Thu·Jun 19, 2025Thursday·June 19, 2025

1. 01*

   Review of heat and charge transport in strongly magnetized relativistic plasmas

   Igor A. Shovkovy🇺🇸 · Ritesh Ghosh🇺🇸

   We review field-theoretic studies of charge transport in hot relativistic plasmas under strong magnetic fields and extend the analysis to thermal conductivity. The calculations rely on accurately determining the fermion damping rate. Using the Landau-level representation, these damping rates are computed exactly at leading order and incorporated into the Kubo formula to obtain the thermal and electrical conductivity tensors. Our analysis reveals that the mechanisms underlying longitudinal and transverse transport differ significantly. Strong magnetic fields markedly suppress transverse charge transport by confining particles within localized Landau orbits, allowing transport only through quantum transitions between these discrete states. In contrast, longitudinal charge transport is enhanced, as it primarily depends on the reduced scattering probability of particles moving along the direction of the magnetic field. The anisotropy of thermal conductivity is also nontrivial but less pronounced since its underlying transport mechanism is different. We also examine the modification of the Wiedemann--Franz law in strongly magnetized plasmas.

   hep-phnucl-thAAPPS Bull.(2025)·6 citations
2. 02*

   Thermal corrections to Regge trajectories

   R. Cadiz🇺🇸 · M. Loewe🇨🇱 · R. Zamora🇨🇱

   In this work, we investigate the behavior of Regge trajectories in the context of quantum field theory at finite temperature. For this purpose, we employ the $\lambda {\varphi }^3$ model. We first compute the Regge trajectories at zero temperature, establishing a baseline for comparison. As a key novelty, we extended our analysis to finite temperature and derive an analytical expression for the Regge trajectories in this regime. We explore how temperature modifies the structure of the Regge trajectories and analyze the physical implications of these modifications, which arise from the resummation of thermal ladder diagrams. As an interesting consequence, we find the thermal evolution of masses belonging to different Regge trajectories.

   hep-phhep-thPRD(2025)·0 citations
3. 03*

   Thermalization from quantum entanglement: jet simulations in the massive Schwinger model

   Adrien Florio🇩🇪 · David Frenklakh🇺🇸 · Sebastian Grieninger🇺🇸 · Dmitri E. Kharzeev🇺🇸 · Andrea Palermo🇺🇸 · Shuzhe Shi🇨🇳

   We investigate the emergence of thermalization in a quantum field-theoretic model mimicking the production of jets in QCD -- the massive Schwinger model coupled to external sources. Specifically, we compute the expectation values of local operators as functions of time and compare them to their thermal counterparts, quantify the overlap between the evolving density matrix and the thermal one, and compare the dynamics of the energy-momentum tensor to predictions from relativistic hydrodynamics. Through these studies, we find that the system approaches thermalization at late times and elucidate the mechanisms by which quantum entanglement drives thermalization in closed field-theoretic systems. Our results show how thermodynamic behavior emerges in real time from unitary quantum dynamics.

   hep-phhep-thnucl-thquant-phPRD(2025)·27 citations
4. 04*

   Response of Comagnetometer to Exotic Spin-Dependent Couplings

   Yixin Zhao🇨🇳 · Xiang Peng🇨🇳 · Teng Wu🇨🇳 · Hong Guo🇨🇳

   Comagnetometers offer unique advantages in measuring exotic spin-dependent interactions by suppressing magnetic noise. Understanding the frequency response to exotic interactions is essential for evaluating and improving the sensitivity of comagnetometers, as the signals often exhibit distinct spectral features. We conduct theoretical and experimental studies on the frequency response of a differential comagnetometer. We derive analytical expressions for the frequency response of the differential comagnetometer to both magnetic field and exotic couplings, along with the conversion relationship between them. Based on this, we revise the method for determining the axion-nucleon coupling strength with comagnetometers. Furthermore, we introduce a light-shift-based calibration protocol to verify the response to exotic interactions. This work helps predict the sensitivity of comagnetometers in detecting exotic fields and advances the exploration of dark matter.

   hep-phcond-mat.mes-hallhep-exphysics.atom-phPRD(2025)·1 citation
5. 05*

   Ambiguities in the Partial-Wave Analysis of the Photoproduction of Pairs of Pseudoscalar Mesons

   J. Guo🇺🇸 · E. Barriga🇺🇸 · K. Scheuer🇺🇸 · A. Austregesilo🇺🇸 · P. Eugenio🇺🇸 · D. I. Glazier🇬🇧 · B. Grube🇺🇸 · W. Imoehl🇺🇸 · C. A. Meyer🇺🇸 · A. Ostrovidov🇺🇸 · J. R. Stevens🇺🇸

   Applying the technique of partial-wave analysis, there are cases where more than one set of underlying complex-valued amplitudes can describe the measured observables. These ambiguities can sometimes be resolved using additional information, but assumptions are often required. It is known that the partial-wave analysis of two-pseudoscalar meson systems produced in photoproduction with a linearly polarized photon beam is free from discrete ambiguities stemming from the Barrelet zeros when the nucleon spin is ignored. In this article, we show that continuous ambiguities are possible for certain wave sets, even though the discrete ambiguities do not appear. We also explore ways to resolve these ambiguities and determine the maximal amount of information that can be obtained from analyses that suffer from these continuous ambiguities.

