Thu·Mar 5, 2026Thursday·March 5, 2026

1. 01*

   New Thermal-Relic Targets for sub-GeV Dark Matter Direct Detection

   Xu Han🇺🇸 · Gordan Krnjaic🇺🇸

   Dark matter direct detection experiments involving electron recoils are beginning to test highly-predictive, thermal-relic milestones for sub-GeV dark matter models. Due to the Lee-Weinberg bound, thermal dark matter candidates in this mass range necessarily require comparably-light mediator particles to achieve a suitably large annihilation cross section. Here we present new thermal-relic milestones for sub-GeV dark matter candidates that couple to vector mediators. In these models, the mediators are massive gauge bosons of anomaly-free abelian extensions to the Standard Model, including the dark photon, gauged $L_i-L_j,B-L$, and $B-3L_i$ models, where $B$ is the baryon number, $L$ is the lepton number, and $i,j$ index the lepton families. Since the same interactions that govern cosmological production also govern electron scattering, the targets we present are firmly predictive and allow for these models to be robustly discovered or falsified. Furthermore, since the mediators we study exhaust the minimal anomaly-free U(1) extensions to the Standard Model, our results offer a complete list of predictive milestones for sub-GeV dark matter coupled to vector mediators.

   hep-phastro-ph.COPRD(2026)·2 citations
2. 02*

   Emergent axion and Higgs boson from strong dynamics

   Florian Goertz🇩🇪 · Andrea Incrocci🇩🇪

   We propose a unified model that simultaneously addresses the hierarchy problem and the strong CP problem by considering the most simple fundamental composite Higgs setup and showing that it can feature a viable emergent axion that could be accessible at collider experiments. To maintain a low decay constant, and therefore address the hierarchy problem, while simultaneously avoiding experimental bounds on the axion couplings, we increase the axion mass via additional small instanton contributions coming from a new hidden gauge sector with a confinement scale larger than ${\Lambda }_{\text{QCD}}$. Specifically, the axion will be identified with the CP-odd scalar singlet contained in the $SU(4)/Sp(4)$ coset of the minimal fundamental composite Higgs model. Both the SM color group and the additional hidden sector group are then embedded into a larger non-Abelian \textit{grandcolor} group, such that the topological angles of the two sectors are guaranteed to agree at tree-level. Beyond that, we show that radiative corrections and other CP-violating sources can be controlled. After examining the field content and the gauge structure of the model, we analyze the pNGB spectrum, potential, and couplings, as well as the resulting phenomenology. We focus in particular on the axion potential, to understand under which conditions the CP-odd scalar singlet can solve the strong CP problem while maintaining a naturally low compositeness scale, identifying interesting viable parameter space for an axion in the GeV range.

   hep-ph0 citations
3. 03*

   Flavor in Ninths and a Discrete Gauge Origin of the QCD Axion

   Vernon Barger🇺🇸

   Quark and lepton hierarchies are organized by rational powers of a single parameter (the quark masses and mixings in ninths, the charged-lepton mass ratios in sixths). We argue that this structure points to a discrete ${\mathbb{Z}}_{18}$ origin of Froggatt--Nielsen symmetry, fixed as the least common denominator $\mathrm{lcm}(9,6)=18$, with its ${\mathbb{Z}}_9$ subgroup governing the quark lattice and the full ${\mathbb{Z}}_{18}\cong {\mathbb{Z}}_9\times {\mathbb{Z}}_2$ required to accommodate the half-integer lepton charges. The flavon is the unique ${\mathbb{Z}}_{18}$-charged scalar with a large VEV, so its phase is the Peccei--Quinn axion; the \emph{same} symmetry then solves the strong $CP$ problem and forbids every Planck-suppressed PQ-violating operator below dimension eighteen. Our central result is that, because the order of ${\mathbb{Z}}_{18}$ is fixed by the flavor data rather than chosen to protect the axion, the resulting high axion quality (the residual shift of the axion vacuum from $\bar{\theta }=0$ being only $|\Delta \bar{\theta }|\lesssim 3\times 10^{-27}$) is a prediction of the flavor structure rather than an imposed ingredient. The axion is a generation-dependent Type-II DFSZ axion with domain-wall number $N_{\mathrm{DW}}=6$. The decisive phenomenological consequence is that the same non-universal charges that reproduce the fermion masses enhance the axion--photon coupling to an observable level, $C_{a\gamma }\simeq 0.6$--$1.0$ (well above the higgsino-suppressed MSSM value), placing the dark-matter axion at $m_a\simeq 7$--$12\mu$eV within reach of upcoming haloscope searches.

   hep-phhep-ex3 citations
4. 04*

   Searching for ALP Lepton Flavor Violation via ALP Decays at the LHC

   Xiaochu Zheng🇨🇳 · Ruitian Li🇨🇳 · Jing Li🇨🇳 · Hao Sun🇨🇳

   In the ALP model, lepton flavor violation (LFV) can arise from off-diagonal ALP-lepton couplings ($g_{a{\ell }_i{\ell }_j}$), which are absent in the Standard Model. We focus on ALP production via gluon fusion ($pp\to a$) at the Large Hadron Collider (LHC), which dominates the ALP mass range of 5-1000 GeV due to its high cross section and manageable backgrounds. We are interested in the decay of an axion into an electron and a muon, two oppositely charged leptons of different flavors. After background suppression, we obtain the sensitivity to ALP in this mass range, finding significantly improved limits for $5<m_a<1000$ GeV, where SM backgrounds are suppressed. Our research is complementary with relevant studies.

