Mon·Oct 27, 2025Monday·October 27, 2025

1. 01*

   Natural supersymmetry at a muon collider

   Howard Baer🇺🇸 · Vernon Barger🇺🇸 · Jessica Bolich🇺🇸 · