Wed·Jun 11, 2025Wednesday·June 11, 2025

1. 01*

   Unraveling Freeze-in Dark matter through the echoes of gravitational waves

   Partha Konar🇮🇳 · Sudipta Show🇮🇳

   In the quest to unravel the dark sector, feebly interacting freeze-in dark matter presents an intriguing possibility, plausibly explaining the consistent null results from various dark matter experiments. We propose a unique imprint in the form of gravitational waves generated during the freeze-in production of dark matter from heavy particle decay in the early universe. This characteristic gravitational wave signature can serve as a powerful probe for freeze-in dark matter. Our study indicates that future high-frequency gravitational wave experiments can detect these waves, offering a novel avenue to critically test the underlying conditions and requirements of this dark matter paradigm, which typically lie beyond the reach of current and planned dark matter detection experiments.

   hep-phPRD(2026)·11 citations
2. 02*

   Dark Matter and CP Violation in Some Symmetry-Constrained 3HDMs

   Anton Kunčinas🇵🇹

   Multi-Higgs-doublet models can accommodate a dark matter candidate. An underlying symmetry not only ensures the candidate's stability but also helps control the number of free parameters. We consider two scenarios. First, we explore dark matter candidates in the $S_3$-symmetric three-Higgs-doublet model. Notably, our findings reveal that the cases we discuss allow for different dark matter mass ranges compared to other candidates within three-Higgs-doublet models. Additionally, we investigate an alternative to conventional stabilisation via discrete symmetries by examining stabilisation through continuous symmetries. This alternative approach exhibits a unique characteristic-the emergence of mass-degenerate states. We also explore the impact of CP violation in the $S_3$-symmetric three-Higgs-doublet model. Our analysis investigates how different representations of quarks under the $S_3$ group, combined with various vacuum configurations, lead to distinct phenomenological consequences, including the possibility of very light neutral scalars.

   hep-ph4 citations
3. 03*

   Radiative decays of $P$-wave charmed baryons in the $SU(3)$ flavor $6_{\mathbf{F}}$ representation

   Xuan Luo🇨🇳 · Hua-Xing Chen🇨🇳 · Er-Liang Cui🇨🇳 · Hui-Min Yang🇨🇳 · Dan Zhou🇨🇳 · Zhi-Yong Zhou🇨🇳

   We perform a comprehensive investigation of the radiative decays of $P$-wave charmed baryons in the $SU(3)$ flavor $6_F$ representation, employing the light-cone QCD sum rule approach within the framework of heavy quark effective theory. We analyze their electromagnetic transitions into ground-state charmed baryons via photon emission. When combined with the mass spectra and strong decay properties previously studied in Ref.~\cite{Yang:2021lce}, our results constitute a systematic and complete QCD sum rule analysis of the $P$-wave singly charmed baryons within the framework of heavy quark effective theory. As summarized in Table~\ref{tab:result}, several excited charmed baryons are found to possess suppressed strong decay widths, thereby rendering their radiative decay channels particularly significant for experimental identification and theoretical understanding.

   hep-phPRD(2025)·4 citations
4. 04*

   Reexamining the search for light ALPs at flavor and forward accelerator experiments

   Tong Li🇨🇳 · Michael A. Schmidt🇦🇺 · Man Yuan🇨🇳

   The axion-like particle (ALP) is a well-motivated extension of the Standard Model. In this work, we revisit the sensitivity of forward accelerator experiments to light long-lived ALPs, and analyze flavor constraints. Our analysis incorporates recent measurements of the rare decays $B\to K+X$ and $K\to \pi +X$, which place stringent bounds on quark flavor violation of a light ALP. We consider the complete list of hadronic modes in the calculation of the ALP decay rate and exclusive production channels based on recent improvements. The analysis includes the discussion of tree-level quark flavor-violating couplings in addition to a universal flavor-conserving ALP coupling to fermions and the electroweak ALP couplings. Our results demonstrate the complementarity of heavy meson decays and forward accelerator facilities in probing light ALPs. The interplay between two ALP couplings is also investigated.