   hep-ph0 citations
5. 05*

   Method of regions for dual conformal integrals

   Roman N. Lee🇷🇺

   In this contribution, we present a recently introduced approach [BorkLeeOnishchenko2025] to the calculation of slightly off-shell dual conformal integrals based on the method of regions with regularization preserving dual conformal invariance (DCI). Unlike conventional dimensional regularization, which breaks DCI, our approach uses a combination of dimensional and analytic regularizations specifically designed to retain DCI throughout the calculation. Our approach drastically simplifies the computation of slightly off-shell dual conformal integrals. For the two-loop five-point DCI integrals we find that with DCI-preserving regularization, the contributions of all regions can be expressed in terms of $\Gamma$-functions, resulting in a remarkably compact final expression in terms of logarithms of cross-ratios only. This is in sharp contrast to conventional approach which yields complex polylogarithmic expressions [Belitsky&Smirnov2025]. We argue that a similar approach might be useful also for non-DCI integrals.

   hep-ph0 citations
6. 06*

   Inverse Excitation Hierarchy in Doubly-Heavy Tetraquarks within the Diquark Model

   Maximilian Weber🇯🇵 · Daiki Suenaga🇯🇵 · Masayasu Harada🇯🇵

   We investigate the $T_{cc}$ tetraquark, treating it as a bound state of a heavy diquark and a light antidiquark. Using the Silvestre-Brac potential and solving the Schrödinger equation via the Gaussian Expansion Method, we find that the excitation energy between the heavy diquark and light antidiquark is unexpectedly larger than that between the two light anti-quarks within the anti-diquark -- contrary to the naive expectation where the former is smaller than the latter. We trace this inversion of the mass hierarchy to the centrifugal force acting on the light degree of freedom. Applying the same framework to other systems ($T_{bb},{\Lambda }_b,{\Lambda }_c$) yields qualitatively identical behavior, demonstrating the robustness of the mechanism. These results provide new insights into diquark dynamics and the mass structure of exotic hadrons.

   hep-phnucl-thPRD(2026)·0 citations
7. 07*

   Leptogenesis from the Dirac CP-violating phase in the minimal left-right symmetric model

   Xueke Chen🇨🇳 · Xinyi Zhang🇨🇳

   Leptogenesis from low-energy CP violation provides a vital link between neutrino physics and the observed baryon asymmetry of the universe. However, this connection is typically obscured by unknown high-energy parameters. In this work, we investigate thermal leptogenesis in the Minimal Left-Right Symmetric Model with generalized parity as the left-right symmetry, where the hermiticity of the Dirac neutrino coupling allows the right-handed mixing matrix $V_{\mathrm{R}}$ to be determined with minimal assumptions. We show that for a real $V_{\mathrm{R}}$, these conditions favor CP-conserving Majorana phases, leaving the Dirac CP-violating phase ($\delta$) as the sole source of asymmetry. By numerically exploring all four leptogenesis scenarios, we demonstrate that $\delta$ alone can generate the observed baryon asymmetry with the correct sign within specific regions of the parameter space. The results exhibit a high sensitivity to the neutrino mass ordering and the lightest neutrino mass, providing a stringent, testable framework for future experimental measurements of the CP phase and neutrino mass scale.

   hep-phNPB(2026)·3 citations
8. 08*

   Interpretation of $\Omega (2012)$ as a $\Xi (1530)K$ molecular state

   Xiang Yu🇨🇳 · Jin-Peng Zhang🇨🇳 · Xu-Liang Chen🇨🇳 · Ding-Kun Lian🇨🇳 · Qi-Nan Wang🇨🇳 · Wei Chen🇨🇳

   We investigate the mass and strong decay properties of the $\Omega (2012)$ resonance using QCD sum rules, assuming it to be an S-wave $\Xi (1530)\bar{K}$ molecular pentaquark state with $I(J^P)=0({\frac{3}{2}}^{-})$. A unified interpolating current is constructed, and the two-point correlation functions and three-point functions are calculated up to dimension-13 and 10 condensate terms in the OPE series, respectively. The negative-parity contribution is isolated by employing parity-projected sum rules. The two-body strong decays to ${\Xi }^0{K}^{-}$ and ${\Xi }^{-}{\bar{K}}^0$ are studied via their three-point correlation functions. Our analysis yields a mass of $2.00\pm 0.15\mathrm{GeV}$ and a total two-body decay width of $\Gamma =0.96_{-0.41}^{+0.79}\mathrm{MeV}$ for the $\Xi (1530)\bar{K}$ molecular state. The ratio of the two-body decay branching fractions is obtained as ${\mathcal{R}}_{{\Xi }^0{K}^{-}}^{{\Xi }^{-}{\bar{K}}^0}=0.85$. These results are compatible with the experimental data for the $\Omega (2012)$ within uncertainties and support its interpretation as a $\Xi (1530)\bar{K}$ molecular pentaquark state.

   hep-phhep-exhep-latCPC(2026)·0 citations
9. 09*

   Weak Interaction Contribution to the Muonium Hyperfine Structure in the Standard Model

   F. A. Martynenko🇷🇺 · A. P. Martynenko🇷🇺 · K. A. Seredina🇷🇺

   The contribution of the weak interaction to the hyperfine splitting of the ground state of muonium is investigated. The amplitudes of the one- and two-quantum exchange determined by the Z and W bosons are calculated. One-loop corrections in the photon and Z boson propagators and their contribution to the hyperfine structure of the spectrum are obtained.

