate that the three-form field may have a gravitational origin, potentially supported by the lepton-number asymmetry in the primordial plasma. If this scenario is correct, conventional direct and indirect searches for dark matter would likely be futile.

   hep-phastro-ph.COhep-thPLB(2026)·1 citation
8. 08*

   Analysis of the strong decays of the $Y(4660)$ in tetraquark scenario via the QCD sum rules

   Xiao-Song Yang🇨🇳 · Zhi-Gang Wang🇨🇳

   Motivated by the enigmatic vector charmonium-like states, we investigate the strong decay behaviors of four kinds of vector tetraquark states, which are possible candidates for the $Y(4660)$, within the framework of three-point QCD sum rules based on rigorous quark-hadron duality. We take into account the vacuum condensates up to dimension 5 on the QCD side, and obtain the hadronic coupling constants therefore the partial decay widths of those states. The predicted total width $61.5\pm 7.3\mathrm{MeV}$ is in excellent agreement with the experimental data for the $Y(4660)$, which supports its interpretation as a $[sc][\bar{s}\bar{c}]$ tetraquark state with the $J^{PC}=1^{--}$.

   hep-phCPC(2026)·1 citation
9. 09*

   No hidden physics in resonance pole residue phase

   S. Ceci🇭🇷 · R. Omerović🇧🇦 · H. Osmanović🇧🇦 · M. Uroić🇭🇷 · B. Zauner🇭🇷

   In hadron resonant scattering, there are four fundamental resonant parameters: real and imaginary part of the pole position, and the magnitude and the phase of the residue. Out of the four, the last one is the least understood. The search for the residue phase's physical meaning has focused on model-independent phases of the majority of the lowest-mass resonances. Here, we apply a simple mathematical identity to the amplitude in the complex plane to reveal the exact reason for the noticed regularity and show that there is no room for hidden physical variables in the residue phase.

   hep-phPLB(2026)·8 citations
10. 10*

    Impact of reactor antineutrinos on the neutrino floor in low-mass WIMP-like dark matter searches

    S. Das🇮🇳 · V. K. S. Kashyap🇮🇳 · B. Mohanty🇮🇳

    The sensitivity of conventional direct dark matter searches for weakly interacting massive particles (WIMPs) is ultimately limited by coherent elastic neutrino-nucleus scattering (CEvNS), which produces nuclear recoils indistinguishable from WIMP signals and defines the so-called neutrino floor. While the effects of solar neutrinos, geoneutrinos, diffuse supernova neutrinos, and atmospheric neutrinos have been extensively studied in this context, the contribution from reactor antineutrinos has received comparatively little attention. We present the first systematic evaluation of how reactor antineutrino fluxes, modeled as a function of reactor-detector distance, modify the neutrino floor for low-mass WIMP searches using SuperCDMS-like high-voltage germanium detectors. Both discovery-limit and opacity-based formulations of the neutrino floor are examined under consistent assumptions. We find that proximity to gigawatt-scale reactors within 10 km can raise the neutrino floor by up to a few orders of magnitude, significantly reducing the sensitivity to sub-10 GeV/c^2 dark matter. Beyond 100 km, the reactor contribution becomes negligible. These conclusions hold for both definitions of the neutrino floor and remain stable under reasonable variations in detector quenching, site-dependent geoneutrino flux, and reactor antineutrino flux uncertainties, emphasizing reactor proximity as a critical factor in site selection for future low-threshold dark matter experiments.

    hep-phastro-ph.HEhep-exPRD(2026)·1 citation
11. 11*

    Strongly intensive quantities for rapidity correlations of multiplicities

    Evgeny Andronov🇷🇺

    Studies of the phase diagram of strongly interacting matter created in nuclear collisions are typically carried out using event-by-event fluctuations. Well-known way to disentangle statistical and dynamical fluctuations is to construct special observables named strongly intensive which are free from trivial volume fluctuations. Within the color string model behavior of the second-order strongly intensive quantity $\Sigma$ is completely determined by the two-particle correlation function from a single string and the string fusion mechanism. In this paper, we analyze third-order strongly intensive observable for forward-backward rapidity correlations and test its behavior within the PYTHIA8 model.