   hep-phPRD(2025)·6 citations
5. 05*

   Radiative decay of ${\chi }_{c1}$ states in effective Lagrangian approach

   Thanat Sangkhakrit🇹🇭 · Attaphon Kaewsnod🇹🇭 · Ayut Limphirat🇹🇭 · Khanchai Khosonthongkee🇹🇭 · Warintorn Sreethawong🇹🇭 · Nopmanee Supanam🇹🇭 · Yupeng Yan🇹🇭

   The ${\chi }_{c1}(3872)$ state, first observed by the Belle collaboration with its quantum numbers identified as $J^{PC}=1^{++}$, has been the subject of extensive research due to its intriguing properties. Several theoretical interpretations have been proposed to explain its unique characteristics, including the ${\chi }_{c1}(2P)$ assignment, a molecular ${\bar{D}}^{\ast }D/\bar{D}{D}^{\ast }$ configuration, a coupled-channel framework incorporating $c\bar{c}$ and di-meson degrees of freedom, and the compact tetraquark hypothesis. However, challenges remain in reconciling its mass coincidence with the threshold and the observed isospin violation within both the pure $c\bar{c}$ and compact tetraquark models. In this study, we examine the radiative decays of the ${\chi }_{c1}(1P)$ and ${\chi }_{c1}(3872)$ states in an effective field theory framework, incorporating triangle loops of $D$ and $D^{\ast }$ mesons. The model parameters are calibrated based on the observed branching fraction of the radiative decay mode ${\chi }_{c1}(1P)\to J/\psi \gamma$. Utilizing these fixed parameters, we predict the branching fractions $R_{{\chi }_{c1}(3872)\to J/\psi \gamma }\sim 10^{-1}$ and $R_{{\chi }_{c1}(3872)\to \psi (2S)\gamma }\sim 10^{-2}$, and the relative fraction ${\mathcal{R}}_{\Psi \gamma }\approx 0.109$. The work supports the argument that the ${\chi }_{c1}(3872)$ is unlikely a $c\bar{c}$ state.

   hep-ph0 citations
6. 06*

   An interpretation of the fully-charmed scalar state $X(6200)$ as a molecular di-meson

   Ö. E. Demircan · H. Dağ🇹🇷 · H. Sundu🇹🇷 · J. Y. Süngü🇹🇷 · E. V. Veliev🇹🇷

   The LHCb Collaboration recently observed new structures in the invariant mass spectrum of $J/\psi J/\psi$ meson pairs produced in proton-proton collisions, including a narrow peak around $6.2$ GeV. This study investigates the thermal behavior of this newly discovered fully-charm resonance, assuming it to be an ${\eta }_c{\eta }_c$ molecule with quantum numbers $J^{PC}=0^{++}$. Employing thermal QCD sum rules up to dimension four, we analyze the temperature dependence of the mass and the decay constant. Our results indicate that both physical quantities decrease as the temperature rises. Notably, at zero temperature, the mass and decay constant of the state are consistent with those reported in the existing literature. These findings are expected to provide valuable insights for future experimental investigations in this field.

   hep-ph1 citation
7. 07*

   Axion-like particle constraints from preSN in future experiments

   Federica Giacchino🇮🇹

   We extend the study of the search for ALP-photon emissions from a Supernovae (SNe) progenitor, the Red Supergiant Star (RGS), as Betelgeuse, arising through a combination of Bremsstrahlung, Compton, and Primako? processes, in the hard-X and MeV energy range, using the next proposed and future experiments, such as COMCUBE, GECCO, COSI, AMEGO-X, and e-ASTROGAM.

   hep-phPoS(2025)·0 citations
8. 08*

   $D$ and $D^{\ast }$ mesons in isospin asymmetric nuclear medium

   Anshu Gautam🇮🇳 · Dhananjay Singh🇮🇳 · Navpreet Kaur🇮🇳 · Satyajit Puhan🇮🇳 · Suneel Dutt🇮🇳 · Harleen Dahiya🇮🇳 · Arvind Kumar🇮🇳