   hep-phPRA(2026)·0 citations
10. 10*

    NNLO DGLAP splitting functions from collinear matching of TMDs

    Yu Jiao Zhu🇩🇪

    We report a complete computation of next-to-next-to-leading order (NNLO) helicity and transversity Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) splitting functions, in both space-like and time-like kinematics. These results are obtained from the next-to-next-to-next-to-leading order (N${}^3$LO) twist-2 matching of polarized transverse-momentum-dependent (TMD) parton distribution and fragmentation functions, including helicity, quark transversity, and linearly polarized gluons. We compare our results with existing calculations in the literature and discuss both agreements and discrepancies. Our results provide all perturbative ingredients required for the computation of N${}^3$LO differential cross sections below the resolution scale $q_{T\mathrm{cut}}$ in transverse-momentum subtraction and enable next-to-next-to-next-to-next-to-leading logarithmic (N${}^4$LL) resummation of $q_T$ observables in the Sudakov region. We further determine the small-$x$ structure of the polarized matching coefficients through N${}^3$LO. These fixed-order results furnish the data for future small-$x$ resummation in polarized TMD factorization, where high-energy logarithms and Sudakov logarithms become simultaneously relevant. Establishing a consistent joint treatment of polarized small-$x$ evolution and transverse-momentum resummation remains an important open direction toward uniform precision in spin-dependent phenomenology. Our results provide essential theoretical input for precision spin physics at the forthcoming Electron-Ion Collider.

    hep-ph0 citations
11. 11*

    Features of Spacetime-Symmetry Breaking and the Standard-Model Extension in Riemann-Cartan Geometry

    Robert Bluhm🇺🇸

    For over two decades, the gravity sector of the Standard-Model Extension (SME) has served as a phenomenological framework for testing spacetime symmetry breaking in the presence of gravity. During this time, various theoretical features have been examined in greater detail and some refinements have been made. In particular, differences between spontaneous and explicit breaking of diffeomorphisms, local translations, and local Lorentz transformations in Riemann-Cartan geometry, as well as their corresponding consistency issues with geometric and mathematical identities, have been probed more deeply. This has led to a modified version of the SME being developed that is suitable for investigating explicit breaking in gravity theories, which can be used as well to search for new geometries that go beyond Riemann-Cartan. A selective overview of some of these features is presented here.

    hep-ph0 citations
12. 12*

    Topological observables and domain wall tension from finite temperature chiral perturbation theory

    Zhen-Yan Lu🇨🇳 · Quan Tang🇨🇳 · Shu-Peng Wang🇨🇳 · Yang Huang🇨🇳 · Zhen Zhang🇨🇳 · Bonan Zhang🇨🇳

    Within the framework of SU(2) chiral perturbation theory, we derive the general solution of the QCD $\theta$-vacuum for an arbitrary vacuum phase, explicitly incorporating isospin-breaking effects from the light quark mass difference, and compute the temperature dependence of the topological susceptibility, higher-order cumulants, and the domain wall tension up to next-to-leading order. We find that the topological susceptibility agrees with lattice data at low temperatures but deviates at higher temperatures as expected from the breakdown of the chiral expansion; moreover, we demonstrate that the normalized fourth-order cumulant and the domain wall tension decrease monotonically with increasing temperature, while the normalized sixth-order cumulant exhibits the opposite behavior. These results extend earlier analyses by showing how isospin breaking reshapes the full hierarchy of topological charge cumulants and the dynamics of $\theta$-vacuum domain walls, thereby offering new theoretical input on the $\theta$-vacuum properties, which are relevant for axion-related effective theories in hot QCD matter.

    hep-phhep-lathep-thnucl-thPRD(2026)·2 citations
13. 13*

    Dark matters are Inert, or FIMPy, or WIMPy or UFOy: An inflationary gravitational particle production

    Ayan Chakraborty🇮🇳 · Debaprasad Maity🇮🇳 · Rajesh Mondal🇮🇳

    In this letter, we explore the phenomenological impact of inflationary gravitational particle production in the physics of Dark Matter (DM). Large-scale DM fluctuations generated during inflation behave as gravitational particles upon their post-inflationary horizon reentry and alter the conventional Boltzmann dynamics of DM with a non-conserving source term, thereby producing significant phenomenological consequences. Within this framework, we analyze four distinct types of DM classified according to their production mechanisms. Dark matter may be completely non-interacting with the thermal bath, behaving as Inert Dark Matter. Alternatively, depending on the strength of its interactions with bath particles, DM may exhibit WIMPy, UFOy, or FIMPy behavior, sharing characteristics with their conventional counterparts. The late-time enhancement of the DM number density, driven by the successive horizon reentry of gravitationally produced low-momentum modes, enlarges the viable parameter space for both thermal and non-thermal DM scenarios. Remarkably, this expanded parameter space remains consistent with current constraints from $\Delta N_{\mathrm{eff}}$ and Lyman-$\alpha$ bound.

    hep-phastro-ph.COhep-th2 citations
14. 14*

    Nuclear $\mu -e$ conversion via Lorentz and CPT violation

    William P. McNulty🇺🇸

    One of the three common experimental channels searching for charged lepton flavor violation (CLFV) via $\mu -e$ conversion involves first capturing the muon on a nuclear target. This channel provides a unique opportunity to constrain four-point quark-lepton operators that may contribute to CLFV, in addition to the electromagnetic operators that can also be accessed in the other channels. We investigate the leading Lorentz- and CPT-violating contributions for nuclear $\mu -e$ conversion experiments within the Standard-Model Extension and obtain the first bounds on the relevant quark-lepton operators using the results of the SINDRUM II experiment; we also consider possibilities for improved constraints from upcoming experiments.

