Mon·Dec 8, 2025Monday·December 8, 2025

1. 01*

   Jet Charge with Global Event Shapes: Probing Quark Flavor Dynamics

   Yang-Ting Chien🇺🇸 · Sonny Mantry🇺🇸

   We propose measuring the jet electric charge of jet regions, defined within the framework of global event shapes, as a probe of quark flavor dynamics within the nucleon and the hadronization process. In particular, we consider a measurement of the jet region charge while simultaneously keeping track of the energy flow throughout the event, as characterized by the global event shape. As a concrete example, we focus on the measurement of the 1-Jettiness jet charge ($Q$), the jet charge of the jet region ($J$) defined within the framework of the 1-Jettiness global event shape (${\tau }_1$) for the Deep Inelastic Scattering (DIS) process, $e^{-}+p\to e^{-}+J+X$, with unpolarized or longitudinally polarized protons. The 1-Jettiness distribution, binned according to jet charge, allows for enhanced quark flavor separation of the initial state unpolarized or polarized PDFs. On the other hand, the jet charge distribution binned by 1-Jettiness can serve as a probe of quark flavor dynamics in the final state hadronization process. We derive a factorization theorem for simultaneous measurements of ${\tau }_1$ and $Q$ in the resummation region, ${\tau }_1\ll P_{J_T}$, where $P_{J_T}$ denotes the transverse momentum of the jet region. The factorization theorem contains a new universal charged jet function, generalizing the standard jet function to include a jet charge measurement. Therefore these universal functions can be extracted from a global analysis of N-jettiness and thrust at $e^{+}{e}^{-}$ colliders. We provide simulation studies to demonstrate the sensitivity of the 1-Jettiness jet charge observable to quark flavor dynamics in nucleon structure and explore the possibility of probing the final state hadronization process. This observable is well-suited for applications with existing HERA data and the future Electron-Ion Collider (EIC).

   hep-phhep-exnucl-thPRD(2026)·2 citations
2. 02*

   Illuminating sequential freeze-in dark matter with dark photon signal at the CERN SHiP experiment

   Xinyue Yin🇨🇳 · Sibo Zheng🇨🇳

   Single-field freeze-in dark matter barely leaves observable footprints in dark matter direct detection, collider or fixed-target experiments, which can be altered in the two-field context. In this work, we consider sequential freeze-in dark matter through signals of dark photon mediator with a mass range of $m_{A^{\prime }}\sim 10^{-2}-10$ GeV covered by the proposed SHiP experiment. We show that the dark charge is fixed to be $e^{\prime }\sim 1.3\times 10^{-12}$ and the mixing parameter is restricted to $10^{-11}\le ϵ<10^{-8}-10^{-7.5}$, as a result of the out-of-equilibrium condition of dark photon and the observed relic abundance of dark matter. Within this $ϵ$ region, the 5(15)-year data of proton bremsstrahlung process for the dark photon, assuming vector meson (dipole) dominance, excludes $ϵ\ge 10^{-8.5}(10^{-7.9})$ at 90\% confidence level, implying only a narrow region of $ϵ$ close to $\sim 10^{-11}$ left for alternative tests.

   hep-phastro-ph.COhep-exPRD(2026)·3 citations
3. 03*

   What can we learn from the radiative decays of the $D_{s1}(2460)$ meson?

   Hai-Long Fu🇨🇳 · Feng-Kun Guo🇨🇳 · Christoph Hanhart🇩🇪 · Alexey Nefediev🇩🇪

   We study the radiative decays $D_{s1}(2460)\to \gamma D_{s0}^{\ast }(2317)$ and $D_{s1}(2460)\to \gamma D^0{K}^{+}/\gamma D^{+}{K}^0$ and argue that their simultaneous experimental measurement, or at least a constraint on the ratio of the corresponding branching fractions, can allow one to probe the nature of the $D_{s0}^{\ast }(2317)$ and $D_{s1}(2460)$ mesons.