    hep-phnucl-th0 citations
12. 12*

    Production of Light Dark Particles from Nonlinear Compton Scattering Between Intense Laser and Muon or Proton Beam

    Tong Li🇨🇳 · Kai Ma🇨🇳 · Man Yuan🇨🇳

    The laser of an intense electromagnetic field promotes the studies of strong-field particle physics in high-intensity frontier. Particle accelerator facilities in the world produce high-quality muon and proton beams. In this work, we propose the nonlinear Compton scattering to light dark particles through the collision between intense laser pulse and muon or proton beam. We take light dark photon and axion-like particle as illustrative dark particles. The cross sections of relevant nonlinear Compton scattering to dark photon or axion-like particle are calculated. We also analyze the background processes with missing neutrinos. The prospective sensitivity shows that the laser-induced process provides a complementary and competitive search of new invisible particles lighter than about 1 MeV.

    hep-phJHEP(2026)·1 citation
13. 13*

    Parametrisation scale invariance of Parton Distribution Function fits

    Ivan A. Godino · Eva D. Z. Groenendijk🇮🇹 · Tanjona R. Rabemananjara🇳🇱

    In global PDF analyses, parton distribution functions (PDFs) are parametrised at a fixed input scale $Q_0$ and evolved to higher scales using the DGLAP equations. Since QCD evolution is fully determined within perturbation theory, the fitted PDFs should, in principle, be independent of the arbitrary choice of $Q_0$. In this work, we test this within the NNPDF framework by performing a series of fits at different starting scales, namely $Q_0\in 1.0,1.25,1.5,1.65$ GeV. We find that the resulting PDFs are consistent within uncertainties and the fit quality remains stable across this range, therefore confirming the invariance of PDF determinations with respect to the choice of starting scale.

    hep-phhep-thPoS(2025)·0 citations
14. 14*

    Self-Interaction of Super-Resonant Dark Matter

    Shao-Song Tang🇨🇳 · Murat Abdughani🇨🇳

    The $\Lambda$CDM model, while successful on large cosmological scales, faces challenges on small scales. A promising solution posits that dark matter (DM) exhibits strong self-interaction, enhanced through the narrow resonance or Sommerfeld effects. We demonstrate that the ``super-resonance" phenomenon, combining these effects, significantly amplifies the DM self-scattering cross section, enabling strong self-interactions for DM candidates in the $\mathcal{O}(100)$ GeV mass range. This mechanism also enhances the DM annihilation cross section, causing early kinetic decoupling that renders the standard Boltzmann equation inadequate. By implementing coupled Boltzmann equations, we achieve precise calculations of the relic density for super-resonant DM, aligning with observational constraints.

    hep-phJHEP(2026)·0 citations
15. 15*

    A Unified Dark-Matter--Driven Relativistic Bondi Route to Black-Hole Growth from Stellar to Supermassive Scales

    Chian-Shu Chen🇹🇼 · Feng-Li Lin🇹🇼

    Observations of luminous quasars at $z\gtrsim 7$ reveal supermassive black holes (SMBHs) with inferred masses $M_{\mathrm{BH}}\sim 10^9{M}_{\odot }$ formed within the first $\sim 700$~Myr of cosmic history. Standard growth channels \textrm{ -- } Eddington-limited gas accretion and hierarchical mergers \textrm{ -- } face severe timescale restrictions. We consider a super-Eddington accretion mechanism aided by the Bondi accretion of a minimal model of self-interacting dark matter (SIDM). We demonstrate that in a {\it critical regime} with a near-relativistic sound speed, the Bondi accretion yields an accretion rate that depends only on the mass $m$ of SIDM, thus it is universal to the ambient environment. This critical accretion mechanism for $m\gtrsim 10^{-2}\mathrm{eV}$ can grow seeds as small as $10M_{\odot }$ primordial black holes (PBH) in the early Universe into $10^9$ \textrm{--} $10^{10}{M}_{\odot }$ SMBHs by $z\sim 7$ without fine-tuned environments. Therefore, given a mass distribution of PBHs and a value of $m$, the mass function of primary black holes at late time can be fully determined with masses ranging from stellar to SMBHs. This connects the microscopic physics of dark matter to astrophysical observations of black holes.