    hep-ph0 citations
15. 15*

    A baryon-calibrated unified quark-diquark effective mass formalism for heavy multiquarks

    Binesh Mohan🇮🇳 · Rohit Dhir🇮🇳

    We present a unified framework for heavy tetraquark and pentaquark systems within the quark-diquark effective mass formalism, extending its baryon-calibrated construction to multiquark states without introducing sector-dependent parameters. Intra-diquark color-spin correlations are encoded in effective diquark masses fixed from baryon spectroscopy, while the inter-cluster chromomagnetic scale, independently determined from vector-pseudoscalar meson splittings, is propagated unchanged to exotic configurations, ensuring residual one-gluon exchange dynamics only between composite color sources. Within this framework, we compute the complete spectra for both ${\bar{3}}_c\otimes 3_c$ and $6_c\otimes {\bar{6}}_c$ configurations in tetraquarks, whereas the pentaquark analysis focuses on the dominant ${\bar{3}}_c\otimes {\bar{3}}_c\otimes {\bar{3}}_c$ clustering. Heavy-quark spin symmetry and flavor-symmetry breaking across light, charm, and bottom sectors emerge naturally through the explicit $1/(m_{D_1}{m}_{D_2})$ scaling of the calibrated couplings. The resulting spectra exhibit a coherent dynamical hierarchy spanning baryons and multiquark states. Established exotic candidates are reproduced within hadronic uncertainties, while the unified calibration enables quantitative predictive control across flavor sectors. The framework thus provides a parameter-economical, systematically constrained baseline with unified dynamical consistency for heavy multiquark spectroscopy.

    hep-phhep-ex4 citations
16. 16*

    Quantum Kinetic Theory for Quantum Chromodynamics

    Shu Lin🇨🇳

    We develop a quantum kinetic theory for QCD, which incorporates all leading order collision terms. At lowest order in gradient expansion, it reproduces the spin-averaged Boltzmann equation with both elastic and inelastic collisions. At next order in gradient expansion, the solution to the quantum kinetic equations give spin polarization of on-shell quarks and gluons in quark-gluon plasma when the gradients are of hydrodynamic ones. A power counting in the coupling shows the spin polarization behaves differently in vortical and non-vortical gradients: the former is free of collisional contribution to leading order, while the latter contains a collisional contribution at parametrically the same order as the free theory counterpart. We also find the inelastic collision in a spin basis provides a possible mechanism for conversion between spin and orbital angular momentum.

    hep-phnucl-th1 citation
17. 17*

    A framework for missing-energy searches with anomalous light vectors

    Luca Di Luzio🇮🇹 · Marco Nardecchia🇮🇹 · Stefano Scacco🇮🇹 · Claudio Toni🇫🇷

    We study light spin-1 gauge bosons coupled to electroweak-anomalous currents. For generic charge assignments, anomaly cancellation requires new fermions (anomalons) that are chiral under the new abelian symmetry and carry electroweak charges. If their masses arise from the breaking of the new gauge symmetry, integrating them out generates Wess-Zumino interactions fixed by mixed-anomaly matching, providing the infrared description of the theory. We classify minimal anomalon spectra, derive the corresponding effective interactions, and combine experimental constraints with finite-naturalness considerations to bound the UV completion scale. Motivated by recent NA62 and Belle II results, we then develop a unified phenomenological framework for the missing-energy signatures of these anomalous light vectors, focusing on scenarios where the new vector decays predominantly into neutrinos so that the leading probes are rare processes with invisible final states. As applications, we survey current and projected searches across flavour and electroweak observables, including $K\to \pi E_{\mathrm{miss}}$, $B\to K^{(\ast )}{E}_{\mathrm{miss}}$, and $Z\to \gamma E_{\mathrm{miss}}$, and discuss their interplay with direct searches for anomalons.

    hep-phJHEP(2026)·1 citation
18. 18*

    Covariant canonical-spinor amplitudes for partial wave analysis

    Hong Huang🇨🇳 · Yi-Ning Wang🇨🇳 · Jiang-Hao Yu🇨🇳

    We propose a covariant orbital-spin ($LS$) decomposed amplitude for the partial wave analysis using the massive spinor-helicity formalism. First we review the traditional-$LS$ method in the little group space and the Zemach tensor method in the double cover of the $\mathrm{SO}(3)$ space. To recover the $\mathrm{SO}(3,1)$ Lorentz covariance, several Lorentz covariant $LS$ tensors have been constructed in several different methods: covariant tensor, covariant projection tensor in pure-spin and general-spin schemes, but performing a intrinsic separation between $LS$ coupling while maintaining covariance is not obvious. We utilize the massive canonical-spinor variables to determine general three-point amplitudes, in which the spin-orbital decomposition is realized in single little group space by projecting little group indices of each particles into one, while the Lorentz covariance is ensured by the spinor form naturally. This covariant spinor method allows direct evaluation in any frame and a streamlined treatment of cascade decays within a single frame without additional alignment rotations in non-covariant treatment. As a benchmark, we implement the method in TF-PWA and analyze ${\Lambda }_c^{+}\to \Lambda {\pi }^{+}{\pi }^0$, finding consistent fit results across the helicity, traditional-$LS$, and canonical-spinor amplitudes. This validates the canonical-spinor amplitude as a practical tool for modern partial wave analyses of complex decay chains.

    hep-phhep-exhep-th2 citations
19. 19*

    Domain Walls from $\Sigma (36\times 3)$, $\Delta (54)$ and $\Delta (27)$ potentials