   We investigate the properties of pseudoscalar $D$ and vector $D^{\ast }$ mesons in an isospin asymmetric nuclear medium using a hybrid approach that integrates the light-front quark model with the chiral SU(3) quark mean field model. The influence of isospin asymmetric nuclear medium is examined by utilizing the in-medium quark masses derived from the chiral SU(3) quark mean field model as an input in the light-front quark model to study the medium modification of $D$ mesons. We examine the impact of isospin asymmetry and baryon density at zero and finite temperature on the effective masses, weak decay constants, and distribution amplitudes of the pseudoscalar mesons $D^0$, $D^{+}$, $D_s$, and the vector mesons $D^{0\ast }$, $D^{+\ast }$, and $D_s^{\ast }$. Our results indicate significant medium-induced changes for pseudoscalar $D$ and vector $D^{\ast }$ mesons having $u/d$ as one of their constituent quarks, while a comparatively reduced effect is observed for mesons containing a strange quark. In contrast to temperature and isospin asymmetry, changes in the baryon density of the nuclear medium have a larger effect on different properties of $D$ and $D^{\ast }$ mesons.

   hep-phnucl-thPTEP(2025)·1 citation
9. 09*

   Entanglement Suppression, Quantum Statistics and Symmetries in Spin-3/2 Baryon Scatterings

   Tao-Ran Hu🇨🇳 · Katsuyoshi Sone🇯🇵 · Feng-Kun Guo🇨🇳 · Tetsuo Hyodo🇯🇵 · Ian Low🇺🇸

   We explore the interplay among entanglement suppression, quantum statistics and enhanced symmetries in the non-relativistic $S$-wave scattering involving the lowest-lying spin-3/2 baryons, which can be considered as four-dimensional qudits. These baryons form a ten-dimensional representation (decuplet) under the $\text{SU}(3)$ light-flavor symmetry and, in this limit, are considered indistinguishable under strong interactions. Treating the $S$-matrix in the spin-3/2 baryon-baryon scattering as a quantum logic gate in the spin space, we study the consequence of entanglement suppression and compute the entanglement power of the $S$-matrix. When the entanglement power vanishes, the $S$-matrix is either an Identity or a SWAP gate and spin-flavor symmetries and/or non-relativistic conformal invariance emerge, as previously observed in spin-1/2 baryons. In the case of scattering identical particles, the entanglement power never vanishes due to constraints from spin statistics, which we interpret as projection-valued measurements onto symmetric or antisymmetric Hilbert space and define the entanglement power accordingly. When the entanglement power is non-vanishing but sits at a global or local minimum, enhanced symmetries still emerge and the $S$-matrix can be interpreted as an Identity or a SWAP gate acting on the restricted Hilbert space allowed by quantum statistics. In general, when scattering identical spin-$s$ particles, we identify an enhanced $\text{SU}(2s+1{)}_{\text{spin}}$ symmetry for the Identity gate.

   hep-phhep-thnucl-thquant-phPRResearch(2025)·27 citations
10. 10*

    The Highest-Energy Neutrino Event Constrains Dark Matter-Neutrino Interactions

    Toni Bertólez-Martínez🇪🇸 · Gonzalo Herrera🇺🇸 · Pablo Martínez-Miravé🇩🇰 · Jorge Terol Calvo🇮🇹