   hep-phhep-exPRD(2026)·6 citations
4. 04*

   Neutrino masses, ${\delta }_{\mathrm{PMNS}}$, and $m_{\beta \beta }$ in SO(10)

   Shaikh Saad🇸🇮 · Qaisar Shafi🇺🇸

   We explore the leptonic sector of a recently proposed supersymmetric SO(10) model with supersymmetry breaking in the 3-10 TeV range. A new ingredient in this work is the requirement that the observed baryon asymmetry is explained via non-thermal leptogenesis, which can be realized in a large class of supersymmetric hybrid inflation models including SO(10). We provide estimates for the masses of the three Standard Model neutrinos (with the lightest mass $m_1\approx 5$ meV) as well as the three right-handed neutrinos ($M_1\approx 10^9$ GeV and $M_{2,3}\approx 10^{13}$ GeV). The best fit estimate for the leptonic CP violating parameter ${\delta }_{\mathrm{PMNS}}\approx 235^{\circ }$, and the value of the neutrinoless double beta decay mass parameter $m_{\beta \beta }\approx 0.18$ meV. A numerical analysis broadens the predicted range for ${\delta }_{\mathrm{PMNS}}$ ($100^{\circ }$-$300^{\circ }$), but leaves largely intact the predictions for the six (light and heavy) neutrino masses and $m_{\beta \beta }$. Our statistical analysis, which yields the likelihood-predicted ranges of the observables, is fully consistent with JUNO's newly released first measurement of reactor neutrino oscillations in the $\Delta m_{12}^2$-${\sin }^2{\theta }_{12}$ plane, with JUNO improving the precision by a factor of 1.6 relative to the combination of all previous measurements. The implementation of successful non-thermal leptogenesis allows us to provide estimates for the inflaton mass ($m_{\chi }\approx 7\times 10^9$ GeV) and the reheating temperature ($T_{\mathrm{RH}}\approx 4\times 10^6$ GeV).

   hep-phJHEP(2026)·2 citations
5. 05*

   Gauge-Invariant Bubble Nucleation and Gravitational Waves from First-Order Electroweak Phase Transitions

   Jie Liu🇨🇳 · Renhui Qin🇨🇳 · Ligong Bian🇨🇳

   A long-standing problem in electroweak phase transition studies is the spurious gauge dependence of bubble nucleation rate calculations, which introduces large systematic uncertainties in predictions of gravitational waves and related cosmological phenomena. We address this issue by presenting a systematic study of gauge-invariant bubble nucleation within a phenomenologically realistic effective field theory framework. Using the three-dimensional thermal effective field theory formalism with a consistent power-counting scheme, we rigorously establish the gauge invariance of the physical nucleation rate up to two-loop order. This proof eliminates the gauge-parameter dependence of key phase transition parameters, providing a robust theoretical foundation for precise calculations of gravitational waves, electroweak baryogenesis, and primordial magnetogenesis.

   hep-phastro-ph.COhep-thPRD(2026)·7 citations
6. 06*

   The Dichotomous Nature of the $\sigma$ Meson and the Nucleon D-Term

   Zanbin Xing🇨🇳 · Khépani Raya🇪🇸 · Yu-xin Liu🇨🇳 · Lei Chang🇨🇳

   Employing a symmetry-preserving contact-interaction formulation of the Dyson-Schwinger equations in quantum chromodynamics (QCD), we examine the identity of the $\sigma$ meson and its implications for the gravitational structure of hadrons. In this framework, the scalar meson emerges as the chiral partner of the pion, with both states' properties tightly connected to the mechanisms of mass generation in QCD. We find that, above a critical coupling that triggers dynamical chiral symmetry breaking, the D-terms of the constituent quark, the pion, and $\sigma$ saturate at fixed values $D_{q,\pi ,\sigma }=-1/3,-1,-7/3$. By examining the coupling strength evolution of the D-terms, this pattern follows naturally once a dual nature for the $\sigma$ meson is recognized: it behaves both as a quark-antiquark composite and as a dilaton arising from spontaneous scale symmetry breaking. This unified picture yields the prediction $D_N\sim -3$ for the nucleon D-term, consistent with contemporary lattice-QCD, continuum, and dispersive studies.