    Gonçalo Barreto🇵🇹 · Ivo de Medeiros Varzielas🇵🇹 · Ye-Ling Zhou🇨🇳

    We consider the degenerate minima arising from scalar potentials invariant under $\Sigma (36\times 3)$, or under its subgroups $\Delta (54)$ and $\Delta (27)$ (with or without imposed CP symmetries), for a triplet of those symmetries. In this framework, we classify the distinct Domain Walls between the degenerate minima and calculate the respective tensions.

    hep-phPRD(2026)·4 citations
20. 20*

    Momentum fraction and hard scale dependence of double parton scattering in heavy-ion collisions

    Joao Vitor C. Lovato🇧🇷 · Edgar Huayra🇧🇷 · Emmanuel G. de Oliveira🇧🇷

    In a previous work, we studied the momentum fraction and hard--scale dependence of double parton scattering (DPS) in proton--proton collisions and the resulting dependence of the effective cross section on the final--state observables. In this paper, we extend those results to heavy--ion ($pA$ and $AA$) collisions, accounting for nuclear effects in the relevant kinematic region, namely shadowing and antishadowing. In addition to modifying the longitudinal parton distributions, these effects also alter the transverse parton distribution of the nucleus, for which we propose a simple new nuclear profile. We further hypothesize that partons inside a bound nucleon are more widely separated than in a free proton. We compute the effective cross section for the available $p$Pb data, obtaining reasonable agreement, and provide predictions for future measurements at the LHC. The observed dependence of our predictions on the final state indicates that DPS in heavy--ion collisions can be used to probe the transverse profile of the free proton and the bound nucleon, primarily in $pA$ collisions, as well as the transverse structure of the nucleus, mainly in $AA$ collisions.

    hep-ph0 citations
21. 21*

    Illuminating the dark universe in the multi-messenger era

    Philippe Brax🇫🇷 · Anne-Christine Davis🇬🇧 · Md Riajul Haque🇨🇳 · Cédric Jockel🇩🇪 · Gaetano Lambiase🇮🇹 · Michiru Uwabo-Niibo🇰🇷 · Mohsen Khodadi🇮🇷 · Tanmay Kumar Poddar🇬🇧 · Laura Sagunski🇩🇪 · Luca Visinelli🇮🇹 · Jun Zhang🇨🇳

    The precision era of multi-messenger astronomy, together with modern astrophysical, cosmological, and gravitational wave observations, increasingly points toward the existence of a ``dark" sector that cannot be explained within the framework of the Standard Model of particle physics and General Relativity. In this review, we explore extensions of standard physics and examine how observational data can be used to probe new particles and interactions. We consider a wide range of scales, from Solar System tests to galactic and cosmological observations, and investigate both conventional dark matter candidates, such as weakly interacting massive particles, and alternative scenarios including ultralight fields and primordial black holes. We discuss constraints derived from compact objects such as neutron stars, black holes, pulsars, and magnetars observations as well as from high-energy astrophysical phenomena. In addition, we analyze extensions of General Relativity involving additional scalar fields and their impact on gravitational wave signals and stochastic backgrounds from primordial black holes. We also study the capture and accumulation of dark matter in compact objects, which can alter properties such as mass, radius, and tidal deformability, and consider scenarios in which dark matter decays into Standard Model particles. While current observations already place significant limits on dark matter and modified-gravity models, upcoming experiments and observatories are expected to further probe or discover such new physics by improving constraints on particle masses and interaction strengths.

    ↳ astro-ph.COgr-qchep-ph5 citations
22. 22*

    Observational constraints on Luciano-Saridakis entropic cosmology

    Matías Leizerovich🇦🇷 · Susana J. Landau🇦🇷 · Giuseppe Gaetano Luciano🇪🇸 · Andreas Papatriantafyllou🇬🇷 · Emmanuel N. Saridakis🇬🇷

    A recently proposed generalized entropy by Luciano and Saridakis extends the standard Boltzmann-Gibbs and Bekenstein-Hawking framework through a microscopically motivated construction involving two independent entropic exponents. When applied within the gravity-thermodynamics correspondence, this entropy leads to a modified cosmological dynamics that can be interpreted as an effective dark energy sector of entropic origin, while recovering $\Lambda$CDM in appropriate limits. In this work, we perform the first observational confrontation of the resulting entropic cosmology at the background level. Focusing on the case ${\alpha }_{\delta }=0$, we constrain the model using Cosmic Chronometers, Pantheon${}^{+}$ Type Ia supernovae calibrated with SH0ES, BAO measurements from DESI DR2 and compressed Planck 2018 CMB information. We find that the model yields a statistically robust fit to the combined data sets and can simultaneously satisfy Pantheon${}^{+}$, SH0ES and CMB shift-parameter constraints, unlike $\Lambda$CDM. Although the entropic parameters remain close to their standard values, the $\Lambda$CDM limit is excluded at the $2\sigma$ level within the restricted parameter space considered. These results indicate that the Luciano-Saridakis entropic cosmology offers a viable extension of the standard model with the potential to alleviate the Hubble tension at the background level.

    ↳ astro-ph.COgr-qchep-exhep-ph+1Phys.Dark Univ.(2026)·7 citations
23. 23*

    An algorithm towards $\epsilon$-factorising Feynman Integrals

    epsilon-collaboration: Iris Bree🇩🇪 · Federico Gasparotto🇩🇪 · Antonela Matijašić🇩🇪 · Pouria Mazloumi🇩🇪 · Dmytro Melnichenko🇩🇪 · Sebastian Pögel🇨🇭 · Toni Teschke🇩🇪 · Xing Wang🇨🇳 · Stefan Weinzierl🇩🇪 · Konglong Wu🇨🇳 · Xiaofeng Xu🇨🇳

    In this talk, we use several examples to elaborate on how a recently proposed algorithm can turn non-trivial Feynman integrals into an $\epsilon$-factorised manner, regardless of their hidden geometric essence. In particular, some extra details about three-loop banana integrals with unequal-mass configuration are provided.