    Dark Matter-neutrino interactions affect the propagation of astrophysical neutrinos, attenuating the flux of neutrinos arriving at Earth. Using the highest-energy neutrino event detected to date by the KM3NeT collaboration as an example, and assuming an extragalactic origin, we derive limits on these interactions at $E_{\nu }=220_{-110}^{+570}\mathrm{PeV}$. Considering only the propagation on the Milky Way Dark Matter halo, we constrain the interaction cross section over the mass of the Dark Matter candidate to be, ${\sigma }_{\mathrm{DM}-\nu }/m_{\mathrm{DM}}\lesssim 10^{-22}{\mathrm{cm}}^2{\mathrm{GeV}}^{-1}$. If a transient source was positively identified, the high-energy neutrino would have crossed the dark-matter halo of the source host as well, resulting in more stringent constraints (e.g., up to $\sim$ 6 orders of magnitude assuming the blazar PKS 0605-085 is the source). These bounds on the Dark Matter-neutrino interaction cross section are translated into limits on the mass of the Dark Matter candidate, the mass of the mediator, and the coupling strength for different simplified models. We find that the constraints from the KM3-230213A high-energy event for these simplified models are almost entirely ruled out for masses above the MeV by unitarity constraints. Therefore, the attenuation of such energetic neutrinos by Dark Matter calls for richer dark sectors in order to produce meaningful constraints.

    hep-phastro-ph.COastro-ph.HEPRD(2026)·16 citations
11. 11*

    Event generation at MEPS@NLO accuracy in neutral and charged current DIS at the EIC

    Peter Meinzinger🇨🇭 · Daniel Reichelt🇨🇭 · Federico Silvetti🇬🇧

    We present state-of-the-art hadron-level predictions for the deep-inelastic scat- tering process at next-to-leading-order precision for several multiplicities, con- sistently merged in one sample. For the first time at this level of accuracy, we consider both neutral and charged current deep-inelastic scattering at the Electron-Ion Collider, and present the first application of consistent next-to- leading-order merging to charged current deep-inelastic scattering in general. We critically examine inclusive predictions using multileg merging techniques, contrasting perturbative and nonperturbative uncertainties. Further, we study typical kinematic deep-inelastic scattering observables as well as jet measure- ments and 1-jettiness with realistic cuts implied by expected and past detector resolution. On the perturbative side, we see large corrections toward small vir- tualities and Bjorken-x, which can be captured by higher-multiplicity matrix elements and the merging procedure. Nonperturbative effects, while negligible in most jet observables, can reach similar size as the perturbative uncertainties around the peak of the 1-jettiness distributions especially at low values of $Q^2$ .

    hep-phhep-exPRD(2025)·7 citations
12. 12*

    Deconstructing resonant Higgs pair production at the LHC: effects of coloured and neutral scalars in the NMSSM test case

    Stefano Moretti🇬🇧 · Luca Panizzi🇮🇹 · Jörgen Sjölin🇸🇪 · Harri Waltari🇸🇪

    We study resonant production of pairs of Standard Model (SM)-like Higgs bosons, in the presence of new neutral Higgs states together with new coloured scalars (stops or sbottoms) in loops within the Next-to-Minimal Supersymmetric SM (NMSSM). This is used as a test case to prove that the Large Hadron Collider has sensitivity to a variety of effects stemming from interferences between resonant (heavy) Higgs diagrams and/or among these and non-resonant topologies involving loops of both tops and stops. These effects can alter significantly the naive description of individual $s$-channel Breit-Wigner resonances, leading to distortions of the latter which, on the one hand, may mask their presence but, on the other hand, could enable one to extract features of the underlying new physics scenario. This last aspect is made possible through a decomposition of the $gg\to hh$ signal process into all its amplitude components, each of which has a well-defined coupling structure. Ultimately, such effects can be traced back to the relevant Feynman diagrams and can enable a detailed interpretation of this process. To illustrate this, we introduce various Benchmark Points that exhibit potentially observable features during the current and/or upcoming runs of the LHC in one or more of the three customary di-Higgs decay channels: $b\bar{b}b\bar{b}$, $b\bar{b}{\tau }^{+}{\tau }^{-}$ and $b\bar{b}\gamma \gamma$.

    hep-phhep-exPRD(2025)·5 citations
13. 13*

    Equivalence of two component spinor mechanism and four component spinor mechanism in top quark pair production