   hep-phPLB(2026)·4 citations
7. 07*

   A comprehensive study of $B$, $B_s$ and $B_c$ meson semitauonic modes in potential quark model

   Sonali Patnaik🇮🇳

   In this work, we derive the form factors and compute the branching fractions for the semitauonic decay modes, $B\to D^{(\ast )}\tau {\nu }_{\tau }$, $B_s\to D_s^{(\ast )}\tau {\nu }_{\tau }$, $B_c\to {\eta }_c(J/\psi )\tau {\nu }_{\tau }$, and $B_c\to D^{(\ast )}\tau {\nu }_{\tau }$ within the \emph{Relativistic Independent Quark (RIQ) Model}, emphasizing a quark potential model based analysis of these transitions. We outline the essential elements of the model, incorporating corrections from residual interactions and center-of-mass motion, and perform a comprehensive study of the form factors across the full physical kinematic range of $q^2$. The resulting predictions demonstrate consistency and good agreement with existing theoretical approaches and experimental measurements. Motivated by recent observations of polarization observables at LHCb and Belle, we further evaluate these quantities within our framework and find results compatible with Standard Model (SM) expectations. The predictions presented here serve as theoretical input in decay channels for which Lattice QCD results remain limited, offering guidance for future experimental and Lattice efforts. Thus, semileptonic $B$ decays continue to serve as precise and discerning probes of the fundamental mechanisms governing flavor transitions in the SM.

   hep-phPoS(2026)·0 citations
8. 08*

   Phenomenological studies of exclusive heavy-quarkonium electroproduction at NLO

   Chris A. Flett🇫🇷

   Using the next-to-leading order (NLO) coefficient functions for exclusive electroproduction of heavy vector mesons derived in our previous work, we perform various phenomenological studies of exclusive electroproduction in $ep$ collisions relevant for both the existing measurements from HERA, and the forthcoming Electron-Ion Collider (EIC). We compare our cross-section results to HERA data across a broad range of photon virtualities $Q^2$ and ${\gamma }^{\ast }p$ centre-of-mass energies, provide predictions for upcoming EIC measurements and conclude with a discussion on the necessity of resumming logarithmically enhanced contributions in $J/\psi$ electroproduction.

   hep-phEPJC(2026)·2 citations
9. 09*

   Nearly Degenerate Majorana Dark Matter and Its Self-Interactions in a Gauged $U(1{)}_{L_{\mu }-L_{\tau }}$ Model

   Kwei-Chou Yang🇹🇼

   We propose a model of nearly degenerate Majorana dark matter (DM) in a gauged $U(1{)}_{L_{\mu }-L_{\tau }}$ extension of the Standard Model. Spontaneous symmetry breaking generates a dominant Majorana mass via a strong Yukawa coupling, splitting the dark fermion into two nearly degenerate states. The lighter state (${\chi }_{-}$) is the DM candidate, with an allowed mass of $\sim 10$ GeV to several hundred GeV. Crucially, within the $10\sim 75$ GeV mass range and a scalar mediator at the tens of MeV scale, this strong coupling dictates the thermal relic abundance and induces significant elastic self-interactions. These self-interactions naturally resolve small-scale structure anomalies, such as the core-cusp problem, while satisfying massive cluster constraints. Furthermore, we place stringent joint constraints on the scalar mass and the Higgs mixing angle $\alpha$ using the latest LZ 2025 direct detection data. The model's gauge boson $Z^{\prime }$ maintains early-Universe thermal equilibrium and accommodates the muon anomalous magnetic moment $(g-2{)}_{\mu }$, remaining consistent with updated cosmological and experimental bounds.

   hep-phastro-ph.COastro-ph.GAastro-ph.HE+10 citations
10. 10*

    Machine Learning-Informed 3+1 Sterile Neutrino Global Fits using Posterior Density Estimation of Electron Disappearance Data