   hep-phnucl-exnucl-thPRD(2025)·1 citation
6. 06*

   Mapping the evolution of supernova-neutrino-boosted dark matter within the Milky Way

   Yen-Hsun Lin🇹🇼 · Meng-Ru Wu🇹🇼

   Supernova-neutrino-boosted dark matter (SN$\nu$ BDM) has emerged as a promising portal for probing sub-GeV dark matter. In this work, we investigate the behavior of BDM signatures originating from core-collapse supernovae within the Milky Way (MW) over the past one hundred thousand years, examining both their temporal evolution and present-day spatial distributions. We show that while the MW BDM signature is approximately diffuse in the nonrelativistic regime, it exhibits significant temporal variation and spatial localization when the BDM is relativistic. Importantly, we compare these local MW signatures with the previously proposed diffuse SN$\nu$ BDM (DBDM), which arises from the accumulated flux of all past supernovae in the Universe [Y.-H. Lin and M.-R. Wu, Phys. Rev. Lett. 133, 111004 (2024)]. In the nonrelativistic limit, DBDM consistently dominates over the local diffuse MW BDM signature. Only when the MW BDM becomes ultrarelativistic and transitions into a transient, highly-localized signal can it potentially surpass the DBDM background. This work thus reinforces the importance of DBDM for SN$\nu$ BDM searches until the next galactic SN offers new opportunities.

   hep-phastro-ph.HEPRD(2025)·0 citations
7. 07*

   Cosmic Strings in Multi-Step Symmetry Breaking

   Akifumi Chitose🇯🇵 · Masahiro Ibe🇯🇵 · Satoshi Shirai🇯🇵 · Yaxuan Wen🇯🇵

   We investigate cosmic strings arising from a hierarchical gauge symmetry breaking sequence, $\mathrm{SU}(2)\times \mathrm{U}(1)\to \mathrm{U}(1)\times \mathrm{U}(1)\to \mathrm{U}(1{)}^{\prime }\to \text{Nothing}$. This pattern gives rise to two distinct classes of cosmic strings: light, stable strings formed at a later stage, and heavy, metastable strings originating from an earlier stage. Our focus is on the heavy strings, which may decay either before or after the final $\mathrm{U}(1{)}^{\prime }$ symmetry is broken. We analyze the internal structure of these strings and the magnetic flux sourced by monopole-like configurations that emerge at the endpoints of metastable string segments following their decay. Understanding the nature of the magnetic $\mathrm{U}(1)$ fluxes associated with these monopole-like objects is crucial for studying the post-decay evolution of the string network. The post-decay evolution influences the resulting gravitational wave signals. We show that the magnetic flux carried by string segments can be either confined or unconfined, depending on the specific sequence of symmetry breaking and string decay.

   hep-phhep-thJHEP(2026)·6 citations
8. 08*

   J/$\psi$ and ${\rm Y}$(1S) production in jets at LHC energies

   Lizardo Valencia Palomo🇲🇽

   Quarkonia production in hadronic collisions is far from being understood as none of the existing models can correctly describe the wealth of available data. In particular, LHCb and CMS experiments have reported that PYTHIA 8 cannot reproduce the prompt J/$\psi$ production in jets in proton-proton collisions at two different center of mass energies: the event generator predicts an important amount of the prompt J/$\psi$ to be produced isolated, opposite to the experimental data. This document demonstrates that such effect remains true even if the QCD color reconnection (CR) model is used. Besides that, it is shown that using the new quarkonia parton shower included in PYTHIA 8.312 it is possible to correctly describe the experimental results. This agreement between data and simulation is improved when using the QCD color reconnection approach, opening the possibility to distinguish between the two CR implementations. Finally, a prediction performed for ${\rm Y}$(1S) indicates that a higher jet p${}_T$ selection should be used by the LHC experiments in order to distinguish between PYTHIA 8 results generated with and without the quarkonia parton shower.

   hep-phEur.Phys.J.Plus(2025)·3 citations
9. 09*

   TauSpinner algorithms for including spin and New Physics effects in $\gamma \gamma \to \tau \tau$ process

   A.Yu. Korchin🇺🇦 · E. Richter-Was🇵🇱 · Z. Was🇵🇱

   The possible anomalous New Physics contributions to electric and magnetic dipole moments of the $\tau$ lepton has brought renewed interest in development of new charge-parity violating signatures in the $\tau$-pair production at Belle II energies, and also at higher energies of the LHC and the FCC. In this paper, we discuss effects of anomalous contributions to cross-section and spin correlations in the $\gamma \gamma \to {\tau }^{-}{\tau }^{+}$ production processes, with $\tau$ decays included. Such processes have been observed in the $pp$ and PbPb collisions at CERN LHC experiments. Because of complex nature of the resulting distributions, Monte Carlo techniques are useful, in particular of event reweighting with studied New Physics phenomena. For the $\gamma \gamma$ processes, extensions of the Standard Model amplitudes are implemented in the TauSpinner program. This is mainly with electric and magnetic dipole moments in mind, but algorithm can be easily extended to other New Physics interactions, provided they can be encapsulated into similar form-factors in the Standard Model structure of matrix elements. Basic formulas and algorithm principles are presented, numerical examples are provided as illustration. Information on how to use the program is given in Appendix of the paper.

   hep-phActa Phys.Polon.B(2025)·4 citations
10. 10*

    Linearly Polarized Photon Fusion as a Precision Probe of the Tau Lepton Dipole Moments at Lepton Colliders