    Malvika Deo🇮🇳 · Anuradha Misra🇮🇳 · Sharada Subramanian🇮🇳 · Radhika Vinze🇮🇳

    We calculate the $S$-matrix elements for the process $e^{+}{e}^{-}\to t\bar{t}$ mediated by SM photon, $Z$ boson and an additional $Z^{{}^{\prime }}$ boson indicating the contribution from new physics. We calculate the amplitude square using two component spinor formalism and four component spinor formalism and show the equivalance of the results using the two formalisms. We also establish the relations between the couplings of $Z^{{}^{\prime }}$ boson to fermions in the two component spinor formalism and in the four component spinor formalism.

    hep-ph0 citations
14. 14*

    The Primakoff effect: The Axion-Photon Mixing in the Context of Stellar Plasma Physics

    Bernard Teles de Menezes🇧🇷

    We propose in this work the study of the production of axions in stellar plasma medium through an external magnetic field. In the background field approximation, we can show that the presence of the external magnetic field induces a mixing between the photon and the axion, i.e. the so called Primakoff effect. Since the axion is one of the greatest candidates for dark matter, for being a neutral pseudo-scalar field, the Primakoff process constitutes a mechanism (or portal) to access the dark sector, which in turn provides us new perspectives beyond the standard model. In the high energies limit, observables like probabilities transitions and particles production rates were computed.

    hep-phhep-th0 citations
15. 15*

    Energy Correlators: A Journey From Theory to Experiment

    Ian Moult🇺🇸 · Hua Xing Zhu🇨🇳

    Collider experiments offer a unique opportunity to explore the Standard Model (SM), and to search for new physics, new interactions, and new principles of nature. The theoretical abstraction of a collider, namely the study of correlations in asymptotic fluxes, provides one of the most basic examples of an observable in quantum field theory (QFT) and quantum gravity. Energy flux is described in QFT by energy flow operators, a particular example of light-ray operators. In addition to their central role in the theoretical description of collider physics, energy flow operators play an important role in diverse areas of formal QFT and gravity, providing a connection between real world collider phenomenology, and the deep underlying principles of QFT. Recently it has become possible to measure correlation functions of energy flow operators in a wide variety of collider experiments, providing an exciting new connection between collider physics and formal theory. In this review, we provide a survey of recent progress in our understanding of energy operators and their correlators, highlighting their importance in both formal theory and collider phenomenology, and in particular, their great potential for bridging these areas to provide new ways to understand the real world. We intend this article as a resource for both formal theorists interested in understanding how light-ray operators are being applied in particle and nuclear physics, as well as for experimentalists interested in the theoretical motivation for these observables. Most importantly, we aim to stimulate further interaction between the formal, phenomenological and experimental communities through the common lens of energy correlators.

    hep-phhep-exhep-thnucl-ex+1127 citations
16. 16*

    Precision $e^{+}{e}^{-}$ Hemisphere Masses in the Dijet Region with Power Corrections

    Andre H. Hoang🇦🇹 · Vicent Mateu🇪🇸 · Matthew D. Schwartz🇺🇸 · Iain W. Stewart🇺🇸

    We derive high-precision results for the $e^{+}{e}^{-}$ heavy jet mass (HJM) $d\sigma /d\rho$ and dihemisphere mass (DHM) $d^2\sigma /(d{s}_{1}d{s}_2)$ distributions, for $s_1\sim s_2$, in the dijet region. New results include: i) the N${}^3$LL resummation for HJM of large logarithms ${\ln }^n(\rho )$ at small $\rho$ including the exact two-loop non-global hemisphere soft function, the 4-loop cusp anomalous dimension and the 3-loop hard and jet functions, ii) N${}^3$LL results for DHM with resummation of logarithms $\ln (s_{1,2}/Q^2)$ when there is no large separation between $s_1$ and $s_2$, iii) profile functions for HJM to give results simultaneously valid in the peak and tail regions, iv) a complete two-dimensional basis of non-perturbative functions which can be used for double differential observables, that are needed for both HJM and DHM in the peak region, and v) an implementation of renormalon subtractions for large-angle soft radiation to $\mathcal{O}({\alpha }_s^3)$ together with a resummation of the additional large $\ln (Q\rho /{\Lambda }_{QCD})$ logarithms. Here $Q$ is the $e^{+}{e}^{-}$ center-of-mass energy. Our resummation results are combined with known fixed-order $\mathcal{O}({\alpha }_s^3)$ results and we discuss the convergence and remaining perturbative uncertainty in the cross section. We also prove that, at order $1/Q$, the first moment of the HJM distribution involves an additional non-perturbative parameter compared to the power correction that shifts the tail of the spectrum (where $1\gg \rho \gg {\Lambda }_{QCD}/Q$). This differs from thrust where a single non-perturbative parameter at order $1/Q$ describes both the first moment and the tail, and it disfavors models of power corrections employing a single non-perturbative parameter, such as the low-scale effective coupling model. In this paper we focus only on the dijet region, not the far-tail distribution for $\rho \gtrsim 0.2$.