    Joshua Villarreal🇺🇸 · Julia Woodward🇺🇸 · John Hardin🇺🇸 · Janet Conrad🇺🇸

    Global analyses of particle physics data are integral for validating and scrutinizing published results of experiments. Global fits of anomalous oscillation data which search for one or more eV-scale sterile neutrinos are particularly challenging both to evaluate and to reconcile in the global picture. Fits (especially joint ones) to oscillation data suffer from significant computational burdens, such as likelihood intractability, making traditional Markov Chain-Monte Carlo all but impossible. Given evidence both supporting and challenging beyond Standard Model physics across neutrino experiments of various baselines, energies, and detection techniques, the global search for sterile neutrinos requires additional tools in order to determine whether sterile neutrinos remain a viable solution to unexplained anomalies. Furthermore, both a Bayesian and frequentist interpretation of sterile neutrino data is needed for a complete assessment of longstanding tensions in the field. Techniques from the machine learning subfield of simulation-based inference have a natural application to such a problem. In this contribution, we illustrate some of the outstanding questions of the global picture of light sterile neutrinos by focusing on experiments searching with the disappearance of electron (anti)neutrinos, and look to posterior density estimation strategies to craft answers, including comparisons to a machine-learning-based frequentist approach.

    hep-phEPJC(2026)·2 citations
11. 11*

    Three-loop jet function for boosted top quarks

    Alberto M. Clavero🇪🇸 · Vicent Mateu · Maximilian Stahlhofen🇩🇪

    We present the calculation of the inclusive jet function for highly energetic heavy quarks at order $\mathcal{O}({\alpha }_s^3)$ using boosted Heavy-Quark Effective Theory (bHQET). This jet function describes the effect of collinear radiation emitted by energetic heavy quarks on observables dependent on the jet invariant mass $M$. In particular, we focus on the regime $M^2-m^2\ll m^2$, which is relevant for boosted top quark production at high-energy colliders in the resonance region. Our results are consistent with non-Abelian exponentiation and reproduce the known cusp and non-cusp anomalous dimensions up to three loops. We also verify that the $n_{\ell }^2{\alpha }_s^3$ contribution, with $n_{\ell }$ denoting the number of light quark flavors, agrees with predictions from renormalon calculus. This calculation completes the list of ingredients required for the N${}^3$LL${}^{\prime }$ resummed (self-normalized) thrust distribution, an essential component for calibrating the top quark mass parameter in parton-shower Monte Carlo generators. It likewise contributes to the invariant-mass distribution of reconstructed top quarks, enabling precise mass determinations at future lepton colliders. Finally, we determine the relation between the pole and two short-distance jet-mass schemes at $\mathcal{O}({\alpha }_s^3)$ and provide an estimate of the non-logarithmic part of the four-loop jet function based on renormalon dominance.

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

    Dark Matter implications from the LZ, PandaX-4T and XENONnT Data

    Haipeng An🇨🇳 · Fei Gao🇨🇳 · Jia Liu🇨🇳 · Minghao Liu🇺🇸 · Haoming Nie🇨🇳 · Changlong Xu🇨🇳

    We investigate a possible dark matter origin of the high-energy nuclear-recoil-like events in data from liquid xenon time projection chamber experiments, including LZ, PandaX-4T, and XENONnT, which cannot be explained by standard elastic spin-independent WIMP scattering. Using our unified DIAMX framework, built on openly available data and likelihood models, we perform the first combined profile-likelihood fits to multiple WIMP-search datasets with a total exposure of approximately 8.8 tonne $\times$ year. We consider two broad classes of dark matter-nucleon interactions, involving either velocity-dependent cross sections or inelastic (endo- and exothermic) scattering, which can reproduce the observed high-energy recoil spectrum, reaching local significances up to $3.5\sigma$. We further quantify the impact of ${}^{124}$Xe double electron capture (DEC) backgrounds, finding that variations in the poorly known DEC charge yields can shift the inferred significances from a null-like result to $3.5\sigma$. We further note that extending the same analysis to data from all three experiments with recoil energies up to $300\mathrm{keV}$, when available, will provide a powerful test of the dark matter interpretation, since the ${}^{124}$Xe DEC background is expected to be negligible in this high-energy range.