    Ding Yu Shao🇨🇳 · Hao Xiang🇨🇳 · Fang Xu🇺🇸 · Bin Yan🇨🇳 · Cheng Zhang🇨🇳

    We present a comprehensive investigation into the anomalous magnetic dipole moment ($a_{\tau }$) and electric dipole moment ($d_{\tau }$) of the $\tau$ lepton using the $\gamma \gamma \to {\tau }^{+}{\tau }^{-}$ process at future lepton colliders, with the Super Tau-Charm Facility serving as a benchmark. By employing transverse-momentum-dependent factorization, we introduce novel observables derived from $\cos 2\varphi$, $\sin 2\varphi$, and $\cos 4\varphi$ azimuthal asymmetries to precisely probe the $\tau$ lepton's electromagnetic structure. Our analysis significantly enhances the precision of $a_{\tau }$ constraints within the photon-photon fusion process, yielding $\mathrm{Re}(a_{\tau })\in [-4.6,7.0]\times 10^{-3}$ at the $2\sigma$ confidence level, which approaches the precision of the Standard Model prediction. These findings highlight the considerable potential of azimuthal asymmetry measurements for high-precision determinations of fundamental particle properties at future lepton colliders.

    hep-phhep-exPRD(2026)·6 citations
11. 11*

    New Physics Opportunities at Neutrino Facilities: BSM Physics at Accelerator, Atmospheric, and Reactor Neutrino Experiments

    Koun Choi🇰🇷 · Doojin Kim🇺🇸 · Jong-Chul Park🇰🇷 · Seodong Shin🇰🇷 · Pouya Bakhti🇰🇷 · Ki-Young Choi🇰🇷 · Chang Hyon Ha🇰🇷 · Kazumi Hata🇯🇵 · Wooyoung Jang🇺🇸 · Yu Seon Jeong🇰🇷 · Young Ju Ko🇰🇷 · Hyun Su Lee🇰🇷 and 13 other authors

    Since the discovery of the Higgs boson, the long-standing task at hand in particle physics is the search for new physics beyond the Standard Model, which accounts for only about 5\% of the Universe. In light of this situation, the neutrino sector has drawn significant attention due to neutrino oscillations, which require physics beyond the Standard Model and have prompted a wide array of active and planned experimental programs. Notably, neutrino facilities offer substantial potential to search for new physics beyond neutrino oscillations, owing to their precision measurement capabilities, diverse experimental configurations, and various neutrino sources. This white paper summarizes the landscape of new physics that can be probed at current and future neutrino experiments, categorized into laboratory-produced and cosmogenic signals. We discuss recent experimental results interpreted through the lens of new physics, as well as detailed plans and projected sensitivities of next-generation facilities. This summary is based on presentations from the 4th Workshop on New Physics Opportunities in Neutrino Facilities (NPN 2024), held at IBS in Daejeon, Korea, on June 3-5, 2024. Particular emphasis is placed on accelerator-based neutrino experiments and a range of neutrino programs in East Asia. We also outline key tasks necessary to realize the promising new physics opportunities ahead.

    hep-phhep-exRept.Prog.Phys.(2026)·6 citations
12. 12*

    Effects of a Brueckner-Hartree-Fock-corrected effective mass on speed of sound, conformality, and observables of dark matter-admixed neutron stars

    Arijit Das🇮🇳 · Prashanth Jaikumar🇺🇸 · Adarsh Karekkat🇮🇳 · Tanumoy Mandal🇮🇳

    We construct an equation of state describing cold and dense matter in the core of neutron stars which includes an admixture of fermionic dark matter and incorporates nucleon effective masses derived from the relativistic Brueckner-Hartree-Fock (BHF) many-body approach within a relativistic mean-field model. Such a BHF-informed mixed-model approach increases stellar compactness, with mass-radius configurations which are consistent with smaller, lighter pulsars. The model displays the expected non-monotonic behavior of sound speed hinted at by neutron star data, and is closer to the conformal bound at maximum mass. We find that the model displays tension with bounds on heavier pulsars, suggesting that the hypothesis of an aggregated dark component in neutron stars needs further critical study.

    hep-phhep-thnucl-thPRC(2025)·2 citations
13. 13*

    Three loop master integrals for $\mathcal{O}(\alpha {\alpha }_s^2)$ corrections to quark form factor

    Tanmoy Pati🇮🇳 · Narayan Rana🇮🇳

    We consider the three-loop mixed strong-electroweak ($\mathcal{O}(\alpha {\alpha }_s^2)$) corrections to the quark form factor. We compute the master integrals which are appearing in the Feynman diagrams containing a single massive boson in the loop. We use the state-of-the-art method of differential equations to compute all 303 of them, expressing the results in terms of generalized polylogarithms. We encounter multiple square roots that cannot be simultaneously rationalized using a single transformation. Applying concurrent transformations allows us to express the results through generalized polylogarithms with a simple alphabet, but with multiple interdependent arguments.