    hep-phJHEP(2025)·12 citations
17. 17*

    Light PIDM in Warped Extra Dimensions

    Mathew T Arun🇮🇳 · Prachiti P. Athalye🇮🇳 · Basabendu Barman🇮🇳

    Traditional Planckian Interacting Dark Matter (PIDM), which interacts exclusively through gravity, typically requires heavy DM candidates (with mass $10^3-10^{15}$ GeV) and very high reheating temperature ($T_{\mathrm{rh}}\gtrsim 10^{15}$ GeV). In this article, we explore a novel realization of PIDM in warped five-dimensions, consisting of an "Ultra Violet"$-$"Dark"$-$"Infra Red" (UV-DB-IR) brane setup, where the DM can be a Dark brane composite light state with mass 1 MeV $-$ 1 TeV. The DM sector is assumed to interact solely via gravity in five-dimensions. After orbifolding and performing a Kaluza-Klein (KK) decomposition, the DM is assumed to be localized onto the DB, which is positioned in the extra-dimension such that the DM interacts with both the massless graviton and its massive KK excitations, with suppressed couplings to remain consistent with the ethos of the PIDM framework. The light (heavy) Standard Model matter is assumed to be localized near UV (IR) branes for the geometric Froggatt-Nielsen mechanism, while their KK modes are localized close to the IR brane. We show that this construction allows for a viable and efficient freeze-in production mechanism for light composite PIDM, consistent with TeV-scale reheating temperature.

    hep-phastro-ph.COhep-thJCAP(2025)·0 citations
18. 18*

    Cosmological Histories in Neutrino Portal Dark Matter

    Amro E. B. Abdelrahim🇺🇸 · Brian Batell🇺🇸 · Joshua Berger🇺🇸 · David McKeen🇨🇦 · Barmak Shams Es Haghi🇺🇸

    We explore the diverse cosmological histories of a dark sector that is connected to the Standard Model (SM) via a Dirac sterile neutrino. The dark sector consists of a complex scalar and a Dirac fermion dark matter (DM) candidate protected by a global $U(1)$ stabilizing symmetry. Assuming the dark sector has negligible initial abundance and is populated from reactions in the SM thermal plasma during the radiation era, we show that the cosmological histories of the dark sector fall into four qualitatively distinct scenarios, each one characterized by the strengths of the portal couplings involving the sterile neutrino mediator. By solving Boltzmann equations, both semi-analytically and numerically, we explore these thermal histories and transitions between them in detail, including the time evolution of the temperature of the dark sector and the number densities of its ingredients. We also discuss how these various histories may be probed by cosmology, direct detection, indirect detection, collider searches, and electroweak precision tests.

    hep-phastro-ph.COJCAP(2026)·4 citations
19. 19*

    Dense Matter in Neutron Stars with eXTP

    Ang Li🇨🇳 · Anna L. Watts🇳🇱 · Guobao Zhang🇨🇳 · Sebastien Guillot🇫🇷 · Yanjun Xu🇨🇳 · Andrea Santangelo🇩🇪 · Silvia Zane🇬🇧 · Hua Feng🇨🇳 · Shuang-Nan Zhang🇨🇳 · Mingyu Ge🇨🇳 · Liqiang Qi🇨🇳 · Tuomo Salmi🇫🇮 and 73 other authors