    hep-phastro-ph.COastro-ph.GAApJL(2026)·1 citation
16. 16*

    Compton Scattering Total Cross Section at Next-to-Next-to-Leading Order and Resummation of Leading Logarithms

    Hai Tao Li🇨🇳 · Yan-Qing Ma🇨🇳 · Cheng-Tai Tan🇨🇳 · Jian Wang🇨🇳 · Hong-Fei Zhang🇨🇳

    Compton scattering is a fundamental process in QED with broad applications, yet its theoretical description at high energies is challenged by substantial next-to-leading order (NLO) corrections arising from double-logarithmic enhancements. To address this, we report the first calculation of the next-to-next-to-leading order (NNLO) total cross section with full electron mass dependence. Our analysis reveals that the NNLO correction, albeit still containing double logarithms, is numerically small due to a suppressing prefactor. By identifying the origin of these logarithms in a kinematic regime featuring a Glauber electron exchange, we successfully resum the leading logarithmic series to all orders, obtaining a compact result in terms of a modified Bessel function. The all-order structure reveals a suppression mechanism, with double factorial terms in the denominator, which explains the negligible nature of higher-order contributions. The combination of our NNLO calculation and all-orders resummation delivers a reliable and precise prediction, poised to serve the needs of high-precision experiments in the foreseeable future.

    hep-phhep-exhep-thPRL(2026)·3 citations
17. 17*

    A Methodology for Developing Foundational Transformer Models in Collider Physics Analysis

    E. Abasov🇷🇺 · L. Dudko🇷🇺 · E. Iudin🇷🇺 · A. Markina🇷🇺 · P. Volkov🇷🇺 · M. Perfilov🇷🇺 · A. Zaborenko🇷🇺

    We present a methodology for training foundational transformer models capable of processing collider data with diverse kinematic signatures. Our universal foundation model is designed for simultaneous analysis of all processes involving from one to four top-quarks production with their corresponding background processes. The approach employs multi-task pre-training on combined datasets of simulated events, enabling the model to capture the full spectrum of interaction physics while extracting universal patterns across different final states prior to task-specific fine-tuning. This unified architecture eliminates the need for separate analysis frameworks for different final signatures and specific tasks. The transformer-based pre-training strategy explicitly preserves unique interaction patterns through adaptive attention mechanisms while establishing cross-process correlations. We plan to demonstrate how this architecture maintains sensitivity to rare high-multiplicity topologies (3t and 4t) without compromising performance on conventional channels ($t\bar{t}$, $tX$, $t\bar{t}H$), effectively bridging the gap between disparate analysis paradigms in collider physics.

    hep-phhep-ex0 citations
18. 18*

    Sensitivity of Standard Model Vacuum Stability to Enhanced Scalar Couplings: A Coupling Scan and its Implications for Radiatively Broken Electroweak Symmetry

    Farrukh A. Chishtie🇨🇦 · Sirous Homayouni🇺🇸

    We study how Standard Model vacuum stability depends on the Higgs quartic coupling at the electroweak matching scale, parameterized through a dimensionless enhancement factor $k={\lambda }_{\mathrm{enhanced}}(M_t)/{\lambda }_{\mathrm{SM}}(M_t)$, with the observed Higgs mass held fixed at $M_h=125$~GeV. This is a scan of the coupling itself, treated as a free parameter set by physics beyond the Standard Model, and is distinct from the Higgs-mass scan that underlies the conventional stability bound. Using the complete three-loop renormalization group equations including all gauge and Yukawa couplings, we find a critical threshold $k_{\mathrm{crit}}\approx 1.076$ separating the metastable Standard Model trajectory from absolutely stable trajectories. At this threshold the matching-scale coupling is $\lambda (M_t)\approx 0.135$, which reproduces the established three-loop absolute-stability boundary, providing an internal consistency check of the framework. The instability scale is highly sensitive to $k$ near the threshold, with a logarithmic susceptibility $d\ln {\Lambda }_I/d\ln k$ of order $10^3$ as $k\to k_{\mathrm{crit}}^{-}$, larger by two to three orders of magnitude than the analogous susceptibility of ${\Lambda }_{\mathrm{QCD}}$ to ${\alpha }_s(M_Z)$. For $k>k_{\mathrm{crit}}$ the vacuum is absolutely stable and $\lambda$ develops an ultraviolet Landau pole whose scale falls rapidly with increasing $k$: for moderate enhancement the pole lies near the Planck scale, while for the large enhancement $k\approx 7.2$ associated with radiative electroweak symmetry breaking the matching-scale coupling is $\lambda (M_t)\approx 0.9$ and perturbative validity is lost by $\sim 10^5$~GeV.