    hep-phhep-thJHEP(2025)·3 citations
14. 14*

    Electromagnetic probes revealing the inner structure of the ${\Lambda }_c(2940)$

    Ping Chen🇨🇳 · Zi-Le Zhang🇨🇳 · Yu Zhuge🇨🇳

    The ${\Lambda }_c(2940)$, an open-charm baryon discovered in 2006, has sparked interest due to its ``low mass puzzle'', paralleling the $X(3872)$ in the charmoniumlike sector. Both states challenge conventional hadronic interpretations, with the $X(3872)$ understood as a $D^{\ast }\bar{D}$ molecular state and the ${\Lambda }_c(2940)$ hypothesized as a $D^{\ast }N$ molecular state. This work investigates the radiative decay modes ${\Lambda }_c(2940)\to {\Lambda }_c(2286)\gamma$, ${\Lambda }_c(2940)\to {\Lambda }_c(2595)\gamma$, and ${\Lambda }_c(2940)\to {\Lambda }_c(2765)\gamma$, analogous to radiative transitions observed in the $X(3872)$. Using the one-boson-exchange model to obtain the $D^{\ast }N$ molecular spatial wave function as input, we calculate decay widths and their ratios, finding differences with different quantum number assumptions. Our findings underscore the potential of electromagnetic probes in revealing its nature and highlight the need for dedicated experimental studies to validate these theoretical predictions.

    hep-phhep-exPRD(2025)·0 citations
15. 15*

    Neutrino Portal to Extra Dimensions: Unified Origin of Dark Radiation, Dark Matter, and Neutrino Decay

    Arnab Chaudhuri🇯🇵

    We propose a unified framework based on sterile neutrinos propagating in large extra dimensions (LED) and coupled to a pseudo-Nambu-Goldstone boson (Majoron) arising from spontaneous lepton number violation. In this setup, the lightest Kaluza-Klein (KK) sterile neutrino serves as warm dark matter, higher KK modes decay invisibly producing a relativistic Majoron contributing to the effective number of neutrino species (Delta Neff), and active neutrinos undergo invisible decay. This model addresses dark radiation, dark matter, and neutrino anomalies within a minimal, testable framework. We present the Boltzmann evolution of relevant species, identify the viable parameter space, and highlight implications for CMB-S4, Lyman-alpha, and neutrino observatories.

    hep-ph0 citations
16. 16*

    Thermodynamical uncertainties for primordial black holes from cosmological phase transitions

    Maciej Kierkla🇵🇱 · Nicklas Ramberg🇮🇹 · Philipp Schicho🇨🇭 · Daniel Schmitt🇩🇪

    Strongly supercooled first-order phase transitions have been proposed as a primordial black hole (PBH) production mechanism. While previous works rely on simplified models with limited thermodynamic precision, we stress that reliable theoretical PBH predictions require precise nucleation dynamics within realistic extensions of the Standard Model. By employing high-temperature dimensional reduction and computing the one-loop fluctuation determinants, we provide a state-of-the-art thermodynamic analysis and obtain an universal lower bound on the transition timescale, $\beta /H_{\ast }\simeq 5$. Then, we estimate the corresponding PBH abundance for classically conformal gauge-Higgs theories. Accounting for constraints from successful percolation and QCD chiral symmetry breaking, the parameter space where PBHs are viable dark matter candidates is severely limited.

    hep-phastro-ph.COPRD(2026)·32 citations
17. 17*

    Charm physics

    David Friday🇬🇧 · Evelina Gersabeck🇩🇪 · Alexander Lenz🇩🇪 · Maria Laura Piscopo🇳🇱

    50 years after the discovery of the first charmed particle, charm physics continues to be an extremely lively field of research and a cornerstone in particle physics. The study of charm, with its unique properties, is characterised by many challenging but also exciting peculiarities, making it an ideal testing ground for Standard Model (SM) predictions and a very sensitive probe of new physics. This chapter is intended to provide a pedagogical introduction to the physics of the charm quark and to its current theoretical and experimental status. Specifically, it discusses the main features of the charm sector of the SM, the theoretical and experimental challenges that arise when dealing with the charm quark, and the methods used to study it. An overview, both from a theoretical and experimental perspective, of fundamental observables such as lifetimes of charm hadrons, $D^0$-meson mixing, charm charge-parity violation (CPV) and rare charm decays is also presented.

    hep-ph14 citations
18. 18*

    A covariant description of the interactions of axion-like particles and hadrons

    Reuven Balkin🇺🇸 · Ta'el Coren🇮🇱 · Yotam Soreq🇮🇱 · Mike Williams🇺🇸

    We present a covariant framework for analyzing the interactions and decay rates of axion-like particles (ALPs) that couple to both gluons and quarks. We identify combinations of couplings that are invariant under quark-field redefinitions, and use them to obtain physical expressions for the prominent decay rates of such ALPs, which are compared with previous calculations for scenarios where ALPs couple exclusively to quarks or to gluons. Our framework can be used to obtain ALP decay rates for arbitrary ALP couplings to gluons and quarks across a broad range of ALP masses.

    hep-phhep-exJHEP(2026)·13 citations
19. 19*

    Supernova-Boosted Dark Matter at Large-Volume Neutrino Detectors

    Badal Bhalla🇺🇸 · Fazlollah Hajkarim🇺🇸 · Doojin Kim🇺🇸 · Kuver Sinha🇺🇸

    Core-collapse supernovae, among the universe's most energetic events, offer a novel window into the dark sector by potentially producing a flux of boosted dark matter (BDM). We explore the potential to detect the BDM produced by supernovae with a focus on fermionic dark matter that interacts with the visible sector through a dark gauge boson. We consider the expected BDM flux at Earth, originating from both the diffuse background of all galactic supernovae and potentially strong signals from individual nearby events. Focusing on BDM-electron scattering, we project the sensitivity of major current and future large-volume neutrino detectors - DUNE, Hyper-Kamiokande, and JUNO - to this elusive signal. Our results indicate that these experiments can significantly constrain or discover BDM within compelling parameter spaces, with sensitivity notably enhanced during nearby supernova occurrences. We further emphasize the unique multi-messenger opportunity presented by a galactic supernova, where the characteristic time delay between the neutrino burst and the BDM signal arrival could provide powerful evidence and enable probes of dark matter properties.