    In this White Paper, we present the potential of the enhanced X-ray Timing and Polarimetry (eXTP) mission to constrain the equation of state of dense matter in neutron stars, exploring regimes not directly accessible to terrestrial experiments. By observing a diverse population of neutron stars - including isolated objects, X-ray bursters, and accreting systems - eXTP's unique combination of timing, spectroscopy, and polarimetry enables high-precision measurements of compactness, spin, surface temperature, polarimetric signals, and timing irregularity. These multifaceted observations, combined with advances in theoretical modeling, pave the way toward a comprehensive description of the properties and phases of dense matter from the crust to the core of neutron stars. Under development by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Sciences, the eXTP mission is planned to be launched in early 2030.

    ↳ astro-ph.HEastro-ph.SRhep-phnucl-thSCPMA(2025)·49 citations
20. 20*

    Reconstructing Laurent expansion of rational functions using p-adic numbers

    Tianya Xia🇨🇳 · Li Lin Yang🇨🇳

    We propose a novel method for reconstructing Laurent expansion of rational functions using $p$-adic numbers. By evaluating the rational functions in $p$-adic fields rather than finite fields, it is possible to probe the expansion coefficients simultaneously, enabling their reconstruction from a single set of evaluations. Compared with the reconstruction of the full expression, constructing the Laurent expansion to the first few orders significantly reduces the required computational resources. Our method can handle expansions with respect to more than one variables simultaneously. Among possible applications, we anticipate that our method can be used to simplify the integration-by-parts reduction of Feynman integrals in cutting-edge calculations.

    ↳ hep-thhep-phComput.Phys.Commun.(2026)·0 citations
21. 21*

    Behaviour of $\alpha$-attractors in Warm Inflation

    Dibya Chakraborty🇮🇳 · Suratna Das🇮🇳

    The $\alpha$-attractor models of inflation have remained one of the preferred inflationary models for nearly a decade now. The unique attractor nature of these models in the $n_s-r$ plane have put these models in the sweet-spot of the $n_s-r$ measurement of Planck observations. In this article, we analyse the behaviour of such attractor models in a Warm Inflation setup to investigate whether the attractor nature of these models can be retained even when the dynamics deviates from the standard Cold inflationary dynamics. We have chosen to analyse these models in a strongly dissipative Warm inflation setup, namely the Minimal Warm Inflation, as in such a setup the inflationary dynamics significantly departs from the standard Cold inflation dynamics. We observe that the departure from the standard Cold inflation dynamics destroys the unique attractor nature of such models. The analysis clearly indicates that the attractor nature of these $\alpha$-attractor models is quite unique to the standard Cold inflationary dynamics. However, on a positive note, the analysis indicates that the $\alpha$-attractor models may be made in tune with the recent ACT results in Warm inflation for certain parameter ranges.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2025)·12 citations
22. 22*

    Searching for Long-Lived Particles in Free Neutron Experiments

    B. Meirose🇸🇪 · R. Nieuwenhuis🇸🇪 · R. Pasechnik🇸🇪 · H. Gisbert🇪🇸 · L. Vale Silva🇪🇸 · D. Milstead🇸🇪

    We explore the decay of free neutrons into exotic long-lived particles, whose decays could be detected in the next-generation free neutron experiments. We show that such a possibility is viable as long as the exotic particle is highly mass-degenerate with the neutron, avoiding exclusion by large-volume detectors. We estimate the number of observable events and identify the most promising final states from both theoretical and experimental perspectives. Our analysis highlights the unique capability of the HIBEAM-NNBAR experiment at the European Spallation Source to probe this unexplored region of parameter space, opening a new avenue for exploring physics beyond the Standard Model. We estimate that several events per year could be observed in the NNBAR experiment.