    ↳ hep-thhep-ph1 citation
24. 24*

    Imaging baryon number density within the proton

    Spencer R. Klein🇺🇸 · Mathias C. Labonte🇺🇸 · Zachary Sweger🇺🇸 · Gerald A. Miller🇺🇸 · Ramona Vogt🇺🇸

    The spatial extent of the proton is a key factor in nuclear physics. Different measurement techniques probe different aspects of the proton, yielding different radii. The mass and charge radii depend on the parton and quark distributions respectively, while the mechanical radius depends on the mass/energy distribution. Here, we probe the spatial distribution of a new proton characteristic, studying the distribution of baryon number within the proton. We investigate the baryon number distribution by studying four exclusive meson production channels arising from photon-proton collisions ($\gamma p\to p{\rho }^0$, $\gamma p\to p\omega$, $\gamma p\to n{\pi }^{+}$, and $\gamma p\to p{\pi }^0$). The two-dimensional transverse sizes of the interacting systems are extracted by analyzing the transverse momentum, $p_T$, dependence of the meson production cross section, using Fourier-Bessel transformations. We find that baryon number is confined to a transverse radius of $0.33-0.53$~fm. In comparison, the transverse radius of the proton charge and mass distributions are considerably larger, at least 0.67~fm. The baryon number is concentrated in the center of the proton.

    ↳ hep-exhep-phnucl-ex0 citations
25. 25*

    CFT Perspective On de-Sitter Cosmological Correlators

    Sayantan Choudhury🇮🇳

    We investigate the principles of quantum field theory using a stiff de Sitter space. We demonstrate that a non-unitary Lagrangian on a Euclidean AdS geometry can produce the perturbative expansion of late-time correlation functions to all orders. This discovery greatly simplifies perturbative computations while also allowing us to prove fundamental features of these correlators, which are part of a Euclidean CFT. This allows us to construct an OPE expansion, limit the operator spectrum, and deduce the analytic structure of the spectral density that captures the conformal partial wave expansion of a late-time four-point function. In general, the standard CFT concept of unitarity does not apply to dimensions and OPE coefficients. Rather, the positivity of the spectral density represents the unitarity of the de Sitter theory. This assertion is non-perturbative and does not depend on the use of Euclidean AdS Lagrangians. In a scalar theory, we compute tree-level and entire one-loop-resummed exchange diagrams to demonstrate and verify these characteristics. In the spectrum density, an exchanged particle shows up as a resonant characteristic that may be helpful in experimental searches.

    ↳ hep-thastro-ph.COgr-qchep-ph0 citations
26. 26*

    Lattice extraction of the Collins-Soper kernel using the auxiliary field representation of the Wilson line

    Anthony Francis🇹🇼 · C.-J. David Lin🇹🇼 · Wayne Morris🇹🇼 · Yong Zhao🇺🇸

    The Collins-Soper (CS) kernel may be obtained through the TMD soft function by formulating the Wilson line in terms of 1-dimensional auxiliary fermion fields on the lattice. Our computation takes place in the region of the lattice that corresponds to the "spacelike" region in Minkowski space, i.e., Collins' scheme. We explore two methods for obtaining the CS kernel. The "ratio method"; which would allow us to obtain the soft function as well as the CS kernel. And the "double ratio"; which allows us to achieve a high degree of statistical precision, but only produces the CS kernel. The matching of our result to Minkowski space is achieved through the mapping of the complex auxiliary field directional vector to the Wilson line rapidity. We present a preliminary extraction of the CS kernel using the "double ratio", and discuss the methodology employed.

    ↳ hep-lathep-phhep-thnucl-thPoS(2026)·0 citations
27. 27*

    BMW/DMZ calculation of the hadronic vacuum polarisation for the muon magnetic moment

    Finn M. Stokes🇦🇺 · Alessandro Cotellucci🇩🇪 · Michel Davier🇫🇷 · Zoltan Fodor🇩🇪 · Fabian Frech🇺🇸 · Davide Giusti🇩🇪 · Andrey Yu. Kotov🇩🇪 · Laurent Lellouch🇫🇷 · Bogdan Malaescu🇫🇷 · Sophie Mutzel🇫🇷 · Kalman K. Szabo🇩🇪 · Balint C. Toth🇩🇪 · Gen Wang🇫🇷 · Zhiqing Zhang🇫🇷

    For twenty years, a persistent discrepancy between experimental measurements and theoretical calculations of the muon anomalous magnetic moment have provided tantalising hints of new physics. In recent years, improvements to the experimental precision have appeared to make the tension stronger and stronger. However, at the same time, our lattice calculation overturned the theoretical consensus, completely eliminating the tension. I will present the latest results from the Budapest-Marseille-Wuppertal (BMW) and DMZ collaborations, with a hybrid determination of the hadronic vacuum polarisation contribution to a precision of 0.45%

    ↳ hep-lathep-phhep-thPoS(2026)·4 citations
28. 28*

    Non-local nonstabiliserness in Gluon and Graviton Scattering

    John Gargalionis🇦🇺 · Nathan Moynihan🇬🇧 · Michael L. Reichenberg Ashby🇬🇧 · Ewan N. V. Wallace🇦🇺 · Chris D. White🇬🇧 · Martin J. White🇦🇺