    hep-phhep-th0 citations
19. 19*

    Cosmological Limits on Strong Dark Forces

    Peter W. Graham🇺🇸 · Harikrishnan Ramani🇺🇸 · Olivier Simon🇺🇸 · Erwin H. Tanin🇺🇸

    We showcase cosmology's ability to constrain long-range forces between dark matter particles. Specifically, we consider a fermionic dark matter interacting via a Yukawa-coupled light scalar, focusing on regimes where the dark forces are stronger than gravitational and yet unconstrained. We show that the dark sector dynamics, both at the background and perturbation levels, is far richer than what can be captured with just the static interparticle Yukawa potential. The background dynamics includes an attractor that funnels a wide range of initial conditions onto an evolution unique to each parameter space. In a large swath of parameter space beyond existing limits, the dark sector deviates drastically from cold dark matter in observable epochs. We rule out this parameter space using existing constraints on dark-sector equation of state and small-scale cosmic perturbations, thus setting the strongest constraints yet on dark matter self-interactions at length scales shorter than 100 kpc. In addition, we briefly discuss repulsive dark forces and place cosmological limits that are stricter than in the attractive case.

    hep-phastro-ph.COgr-qc8 citations
20. 20*

    $L_{\mu }-L_{\tau }$ gauge bosons in beam dumps and supernovae

    Nikita Blinov🇨🇦 · Patrick J. Fox🇺🇸 · Kevin J. Kelly🇺🇸 · Ryan Plestid🇺🇸 · Tao Zhou🇺🇸

    We study the phenomenology of a sub-GeV $L_{\mu }-L_{\tau }$ gauge boson. We find discrepancies with existing literature in sensitivity projections for the upcoming SHiP experiment and in the treatment of supernovae cooling constraints. We present a quantitative analysis of different production modes in beam dumps and compare our results to previous work. In the context of supernovae, we re-evaluate the standard supernova cooling bounds from SN1987A and analyze additional supernova-based probes: diffusive cooling, constraints from the existence of low-energy supernovae, and the absence of a high-energy neutrino signal from SN1987A.

    hep-phastro-ph.HEhep-exJHEP(2026)·13 citations
21. 21*

    Ultralight Dark Matter from the Edge of Field Space

    Mathias Becker🇮🇹 · Francesco D'Eramo🇮🇹 · Ville Vaskonen🇪🇪

    We introduce a novel class of bosonic dark matter candidates that we dub wallions, featuring boundaries in field space. The wallion mass is exponentially suppressed when the separation between boundaries far exceeds their intrinsic width and remains radiatively stable under self-interactions. We study the early-universe evolution of wallions and the associated cosmological signatures. Finally, we show that instanton effects can dynamically generate field-space boundaries and discuss possible experimental probes once the wallion couples to Standard Model fields.

    hep-phastro-ph.COPRL(2026)·4 citations
22. 22*

    Entanglement, Yang-Mills, and the Scattering Matrix as an SU(N)-equivariant Kernel