    hep-phhep-ex7 citations
13. 13*

    Dijet bounds on third-generation four-quark operators

    Maximilian Freiheit🇩🇪 · Ulrich Haisch🇩🇪

    We use dijet measurements from the Large Hadron Collider to constrain ten third-generation four-quark operators in the Standard Model effective field theory. At tree level, only the five operators involving four bottom quarks are directly constrained, but renormalization group (RG) effects allow all ten operators to be probed. Our analysis includes the dominant leading-logarithmic RG contributions up to two-loop order. The resulting bounds for the first five operators are nominal stronger or comparable to current limits, while those for the remaining operators remain weak despite the inclusion of logarithmically enhanced corrections.

    hep-phhep-exJHEP(2026)·2 citations
14. 14*

    Untangling the IBP Equations

    Junhan W. Liu🇬🇧 · Alexander Mitov🇬🇧

    In this work, we present an algorithm for the diagonalization of the Integration-by-Parts (IBP) equations. Diagonalized IBP equations are indispensable for reducing loop integrals with high numerator powers to master integrals and for solving IBP identities in closed analytic form. A prime example is provided by multivariate Mellin representations of loop amplitudes and cross sections. The extension of these methods to other multivariate recurrence relations is also discussed. As a by-product of our diagonalization procedure, we show how the IBP equations can be cast into an efficient, fully triangular form that is well suited for computer implementation. Several complicated topologies have been computed.

    hep-phhep-th7 citations
15. 15*

    Strongly Coupled Quantum Forces

    Yuval Grossman🇺🇸 · Chinhsan Sieng🇺🇸 · Xun-Jie Xu🇨🇳 · Bingrong Yu🇺🇸

    Quantum forces are long-range interactions originating from vacuum fluctuations of mediator fields. Such forces inevitably arise between ordinary matter particles whenever they couple to light mediator species. Conventional computations of quantum forces rely on evaluating one-loop Feynman diagrams of the relevant scattering processes. In this work, we introduce a novel framework to compute quantum forces. Instead of relying on perturbative scattering amplitudes, we directly evaluate the quantum fluctuations of the mediator field by solving its quantized equation of motion with appropriate boundary conditions. This approach remains valid beyond the Born approximation and thus applies to regimes of strong coupling between the mediator and matter fields. In the weak-coupling limit, our results reproduce the known expressions from the Feynman diagram approach. In the strong-coupling regime, the result is modified by a factor that can suppress or enhance the effect. In contrast to classical forces, quantum forces intrinsically violate the superposition principle. Our approach may therefore offer a useful tool for probing non-perturbative effects in the infrared regime.

    hep-phhep-th2 citations
16. 16*

    A Framework for Quantum Simulations of Energy-Loss and Hadronization in Non-Abelian Gauge Theories: SU(2) Lattice Gauge Theory in 1+1D

    Zhiyao Li🇺🇸 · Marc Illa🇺🇸 · Martin J. Savage🇺🇸

    Simulations of energy loss and hadronization are essential for understanding a range of phenomena in non-equilibrium strongly-interacting matter. We establish a framework for performing such simulations on a quantum computer and apply it to a heavy quark moving across a modest-sized 1+1D SU(2) lattice of light quarks. Conceptual advances with regard to simulations of non-Abelian versus Abelian theories are developed, allowing for the evolution of the energy in light quarks, of their local non-Abelian charge densities, and of their multi-partite entanglement to be computed. The non-trivial action of non-Abelian charge operators on arbitrary states suggests mapping the heavy quarks to qubits alongside the light quarks, and limits the heavy-quark motion to discrete steps among spatial lattice sites. Further, the color entanglement among the heavy quarks and light quarks is implemented using hadronic operators, and Domain Decomposition is shown to be effective in quantum state preparation. Scalable quantum circuits that account for the heterogeneity of non-Abelian charge sectors across the lattice are used to prepare the interacting ground-state wavefunction in the presence of heavy quarks. The discrete motion of heavy quarks between adjacent spatial sites is implemented using fermionic SWAP operations. Quantum simulations of the dynamics of a system on $L=3$ spatial sites are performed using IBM's $ibm\_pittsburgh$ quantum computer using 18 qubits, for which the circuits for state preparation, motion, and one second-order Trotter step of time evolution have a two-qubit depth of 398. A suite of error mitigation techniques are used to extract the observables from the simulations, providing results that are in good agreement with classical simulations. The framework presented here generalizes straightforwardly to other non-Abelian groups, including SU(3) for quantum chromodynamics.