    hep-ph8 citations
20. 20*

    Observing Leptogenesis in Action with Gravitational Waves

    Hitoshi Murayama🇺🇸 · Bea Noether🇺🇸 · Jan Schütte-Engel🇺🇸

    Leptogenesis is arguably the best motivated theory of baryogenesis given the discovery of finite neutrino masses, yet its experimental test is elusive given its high energy scale. We discuss gravitational waves (GWs) produced via graviton bremsstrahlung in right-handed neutrino decays during leptogenesis. The presence of right-handed neutrinos in the early universe can lead to a period of early matter domination. In this context, the resultant GW spectrum scales quadratically with the right-handed neutrino mass, while its peak frequency scales inversely with the Yukawa coupling. Detecting such a spectrum would provide strong evidence for leptogenesis and the existence of heavy right-handed neutrinos. We also discuss how the GW spectrum emitted from the thermal plasma is altered by an era of early matter domination. We show that it can mimic the effects of additional relativistic degrees of freedom and a higher reheating temperature, and that information from the graviton bremsstrahlung GW spectrum can break this degeneracy.

    hep-phgr-qchep-exJCAP(2025)·13 citations
21. 21*

    Decoupling Neutrino Magnetic Moment from Mass with $SU(2{)}_L$ Invariance

    Julie Pagès🇺🇸 · Anil Thapa🇺🇸

    Standard Model extensions that yield observable neutrino magnetic moments typically also induce large neutrino masses, incompatible with experimental limits. This tension motivates the search for mechanisms that naturally decouple magnetic moments from mass generation without requiring fine-tuning. In this letter, we propose a novel mechanism for generating Dirac and Majorana neutrino magnetic moment, in which the associated mass contribution is forbidden by $SU(2{)}_L$ invariance. By carefully selecting the $SU(2{)}_L$ representations connecting the neutrino to the loop diagram, we ensure that only the effective dipole operator involving the non-Abelian part of the photon -- the neutral $SU(2{)}_L$ gauge boson -- is generated. Crucially, the corresponding mass diagram, obtained by removing the external gauge boson leg, vanishes. We provide explicit UV completions that implement this mechanism and yield neutrino magnetic moments within the sensitivity of current and future experiments.

    hep-phEPJC(2026)·3 citations
22. 22*

    Can weak-gravity, causality-violation arguments constrain modified gravity?

    Stephon Alexander🇺🇸 · Heliudson Bernardo🇺🇸 · Nicolás Yunes🇺🇸

    We investigate limitations of causality arguments from flat-spacetime amplitudes, based on the eikonal limit of gravitational scattering, to place constraints on modified gravity. We show that causality constraints are only valid in the weak-gravity regime even for transplanckian scattering, and that such constraints are much less stringent than astrophysical ones, obtained for example from gravitational waves emitted in black hole coalescence. Special attention is given to the weakness of causality constraints on dynamical Chern-Simons gravity, but our results apply to other modified gravity theories as well. In the context of that theory, we also discuss how to obtain a time-delay formula from black hole, neutron stars, and shockwave solutions. For scattering with compact objects, we explicitly show that time delays are greatly suppressed by the ratio of the object's mass to the impact parameter, so time advances only occur greatly outside the cut off of the theory. For the shockwave solution, we find that the time delay is always positive within the regime of validity of the solution. We also comment on the impact of graviton nonlinearities for time-delay calculations in the nonlinear, strong gravity regime. We conclude that amplitude-based causality constraints on modified gravity are typically not stringent relative to other experimental and observational bounds.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2025)·6 citations
23. 23*

    Optimal alignment of Lorentz orientation and generalization to matrix Lie groups

    Congzhou M Sha🇺🇸

    There exist elegant methods of aligning point clouds in ${\mathbb{R}}^3$. Unfortunately, these methods fail to generalize to the case of Minkowski space, as we will show. Instead, we propose two solutions to the following problem: given inertial reference frames $A$ and $B$, and given (possibly noisy) measurements of a set of 4-vectors $\{v_i\}$ made in those reference frames with components $\{v_{A,i}\}$ and $\{v_{B,i}\}$, find the optimal Lorentz transformation $\Lambda$ such that $\Lambda v_{A,i}=v_{B,i}$. The first method is direct least squares optimization through a parametrization of $SO(3,1{)}_{+}$ in terms of the familiar boost and rotation vectors. The second method takes a detour through the Lorentz algebra; in addition to being conceptually simple and possessing a computational advantage over the first method, it can easily be generalized to the alignment of vector representations in other matrix Lie groups.

    ↳ math.NAcs.NAhep-phmath-ph+3J.Comput.Appl.Math.(2026)·1 citation
24. 24*

    Bosonic Spin-1 SOPHY

    Armando De la C. Rangel-Pantoja🇲🇽 · I. Díaz-Saldaña🇲🇽 · Carlos A. Vaquera-Araujo🇲🇽

    In this work we study the canonical quantization of a second-order pseudo-Hermitian field theory for massive spin-1 bosons transforming under the $(1,0)\oplus (0,1)$ representation of the restricted Lorentz Group and satisfying the Klein-Gordon equation.