    Kun-Feng Lyu🇺🇸 · Rahul Muraleedharan🇺🇸 · Kuver Sinha🇺🇸

    We study two-body scattering as an SU(N)-equivariant map acting on tensor-product representation spaces and analyze the entanglement generated by the $S$-matrix. This representation-theoretic perspective separates group structure from dynamics: the decomposition of $R\otimes R^{\prime }$ fixes the invariant operator algebra and therefore the qualitative entangling power of the process. For particles in the fundamental representation, ${\mathrm{End}}_{\mathrm{SU}(N)}(N\otimes N)=\mathrm{Span}\{\mathbb{I},\mathbb{S}\}$, so only the identity and swap directions preserve separability, whereas generic combinations generate entanglement. Adjoint-adjoint scattering involves a larger invariant algebra involving $d$-tensors and is intrinsically entangling. In Yang-Mills theory one can use color-kinematics duality to show that the color kernel lies on a fixed ray of this operator space, yielding a universal maximum of the outgoing entanglement for scattering at right angles, $E_{\star }^{(2)}=\frac{3}{4}$ for $SU(2)$ and $E_{\star }^{(3)}\simeq 0.91$, independent of kinematics. Dimension-six operators preserve this universality, while dimension-eight deformations populate new color sectors and shift $E_{\star }^{(N)}$, suggesting that entanglement in color space functions as a tomographic probe of effective operators. In helicity space, requiring maximally entangled inputs to scatter into maximally entangled outputs uniquely selects the Yang-Mills quartic coupling and enforces the color Jacobi identity, restating the on-shell Ward constraints as conditions on entanglement preservation. Our results suggest that the information-theoretic viewpoint unifies algebraic, geometric, and dynamical aspects of scattering.

    hep-phhep-thquant-phJHEP(2026)·3 citations
23. 23*

    A new approach to determine the thermodynamics of deconfined matter to high accuracy

    Tyler Gorda🇺🇸 · Pablo Navarrete🇫🇮 · Risto Paatelainen🇫🇮 · Leon Sandbote🇫🇮 · Kaapo Seppänen🇫🇮

    We demonstrate that at finite density and sufficiently high temperatures, phase-quenched (PQ) lattice simulations combined with perturbation theory provide a new precision approach to determining the thermodynamics of QCD across a wide arc of the phase diagram where the strong coupling constant ${\alpha }_s$ remains small. In this regime, nonperturbative pairing effects in the PQ theory are parametrically suppressed, so that the difference between the PQ and full QCD pressures becomes a small perturbative correction. We compute this correction up to and including $O({\alpha }_s^{7/2})$ using electrostatic QCD together with a novel numerical method to compute four-loop sum-integrals. This enables the determination of the perturbative QCD pressure with precision beyond the current state of the art while including nonperturbative pure-gluonic contributions from the lattice.

    hep-ph6 citations
24. 24*

    Freezing-in the Axiverse

    Christopher Dessert🇺🇸 · Soubhik Kumar🇺🇸 · Joshua T. Ruderman🇺🇸

    The presence of multiple light axions in the infrared is a generic feature of many ultraviolet (UV) scenarios. In many cases the number of axions $\mathcal{N}$ is $\mathcal{O}(10-100)$ or more. Even in the scenario where these axions interact very weakly with the Standard Model (SM), the presence of $\mathcal{N}$ light axions poses a challenge to the stringent constraint on the number of relativistic degrees of freedom $N_{\mathrm{eff}}$. In order to remain agnostic about the UV, we adopt an effective field theory (EFT) approach, and parametrize the interactions of $\mathcal{N}$ axions with the SM to quantify the contribution to $N_{\mathrm{eff}}$. We consider operators up to dimension six, uncovering one previously-unconsidered charge radius operator, and pay particular attention to the flavor structure of the axion-SM fermion couplings and consider EFTs based on anarchy, textures, and minimal flavor violation. For various choices of such EFTs, we identify the discovery space for current and future cosmic microwave background surveys, including the Simons Observatory and CMB-HD. We show this discovery space depends sensitively on the flavor structure and exhibits a rich interplay with terrestrial and astrophysical probes.