    ↳ quant-phhep-lathep-phnucl-th29 citations
17. 17*

    The Glow of Axion Quark Nugget Dark Matter: (IV) CMB Spectral and Anisotropy Signatures

    Fereshteh Majidi🇨🇦 · Xunyu Liang🇨🇦 · Michael Sekatchev🇨🇦 · Ludovic Van Waerbeke🇨🇦 · Ariel Zhitnitsky🇨🇦

    Axion quark nuggets (AQNs) are macroscopic dark-matter candidates, with masses of the order of a few grams to a kilogram and sub-micron radius, thought to form at the Quantum Chromo Dynamic era through axion-induced charge separation. This framework naturally links the dark and visible matter abundances (${\Omega }_{\mathrm{DM}}\sim {\Omega }_{\mathrm{visible}}$) and provides a mechanism for generating the baryon-antibaryon asymmetry where dark matter is composed of matter AQNs and antimatter AQNs. Although behaving as cold dark matter on cosmological scales, baryons annihilate with antimatter AQNs, producing ionizing high-energy photons. The resulting energy injection may imprint spectral distortions on the cosmic microwave background (CMB) and modify the reionization history. Using a modified version of the \texttt{CLASS} Boltzmann code we compute the impact of this energy injection on the $\mu$ and $y$ spectral distortion parameters as well as on the optical depth. We find that (1) the CMB anisotropies remain essentially unaffected by baryon annihilation, and (2) the associated spectral distortion signatures lie within the sensitivity reach of proposed CMB spectral distortion missions. Finally, we discuss the similarities and differences between the AQN scenario and annihilating or decaying dark matter models.

    ↳ astro-ph.COastro-ph.HEhep-phJCAP(2026)·3 citations
18. 18*

    On the Weyl anomaly for chiral fermions

    Enrique Alvarez🇪🇸 · Luis Alvarez-Gaume🇺🇸 · Jesus Anero🇪🇸 · Carmelo P Martin🇪🇸

    We compute the parity-odd part of the Weyl anomaly for chiral fermions in a background gravitational field. We start from a manifestly real form of the Lagrangian (that is, not only real up to a total derivative), and we regularize it by means of Pauli-Villars fermions. All parity-odd terms in the anomaly cancel in the integrand, so that the result of the anomaly is necessarily parity-even.

    ↳ hep-thhep-phPRD(2026)·2 citations
19. 19*

    Hadronic Emissions from the Microquasar V4641 Sgr, SS433, and its implications in the Diffuse Galactic Emission