    ↳ hep-thhep-phPLB(2026)·1 citation
25. 25*

    Manifestation of quark effects in nuclei via bremsstrahlung analysis in the proton-nucleus scattering

    Sergei P. Maydanyuk (1 and 2)🇨🇳 · K. Tsushima (3)🇧🇷 · G. Ramalho (4)🇰🇷 · Peng-Ming Zhang (5) ((1) Southern Center for Nuclear-Science Theory (SCNT), Institute of Modern Physics, Chinese Academy of Sciences, Huizhou, China, (2) Institute for Nuclear Research, National Academy of Sciences of Ukraine, Kyiv, 03680, Ukraine, (3) Laboratório de Física Teórica e Computacional - LFTC, Programa de Pósgraduação em Astrofísica e Física Computacional, Universidade Cidade de São Paulo, 01506-000 São Paulo, São Paulo, Brazil, (4) Department of Physics and OMEG Institute, Soongsil University, Seoul, Republic of Korea, (5) School of Physics and Astronomy, Sun Yat-Sen University, Zhuhai, China)🇨🇳

    \textbf{Background} (1) The incoherent emission of photons is dominant comparing to coherent one in proton-nucleus scattering. The incoherent bremsstrahlung is very sensitive to the magnetic moments of nucleons in nuclei. (2) According to the quark-meson coupling (QMC) model, the nucleon magnetic moments in nuclei are enhanced relative to those in vacuum, originating from the quark structure of nucleons. \textbf{Purpose} Investigate possibilities of observing quark effects in nuclei by the analysis of bremsstrahlung in nuclear reactions. \textbf{Methods} Analyse the bremsstrahlung cross sections with established model in proton-nucleus scattering, by extending with inclusion of in-medium modified nucleon magnetic moments in nuclei by the QMC model. \textbf{Results} (1) After calibrating the model without the quark effects for experimental data (TAPS Collaboration data for $p+\text{isotope}[197]Au$), we calculate the cross sections and observe the slight difference between the spectra for models with and without quark effects. Such result is found for the first time, confirming possibilities of observing the quark effects in the spectra of bremsstrahlung. (2) As found, quark effects are not enough to be observed in middle and heavy nuclei, as they have dominant incoherent contributions. (3) \isotope[18]{C} has minimal incoherent contribution concerning other carbon isotopes, where the quark effects should be minimal. In ratios between the spectra for \isotope[18]{C} and \isotope[12]{C} with and without the quark effects the difference is clearly observed. \textbf{Conclusions} We establish the new physical observable for the quark effects in nuclei in the bremsstrahlung accompanied in the nuclear reactions, which can be measured. The present suggestion is for the first time in both theoretically and experimentally to study the quark effects in nuclei via the bremsstrahlung.

    ↳ nucl-thhep-phnucl-exPLB(2026)·2 citations
26. 26*

    Naive parton picture for kaon color transparency in $A(e,e^{\prime }{K}^{+})$

    Kook-Jin Kong🇰🇷 · Tae Keun Choi🇰🇷 · Byung-Geel Yu🇰🇷

    Nuclear transparency in the electronuclear reaction $A(e,e^{\prime }{K}^{+})$ is investigated in parallel with our previous study of pion transparency in Phys.\ Rev.\ C {\bf 111}, 064608 (2025). Based on an extended Glauber framework that incorporates shadowing from the initial-state two-step process, kaon color transparency (CT) is analyzed to show that the steeper $Q^2$ dependence observed for kaon CT, compared with the pion case, is more naturally described by the naive parton model (NPM) than by the quantum diffusion model (QDM). The inclusion of initial-state shadowing further reduces the transparency and improves the agreement with the experimental data. The $Q^2$ and $A$ dependences of the kaon transparency are presented up to $Q^2=10$~GeV${}^2/c^2$, together with the corresponding $\alpha (Q^2)$ and the supplementary ratio $T_A/T_C$, for comparison with the Jefferson Lab (JLab) data obtained with the 6-GeV electron beam on ${}^{12}$C, ${}^{63}$Cu, and ${}^{197}$Au nuclei.

    ↳ nucl-thhep-phCPC(2026)·2 citations
27. 27*

    Entanglement through high-energy scattering in noncommutative quantum electrodynamics

    Carmelo P. Martin🇪🇸

    We analyze the tree-level generation of entanglement through some key scattering processes in massless quantum electrodynamics on canonical noncomutative spacetime with space-space type of noncommutativity. The fermions in the noncommutative theory will be zero charge fermions. The scattering processes we shall study do not occur in ordinary Minkowski spacetime. We shall use the concurrence to characterize the amount of entanglement generated through a given scattering process. We shall show that, at tree-level, the concurrence for the scattering of two photons of opposite helicity is given by the same expression as in the case of the scattering of gluons in ordinary Minkowski spacetime. Thus, maximal entanglement is achieved if and only if the polar scattering angle is equal to $\pi /2$. We also compute the concurrence for the head-on collision in the laboratory reference frame of two fermions of opposite helicity to obtain the same result as in the case of photon scattering. Finally, we shall study a type of collision at right angles in the laboratory frame of fermions with opposite helicity. We show that in the latter case the concurrence depends on energy of the incoming fermions, the noncommutativity matrix ${\theta }^{ij}$, the polar, $\theta$, and azimuth angle, $\varphi$, of the zero-momentum frame of the incoming fermions. In this latter case we see that when $\theta =\pi /2$ there are values of $\varphi$ for which no entanglement is generated.