    ↳ hep-exhep-phJ.Phys.G(2025)·2 citations
23. 23*

    Heavy-heavy and heavy-light mesons in cold nuclear matter

    J. J. Cobos-Martínez🇲🇽 · Guilherme N. Zeminiani🇧🇷 · Kazuo Tsushima🇧🇷

    We review the in-medium modifications of effective masses (Lorentz scalar potentials or phenomenon of mass shift) of heavy-heavy and heavy-light mesons in symmetric nuclear matter and their nuclear bound states. We use a combined approach with the quark-meson coupling (QMC) model and an effective Lagrangian. As demonstrated by the cases of pionic and kaonic atoms, studies of meson-nucleus bound state can provide us with important information on chiral symmetry in dense nuclear medium. In this review, we treat the mesons, $K,K^{\ast },D,D^{\ast },B,B^{\ast },\eta ,{\eta }^{\prime },\varphi ,{\eta }_c,J/\psi ,{\eta }_b,{\rm Y}$, and $B_c$, where our emphasys is on the heavy mesons. In addition, we also present some new results for the $B_c$-nucleus bound states.

    ↳ nucl-thhep-exhep-phnucl-exSymmetry(2025)·4 citations
24. 24*

    The geometric bookkeeping guide to Feynman integral reduction and $\epsilon$-factorised differential equations

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

    We report on three improvements in the context of Feynman integral reduction and $\epsilon$-factorised differential equations: Firstly, we show that with a specific choice of prefactors, we trivialise the $\epsilon$-dependence of the integration-by-parts identities. Secondly, we observe that with a specific choice of order relation in the Laporta algorithm, we directly obtain a basis of master integrals, whose differential equation on the maximal cut is in Laurent polynomial form with respect to $\epsilon$ and compatible with a particular filtration. Thirdly, we prove that such a differential equation can always be transformed to an $\epsilon$-factorised form. This provides a systematic algorithm to obtain an $\epsilon$-factorised differential equation for any Feynman integral. Furthermore, the choices for the prefactors and the order relation significantly improve the efficiency of the reduction algorithm.

    ↳ hep-thhep-phPRL(2026)·32 citations
25. 25*

    Chiral interactions of fermions and massive gauge fields in Kaluza-Klein models

    Joao Baptista🇵🇹

    In Kaluza-Klein theory, gauge fields on $M_4$ arise as components of a higher-dimensional metric defined on $M_4\times K$. The traditional expectation is that all the gauge fields of the Standard Model are linked to exact Killing vector fields on the internal space. This paper questions that assumption and investigates the properties of 4D gauge fields linked to non-Killing fields on $K$. It is shown that they have massive yet arbitrarily light bosons; they can mix fermions with different masses; and they can have asymmetric couplings to left- and right-handed fermions. None of these properties is easily satisfied by gauge fields linked to internal isometries. So the massive gauge fields produced in this manner circumvent traditional no-go arguments and offer a geometric source of chiral interactions with fermions. This may help to model the weak force within the Kaluza-Klein framework. Technically, the paper uses the language of spin geometry and Riemannian submersions. It studies the higher-dimensional Dirac operator with non-trivial background metrics. The results are derived for a general $K$. They are illustrated explicitly in the simpler cases where $K$ is the two-sphere and the two-torus.

    ↳ hep-thhep-phmath-phmath.DG+1JHEP(2026)·1 citation
26. 26*

    Core-Corona Decomposition of Very Compact (Neutron) Stars: Accounting for Current Data of XTE J1814-338

    Rico Zöllner🇩🇪 · Burkhard Kämpfer🇩🇪

    A core-corona decomposition of compact (neutron) star models was compared with the current mass-radius data of the outlier XTE~J1814-338. The corona (which may also be dubbed the envelope, halo or outer crust) is assumed to be of Standard Model matter, with an equation of state that is supposed to be faithfully known and accommodates nearly all other neutron star data. The core, solely parameterized by its mass, radius and transition pressure, presents a challenge regarding its composition. We derived a range of core parameters needed to describe the current data of XTE J1814-338.

    ↳ astro-ph.HEastro-ph.SRhep-phAstronomy(2025)·3 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.