    Basanti Paul🇮🇳 · Abhijit Roy🇮🇹 · Jagdish C. Joshi🇮🇳 · Debanjan Bose🇮🇳

    Microquasars (MQs) are Galactic binary systems, consisting of a star and a compact object, a neutron star or a stellar mass black hole, which accretes matter from its companion star and gives rise to relativistic jets. Recent detection of very-high-energy (VHE; $E\gtrsim 100,\text{GeV}$) and ultra-high-energy (UHE; $E\gtrsim 100,\text{TeV}$) gamma-rays by LHAASO, HAWC and HESS from the MQ V4641 Sgr and SS 433 suggests them as Galactic PeVatrons. In this work, we studied a hadronic origin of the observed TeV-PeV gamma-ray emission from these MQs. We considered the hadronic scenario where the gamma-rays are produced by the interaction of relativistic protons in the MQ jet with the stellar wind. We fitted our model with observed data and constrained physical parameters like the hadronic jet power fraction, the proton spectral index, the maximum proton energy and the jet bulk Lorentz factor. Our best-fit model shows hard proton spectra ($1.84-2.44$) and maximum proton energies between 1 and 5 PeV. We also estimated the all-flavor neutrino fluxes corresponding to the gamma-ray fluxes from the hadronic model and found that V4641 sgr can be detected by next-generation neutrino telescopes like KM3NeT-ARCA and TRIDENT. Furthermore, we modeled a synthetic population of Galactic MQs and estimated their contribution to the diffuse TeV-PeV gamma-ray flux. For the inner Galaxy PSR contribution dominates in the range 10-100 TeV, and above 100 TeV diffused cosmic ray interactions with the molecular clouds is most dominant. We find that a population $\sim 14$ MQs is required to explain the LHAASO data above 100 TeV. For the outer Galaxy, we show that MQs are the dominant class of sources, and we constrain their population $\sim$14. Our findings strongly suggest that MQs are efficient particle accelerators, contributing to Galactic PeVatrons and potential multimessenger sources in our Galaxy.

    ↳ astro-ph.HEhep-ph0 citations
20. 20*

    Feynman Integral Reduction and Landau Singularities

    Federico Coro🇧🇪 · Pavel P. Novichkov🇧🇪 · Ben Page🇧🇪 · Qian Song🇧🇪

    We propose that Feynman integral reduction is controlled by solutions of the Landau equations. We study integral relations with prescribed propagator powers using syzygy methods and discuss how syzygies can be expressed as a sum over components of the Landau singularity locus. This leads to a determinantal approach to solving the syzygy problem, giving rise to highly compact and physically transparent solutions. We demonstrate the method in applications to planar two-loop five-point integrals relevant for the $pp\to t\overline{t}H$ process. Our results suggest an efficient method of Feynman integral reduction and provide a novel physical perspective on the problem.

    ↳ hep-thhep-phPRD(2026)·5 citations
21. 21*

    Differentially rotating neutron stars with dark matter cores

    Lorenzo Cipriani🇮🇹 · Violetta Sagun🇬🇧 · Kalin V. Staykov🇧🇬 · Daniela D. Doneva🇪🇸 · Stoytcho S. Yazadjiev🇧🇬

    Dark matter is expected to accumulate inside neutron stars, modifying the structure of isolated stars and influencing both the dynamics of binary mergers and the evolution of the resulting hypermassive remnants. Since differential rotation is the primary mechanism delaying the collapse of these remnants, understanding its behavior is crucial when assessing the impact of an embedded dark component. In this work, we extend the numerical code RNS to describe two gravitationally coupled fluids in differential rotation, with baryonic matter modeled by a realistic nuclear equation of state and dark matter represented as a self-interacting bosonic condensate. Within this framework, we construct equilibrium sequences for a representative differential rotation law, providing a basis to explore how dark matter may influence the global properties and rotational dynamics of binary neutron star remnants.

    ↳ astro-ph.HEgr-qchep-phnucl-thPRD(2026)·4 citations
22. 22*

    A Reduced Action Integral for Photon-Photon Interactions in Vacuum

    D. Ramsey🇺🇸 · M. S. Formanek🇨🇿 · J. P. Palastro🇺🇸

    Electromagnetic waves propagating through vacuum can polarize virtual electron-positron pairs; this polarization, in turn, nonlinearly modifies their propagation. A semi-classical nonlinear wave equation describing the propagation is derived from the Euler--Heisenberg Lagrangian density, which captures vacuum polarization effects up to the one-loop level. Here, we present a reduced-action-integral approach that enables rapid modeling of nonlinear phenomena arising from the Euler--Heisenberg Lagrangian. Application of the variational principle to the reduced action provides equations of motion for familiar light-pulse parameters, such as spot size, phase, polarization, and phase-front curvature, without requiring full-field simulations. Three examples demonstrate the utility of the approach: phase modulation, birefringence, and frequency mixing.

    ↳ physics.opticshep-ph0 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.