    The property of non-stabiliserness, or ``magic'', is of interest in quantum computing due to its role in developing fault-tolerant quantum algorithms with genuine computational advantage over classical counterparts. There has been much interest in quantifying magic in various physical systems, in order to probe how to produce and enhance it. The production of magic has previously been quantified in gluon and graviton scattering, in the so-called helicity basis relating particle spins with momentum directions. For a basis-independent statement, one should instead use the recently developed concept of non-local non-stabiliserness, and our aim in this paper is to derive how this varies for gluon and graviton scattering processes. Our results show that, for many initial states, including those produced with polarised beams, the helicity basis coincides with a basis in which the non-local magic is manifest, providing a physical motivation for using the helicity basis to study quantum information quantities. However, this property breaks upon adding additional operators to the Yang-Mills Lagrangian, as would be the case in new physics scenarios.

    ↳ hep-thhep-phquant-ph11 citations
29. 29*

    $e^{+}{e}^{-}\to s\bar{s}$ at $\sqrt{s}=250$ GeV at future linear colliders

    J.P. Márquez🇪🇸 · R. Pöeschl🇫🇷 · A. Irles🇪🇸 · F. Richard🇫🇷

    The forward-backward asymmetry ($A_{FB}$) in light-quark production is a sensitive probe of the electroweak sector and potential flavour-dependent BSM effects. We present a study of $e^{+}{e}^{-}\to s\bar{s}$ at $\sqrt{s}=250$ GeV at future linear colliders, using full ILD simulation and reconstruction tools for ILC and LCF@CERN. We assess the impact of particle identification on charge reconstruction and $A_{FB}$ extraction, considering software improvements using Comprehensive PID (CPID) for optimal $dE/dx$ usage, as well as hardware scenarios including cluster counting ($dN/dx$) and ideal TPC performance. Statistical precision gains are evaluated, with corrections for charge misidentification and acceptance applied. Results indicate that precise $A_{FB}^{s\bar{s}}$ measurements are feasible and that advanced PID is key to maximising sensitivity to electroweak and new-physics effects.

    ↳ hep-exhep-phEur.Phys.J.Plus(2026)·0 citations
30. 30*

    Atmospheric neutrino constraints on Lorentz invariance violation with the first six detection units of KM3NeT/ORCA

    KM3NeT Collaboration · O. Adriani · A. Albert · A. R. Alhebsi · S. Alshalloudi · S. Alves Garre · F. Ameli · M. Andre · L. Aphecetche · M. Ardid · S. Ardid · J. Aublin and 285 other authors

    Lorentz invariance is a fundamental symmetry underlying both the Standard Model of particle physics and General Relativity. Testing its validity provides a direct means of searching for new physics emerging near the Planck scale. A search for isotropic Lorentz invariance violation with 1.4 years of atmospheric neutrino data collected by a partial configuration of the KM3NeT/ORCA detector comprising six detection units is presented. No evidence for such violation is found; thus, competitive limits are set on a subset of isotropic Lorentz invariance violating coefficients, which complement and extend existing experimental constraints.

    ↳ hep-exhep-ph3 citations
31. 31*

    Post-inflationary axion constraints from the Lyman-$\alpha$ forest

    Olga Garcia-Gallego🇬🇧 · Vid Iršič🇬🇧 · Matteo Viel🇮🇹 · Martin G. Haehnelt🇬🇧 · James S. Bolton🇬🇧

    Among the most compelling cold dark matter candidates, the axion has recently been subject to a wide range of astrophysical studies aiming to constraints its properties. We present updated bounds on the isocurvature fraction, $f_{\mathrm{iso}}$, which parameterizes the contribution of isocurvature perturbations induced by post-inflationary produced axion-like particles (ALPs) to the ordinary power spectrum. We use new simulations based on the Sherwood-Relics suite to fit high-resolution Lyman-$\alpha$ forest flux power spectrum data. With the published noise model of the Lyman-$\alpha$ forest data, we find a tentative detection of $f_{\mathrm{iso}}$ = $0.0064_{-0.0014}^{+0.0012}$ (68% C.L), after accounting for the degenerate effect of IGM thermal evolution. With a more conservative modelling of the residual noise in the data, the upper bound is weakened to $f_{\mathrm{iso}}<0.0084$ (95% C.L), which translates into an ALP temperature-independent mass $m_a>1.73\times 10^{-18}$eV. Our constraints are stronger than bounds derived from large-scale structure probes at higher and lower redshifts and are competitive with those derived from UV luminosity function data. Interestingly, the best current Lyman-$\alpha$ forest data prefers a non-zero contribution from isocurvature modes.

    ↳ astro-ph.COhep-phhep-th7 citations
32. 32*

    The MexNICA Collaboration in the MPD-NICA Experiment at JINR: Experimental and Theoretical Achievements

    Alfredo Raya🇲🇽 · Mauricio Alvarado · Juan Anzúrez · Alejandro Ayala🇲🇽 · Wolfgang Bietenholz🇲🇽 · Salomón Borjas García · Eleazar Cuautle🇲🇽 · Pedro E. García González · Irving Iván Gaspar Gregorio · Isabel Domínguez🇲🇽 · Luis Alberto Hernández🇲🇽 · Maribel Herrera and 12 other authors

    The MexNICA Collaboration coordinates the activities of Mexican scientists, engineers, postdoctoral fellows and students in the Multi-Purpose Detector experiment at the Nuclotron-based Ion Collider fAcility of the Joint Institute for Nuclear Research in Dubna, Russia. Established in 2016, the collaboration brings together five Mexican institutions whose contributions span detector development as well phenomenological and theoretical studies, including modeling by means of Monte Carlo simulations. This work summarizes the main achievements of MexNICA, consisting of the development of the miniBeBe trigger detector as well of results of phenomenological investigations of the baryon-rich region in the QCD phase diagram accessible at NICA energies, and theoretical advances based on lattice QCD and effective models.