    hep-phastro-ph.COhep-th7 citations
25. 25*

    Octet scalars shaping LHC distributions in 4-jet final states

    Bogdan A. Dobrescu🇺🇸 · Max H. Fieg🇺🇸

    We study properties of a hypothetical scalar particle, $\Theta$, which is a color octet and an electroweak singlet. At hadron colliders, $\Theta$ is pair produced through its QCD coupling to gluons, so that its mass determines the cross section. It decays at tree level into $q\bar{q}$ through dimension-5 operators, and at one loop into gluons. Thus, the main LHC signature of $\Theta$ is a pair of dijets of equal invariant mass. The CMS search in this channel shows a $3.6\sigma$ excess over the QCD background for a dijet mass $M_{jj}\approx 0.95$ TeV, which can be due to $\Theta$: its production cross section (65 fb for a real scalar) and the acceptance of the CMS event selection applied to $pp\to \Theta \Theta \to (q\bar{q})(q\bar{q})$ yield a rate consistent with the excess. Furthermore, the shape of the $d\sigma /d{M}_{jj}$ signal is in agreement with the CMS result. Given the data-driven background fit performed by CMS, we find that a complex scalar fits better the data than a real scalar. Besides the pair of dijets, testable LHC signals include a trijet-dijet topology, a $t\bar{t}$ pair plus a dijet resonance, as well as final states involving a Higgs, $W$ or $Z$ boson plus jets.

    hep-phhep-exSciPost Phys.(2026)·2 citations
26. 26*

    Electromagnetic Radiation from Baryon-Rich Matter in Heavy-Ion Collisions

    Xiang-Yu Wu🇨🇦 · Charles Gale🇨🇦 · Sangyong Jeon🇨🇦 · Jean-François Paquet🇺🇸 · Björn Schenke🇺🇸 · Chun Shen🇺🇸

    We perform a study of electromagnetic radiation in heavy-ion collisions at Relativistic Heavy Ion Collider (RHIC) Beam Energy Scan (BES) and SPS energies using the iEBE-MUSIC framework, which includes 3D dynamical Monte Carlo Glauber initial conditions, MUSIC (3+1)D viscous relativistic hydrodynamics, and the UrQMD hadronic afterburner. The multistage modeling has been calibrated to hadronic data at RHIC-BES energies using a Bayesian analysis. Integrating the thermal photon emission rates with the medium evolution, we study the direct photon yield and elliptic flow and how they vary with collision energy and emission source. We compare with results obtained by the STAR and PHENIX Collaborations. We employ next-to-leading order thermal QCD dilepton emission rates to compute dilepton invariant mass spectra and extract the effective temperature of the quark-gluon plasma at different collision energies.

    ↳ nucl-thhep-phnucl-ex3 citations
27. 27*

    Learning to Validate Generative Models: a Goodness-of-Fit Approach

    Pietro Cappelli🇮🇹 · Gaia Grosso🇺🇸 · Marco Letizia🇮🇹 · Humberto Reyes-González🇩🇪 · Marco Zanetti🇮🇹

    Generative models are increasingly central to scientific workflows, yet their systematic use and interpretation require a proper understanding of their limitations through rigorous validation. Classic approaches struggle with scalability, statistical power, or interpretability when applied to high-dimensional data, making it difficult to certify the reliability of these models in realistic, high-dimensional scientific settings. Here, we propose the use of the New Physics Learning Machine (NPLM), a learning-based approach to goodness-of-fit testing inspired by the Neyman--Pearson construction, to test generative networks trained on high-dimensional scientific data. We demonstrate the performance of NPLM for validation in two benchmark cases: generative models trained on mixtures of Gaussian models with increasing dimensionality, and a public end-to-end model, known as FlowSim, developed to generate high-energy physics collision events. We demonstrate that the NPLM can serve as a powerful validation method while also providing a means to diagnose sub-optimally modeled regions of the data.

    ↳ stat.MLcs.LGhep-exhep-phMach.Learn.Sci.Tech.(2026)·7 citations
28. 28*

    Explaining higher-order correlations between elliptic and triangular flow

    Mubarak Alqahtani🇸🇦 · Jean-Yves Ollitrault🇫🇷

    The ALICE and CMS Collaborations have analyzed a number of cumulants mixing elliptic flow ($v_2$) and triangular flow ($v_3$), involving up to $8$ particles, in Pb+Pb collisions at the LHC. We unravel an unexpected simplicity in these complex mathematical quantities for collisions at fixed impact parameter. We show that as one increases the order in $v_2$, for a given order in $v_3$, the changes in the cumulants are solely determined by the mean elliptic flow in the reaction plane, which originates from the almond-shaped geometry of the overlap area between the colliding nuclei. We derive simple analytic relations between cumulants of different orders on this basis. These relations are in good agreement with recent data from the CMS Collaboration. We argue that agreement will be further improved if the analysis is repeated with a finer centrality binning. We make quantitative predictions for cumulants of order 10 which have not yet been analyzed.