    ↳ hep-thhep-phquant-phEPJC(2026)·6 citations
28. 28*

    ECFA Higgs, electroweak, and top Factory Study

    H. Abidi · J.A. Aguilar-Saavedra · S. Airen · S. Ajmal · M. Al-Thakeel · G.L. Alberghi · J. Alcaraz Maestre · J. Alimena · S. Alshamaily · J. Altmann · W. Altmannshofer · Y. Amhis and 365 other authors

    The ECFA Higgs, electroweak, and top Factory Study ran between 2021 and 2025 as a broad effort across the experimental and theoretical particle physics communities, bringing together participants from many different proposed future collider projects. Activities across three main working groups advanced the joint development of tools and analysis techniques, fostered new considerations of detector design and optimisation, and led to a new set of studies resulting in improved projected sensitivities across a wide physics programme. This report demonstrates the significant expansion in the state-of-the-art understanding of the physics potential of future e+e- Higgs, electroweak, and top factories, and has been submitted as input to the 2025 European Strategy for Particle Physics Update.

    ↳ hep-exhep-phCERN Yellow Rep.Monogr.(2025)·61 citations
29. 29*

    What new physics can we extract from inflation using the ACT DR6 and DESI DR2 Observations?

    Sayantan Choudhury🇵🇱 · Gulnur Bauyrzhan🇰🇿 · Swapnil Kumar Singh🇮🇳 · Koblandy Yerzhanov🇰🇿

    We present a comprehensive analysis of inflationary models in light of projected sensitivities from forthcoming CMB and gravitational wave experiments, incorporating data from recent ACT DR6, DESI DR2, CMB-S4, LiteBIRD, and SPHEREx. Focusing on precise predictions in the $(n_s,{\alpha }_s,{\beta }_s)$ parameter space, we evaluate a broad class of inflationary scenarios -- including canonical single-field models, non-minimally coupled theories, and string-inspired constructions such as Starobinsky, Higgs, Hilltop, $\alpha$-attractors, and D-brane models. Our results show that next-generation observations will sharply constrain the scale dependence of the scalar power spectrum, elevating ${\alpha }_s$ and ${\beta }_s$ as key discriminants between large-field and small-field dynamics. Strikingly, several widely studied models -- such as quartic Hilltop inflation and specific DBI variants -- are forecast to be excluded at high significance. We further demonstrate that the combined measurement of ${\beta }_s$ and the field excursion $\Delta \varphi$ offers a novel diagnostic of kinetic structure and UV sensitivity. These findings underscore the power of upcoming precision cosmology to probe the microphysical origin of inflation and decisively test broad classes of theoretical models.

    ↳ astro-ph.COgr-qchep-phhep-thJHEAp(2026)·41 citations
30. 30*

    Emergence of cosmic structure from Planckian discreteness

    Gabriel R. Bengochea🇦🇷 · Gabriel Leon🇦🇷 · Alejandro Perez🇫🇷

    In the standard inflationary paradigm the inhomogeneities observed in the CMB arise from quantum fluctuations of an initially homogeneous and isotropic vacuum state. This picture suffers from two well-known weaknesses. First, it assumes that quantum field theory remains valid at trans-Planckian scales, without modifications from quantum gravity. Second, it necessitates a quantum-to-classical transition in which fluctuations of a homogeneous quantum state become the classical inhomogeneities seen in the CMB. Recently, an alternative paradigm has been proposed in which such inhomogeneities are present from the very beginning, emerging from the assumed discreteness of spacetime at the Planck scale predicted by certain approaches to quantum gravity. Within this framework, scale-invariant scalar perturbations are generated naturally, without relying on trans-Planckian assumptions or invoking a quantum-to-classical transition. Specifically, inhomogeneities in the quantum state at the Planck scale propagate into semiclassical inhomogeneities on CMB scales. Here, we extend the aforementioned proposal to the most realistic case of a quasi-de Sitter expansion; in particular, we compute the scalar perturbation spectrum as a function of the slow-roll parameters, systematically encoded through the Hubble flow functions.

    ↳ gr-qchep-phhep-thquant-ph1 citation
31. 31*

    $\mu$LHC: Antimuon Ring and HL-LHC based ${\mu }^{+}p$ Collider

    D. Akturk🇹🇷 · A. C. Canbay🇹🇷 · H. Dagistanli🇹🇷 · B. Dagli🇹🇷 · U. Kaya🇹🇷 · B. Ketenoglu🇹🇷 · A. Kilic🇹🇷 · F. Kocak🇹🇷 · A. Ozturk🇹🇷 · S. Sultansoy🇹🇷 · I. Tapan🇹🇷 · F. Zimmermann🇨🇭

    Conceptual design and performance evaluation of HL-LHC based antimuon-proton collider ($\mu$LHC) are presented. Leveraging the $\mu$TRISTAN concept based on established J-PARC ultra-cold ${\mu }^{+}$ beam technology, $\mu$LHC will give the opportunity to achieve a 5.3 TeV center-of-mass energy, significantly surpassing EIC and LHeC. Two booster ring options for ${\mu }^{+}$ acceleration, namely, a $\mu$TRISTAN-based and a repurposed LHeC ERL-based systems, are explored. Achievable luminosities are predicted to exceed $10^{33}c{m}^{-2}{s}^{-1}$. The $\mu$LHC offers substantially wider kinematic plane coverage, particularly in small-x and high-$Q^2$ regions, significantly contributing to QCD basics and Higgs boson properties. Its unique potential for BSM physics extends to muon-related phenomena like excited muons, color-octet muons, leptoquarks, and contact interactions. A possible detector concept is also outlined. Given the maturity of ultra-cold ${\mu }^{+}$ beam technology, $\mu$LHC is highly feasible for earlier realization than the muon collider, positioning it as a critical tool for the future of high energy physics.