    ↳ nucl-exhep-lathep-phhep-th+20 citations
33. 33*

    Higher-Spin and Higher-Point Constraints on Stringy Amplitudes

    Ivano Basile🇩🇪 · Grant N. Remmen🇺🇸 · Georgina Staudt🇩🇪

    We employ multiparticle factorization to constrain deformations of tree-level open string amplitudes. Assuming minimal degeneracy among intermediate states of the same spin up through the second excited level, we find that the Regge intercept among all amplitudes of the Koba-Nielsen type can be uniquely fixed using seven-point factorization, precisely matching the bosonic string. Moreover, we produce novel constraints on deformations of the worldsheet integrand. We then turn to deformations of superstrings, with massless external states and arbitrary spectral degeneracy, using soft kinematics. Accounting for the infinite tower of higher-spin resonances, we obtain novel multipositivity bounds to leading and subleading order in the large-level limit. We apply these bounds to the simplest factorizable satellite deformation in the family of amplitudes found by Gross, showing that any deformation of four-point string amplitudes of this type is forbidden by unitarity. Our results reinforce the folklore that the higher-spin tower of string excitations is dramatically more rigid than any finite number of species.

    ↳ hep-thhep-phPRD(2026)·9 citations
34. 34*

    From BPS geodesics to mode-driven dynamics in the scattering of multiple BPS vortices

    Alberto Alonso-Izquierdo🇪🇸 · Maximilian Bachmaier🇩🇪 · Andrzej Wereszczynski🇵🇱

    We analyze how the geodesic motion in the 3- and 4-vortex sectors of the Abelian-Higgs model at critical coupling is deformed by the excitation of a massive bound mode. We find that the geodesics corresponding to BPS solutions with enhanced symmetry remain unchanged, although the direction of the actual motion depends on the mode-generated force, i.e., a force arising from the change of the mode frequency along the geodesic. In a generic case, for example in head-on collisions between the axially symmetric 1- and 2-vortex or between two 2-vortices, the vortex trajectories can differ strongly from the BPS geodesic. This enhances the chaotic behavior in the formation of the final state.

    ↳ hep-thhep-phnlin.CDPRD(2026)·7 citations
35. 35*

    Reheating after Starobinsky Inflation in the Jordan Frame

    Gláuber C. Dorsch🇧🇷 · Luiz Carlos Miranda🇧🇷 · Nelson Yokomizo🇧🇷

    We investigate gravitational reheating in the Starobinsky model in the Jordan frame, where inflation is driven by an $R^2$ modification of gravity with no explicit inflaton field. In this description, reheating proceeds exclusively through gravitational particle production triggered by the oscillations of the Ricci scalar after the end of inflation. We analyze the post-inflationary background evolution and show that an effective fluid emerging from the modified gravitational dynamics behaves as pressureless matter during the oscillatory phase. Including the backreaction of the produced particles, we demonstrate that the Ricci scalar oscillations acquire an exponential damping, consistently terminating particle production. Solving the coupled background and Boltzmann equations, we obtain a reheating temperature $T_{\mathrm{reh}}\sim 2\times 10^9$ GeV. We finally compare the Jordan and Einstein frame descriptions and argue that, although classically equivalent, they can lead to distinct microphysical interpretations and quantitative predictions for reheating once quantum effects are taken into account.

    ↳ gr-qchep-ph2 citations
36. 36*

    The dark fate of ultra-faint dwarfs: Gravothermal collapse in action

    Moritz S. Fischer🇩🇪 · Hai-Bo Yu🇺🇸

    Ultra-faint dwarf (UFD) galaxies are a promising probe for dark matter (DM) physics as they are the most DM-dominated systems known. The Milky Way (MW) hosts many UFDs for which the properties of their DM distribution have been inferred from measurements of their stellar kinematics. If DM has self-interactions beyond gravity, the UFD halos may undergo a gravothermal evolution, giving rise to a population of galaxies with more diverse DM density profiles. We investigate DM densities of MW UFDs in self-interacting dark matter (SIDM) models, with an aim of determining the stage of gravothermal evolution for their halos. Therefore, we employed idealised high-resolution SIDM N-body simulations targeted to a MW-like system and compared the properties of simulated satellites to those of the observed UFDs. We find that the gravothermal evolution of SIDM halos produces diverse DM distributions, aligning with observations of the MW UFDs. Most of the UFDs have high DM densities, indicating that their halos have passed the period of maximum core expansion and entered the collapse phase, i.e. their central density may increase with time. The depth to which they have evolved into the gravothermal collapse may vary strongly across the satellites. This allows SIDM to account for the diversity in their DM densities. Moreover, the acceleration of the gravothermal evolution by tidal stripping can help to explain the diversity of the UFDs, as the ones with smaller pericentre distances require having evolved further into the gravothermal catastrophe. Large SIDM cross-sections of $\sigma /m_{\chi }\approx$ 80 cm${}^2$ g${}^{-1}$ at a velocity of $v\approx$ 20 km s${}^{-1}$ are plausible, as the halo densities of MW UFDs are consistent with the gravothermal evolution predicted in SIDM, with most of them being in the collapse phase.

    ↳ astro-ph.COastro-ph.GAhep-phAstron.Astrophys.(2026)·6 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.