    ↳ nucl-thhep-exhep-phnucl-exPLB(2026)·1 citation
29. 29*

    Gauged Soft Recursion: On-Shell Construction of Goldstone-Gauge Amplitudes

    Ian Low🇺🇸 · Ming-Lei Xiao🇨🇳 · Yu-Hui Zheng🇰🇷

    We present a new on-shell recursion relation for scattering amplitudes involving Nambu-Goldstone bosons with a gauged unbroken symmetry. A central challenge is that gauge interactions break Adler's zero condition for charged scalars, invalidating the standard soft recursion. To overcome this, we introduce a ``gauged soft recursion'' that leverages the soft theorems of the gauge bosons themselves, combined with a novel decomposition of amplitudes into gauge-invariant components where Adler's zero is partially restored. The formalism, which also incorporates internal gauge bosons via angular momentum constraints, enables the systematic construction of tree-level amplitudes with arbitrary numbers of Goldstone bosons and gauge bosons in both Abelian and non-Abelian theories, as we demonstrate with explicit examples.

    ↳ hep-thhep-phnucl-thJHEP(2026)·1 citation
30. 30*

    Fermi-Dirac Wigner function for massive spin-1/2 particles in local equilibrium

    Sudip Kumar Kar🇵🇱 · Valeriya Mykhaylova🇵🇱

    A recently proposed Boltzmann local equilibrium Wigner function for massive spin-1/2 particles is generalized to the case of Fermi-Dirac statistics. The resulting formula ensures the correct normalization of the mean polarization vector and reproduces the generalized thermodynamic relations with spin that were obtained in earlier studies. Moreover, we show that the macroscopic currents constructed from the Fermi-Dirac Wigner function can be obtained as derivatives of a suitably defined generating function with respect to the Lagrange multipliers (temperature, hydrodynamic flow, and chemical potentials). The identified generating function also indicates that the underlying framework can be classified as a divergence-type theory.

    ↳ quant-phhep-phnucl-th5 citations
31. 31*

    Dark Photons in the Radio Sky: I. Resonant Conversions in Halos

    Ethan Baker🇺🇸 · Hongwan Liu🇺🇸

    Mixing between dark photons and visible photons leads to substantial anisotropies in the cosmic microwave background due to resonant conversions of visible photons into dark photons in baryonic matter found in dark matter halos. In this Letter, we forecast the sensitivity of the Square Kilometre Array (SKA) to this signal. We find that SKA could be the first experiment to discover dark photons with a mass between $10^{-13}$ and $5\times 10^{-12}$ eV and kinetic mixing parameter $ϵ$ as small as $\sim 10^{-8}$ by cross-correlating their data with a low-redshift galaxy survey, potentially improving on the sensitivity from a similar analysis using Planck data by a factor of 4 in $ϵ$. This improvement is largely due to an enhancement of the signal at low frequencies and the unique experimental advantages of radio telescopes such as small beam sizes.

    ↳ astro-ph.COhep-phPRD(2026)·1 citation
32. 32*

    Dark Photons in the Radio Sky: II. Resonant Conversions in the Intergalactic Medium

    Ethan Baker🇺🇸 · Hongwan Liu🇺🇸

    This is the second part in a pair of papers forecasting the sensitivity of the Square Kilometre Array (SKA) to dark photons, a highly motivated, simple extension of the Standard Model. Through a kinetic mixing term, visible photons from the cosmic microwave background can resonantly convert into dark photons, generating new temperature anisotropies in the sky. In this work, we detail the entire analysis pipeline that we use to compute SKA's sensitivity, focusing on resonant conversions that occur in the intergalactic medium. We also discuss the sensitivity of 21-cm experiments to dark photons. Our results show that both SKA in combination with galaxy surveys and 21-cm experiments could discover dark photons with masses between $5\times 10^{-15}$ and $5\times 10^{-12}$ eV, and kinetic mixing parameter $ϵ$ as low as $10^{-8}$.

    ↳ astro-ph.COhep-phPRD(2026)·1 citation

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.