    ↳ physics.acc-phhep-exhep-phPTEP(2026)·3 citations
32. 32*

    Confined-deconfined interface tension and latent heat in SU(N) gauge theory

    Tobias Rindlisbacher🇫🇮 · Kari Rummukainen🇫🇮 · Ahmed Salami🇫🇮

    We present high-precision lattice results for the confined-deconfined interface tension and the latent heat of pure SU($N$) gauge theories up to $N=10$ and investigate their asymptotic $N$-dependency. For both quantities we observe the leading $N^2$ behaviour and subleading corrections, with the result for the interface tension $\sigma /T_c^3=0.0182(7)N^2-0.194(15)$ and for the latent heat $L/T_c^4=0.360(6)N^2-1.88(17)$. We use the \emph{mixed phase ensemble} method - where the system is constrained so that half of the volume is in the confined phase and the other half in the deconfined phase - and the interface tension is obtained by measuring the capillary wave fluctuation spectra of the interfaces between the two phases. The method bypasses supercritical slowing down from which other methods for determining the interface tension suffer, and as a by-product produces accurate estimates of the critical inverse gauge coupling as a function of the inverse temperature. We use the latter to determine the lattice beta function values, required to compute the latent heat from the discontinuity in the average plaquette action across the confined-deconfined transition.

    ↳ hep-lathep-phPRD(2025)·8 citations
33. 33*

    Soft Factorisation and Exponentiation from Schwinger-Space Geometry

    Carolina Figueiredo🇺🇸 · Giulio Gambuti🇬🇧 · Holmfridur S. Hannesdottir🇺🇸

    Infrared divergences in Quantum Field Theory govern the low-energy dynamics of many physical theories, and their understanding is a crucial ingredient in predicting the outcomes of collider experiments. We present a novel approach to deriving the structure of these divergences by employing the Schwinger parametrization of Feynman integrals. After using tropical geometry to identify divergent limits, we study the all-orders asymptotic properties of Feynman diagrams via matrix manipulations of graph Laplacians, which allows us to analyse their IR behaviour systematically. We explicitly demonstrate the soft-hard factorization of the integrand for a broad class of diagrams, and reveal that when written in terms of "worldline distances", topologically distinct diagrams asymptote to the same integrand. In particular, for the case of Quantum Electrodynamics, we use this fact to show how ladder-type diagrams combine in Schwinger-parameter space to yield the correct exponentiated soft anomalous dimension. This framework provides a foundation for extending these methods to more complex theories like Quantum Chromodynamics and offers a pathway towards a systematic understanding of infrared divergences in perturbative amplitudes.

    ↳ hep-thhep-phJHEP(2026)·2 citations
34. 34*

    How to Count States in Gravity

    Vijay Balasubramanian🇺🇸 · Tom Yildirim🇬🇧

    Gibbons and Hawking proposed that the Euclidean gravity path integral with periodic boundary conditions in time computes the thermal partition sum of gravity. As a corollary, they argued that a derivative of the associated free energy with respect to the Euclidean time period computes gravitational entropy. Why is this interpretation correct? That is, why does this path integral compute a trace over the Hilbert space? Here, we show that the quantity computed by the Gibbons-Hawking path integral is equal to an {\it a priori} different object -- an explicit thermal trace over the Hilbert space spanned by states produced by the Euclidean gravity path integral. This follows in two ways: (a) if the Hilbert space with two boundaries factorizes into a product of two single boundary Hilbert spaces, as we have previously shown; and (b) via explicit resolution of the trace by a spanning basis of states. We similarly show how a replicated Euclidean gravity path integral with a single periodic boundary computes a Hilbert space trace of powers of the density matrix, explaining why this approach computes the entropy of states entangled between two universes.

    ↳ hep-thgr-qchep-phPRD(2026)·18 citations
35. 35*

    Cancellation of one-loop correction to soft tensor power spectrum

    Yohei Ema🇨🇭 · Muzi Hong🇯🇵 · Ryusuke Jinno🇯🇵 · Kyohei Mukaida🇯🇵

    We demonstrate that there are no scale-invariant one-loop corrections to the superhorizon tensor perturbations from small-scale (potentially enhanced) scalar perturbations, irrespective of the details of inflationary background time evolution. For this purpose we derive a soft tensor effective field theory at leading order in the gradient expansion by integrating out small-scale scalar fluctuations in a general time-dependent background over the Schwinger-Keldysh contour, i.e., we perform loop calculations in the soft limit of external momentum. The absence of scale-invariant corrections originates from the diffeomorphism invariance of general relativity and is therefore unavoidable.

    ↳ astro-ph.COhep-phhep-thJCAP(2026)·10 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.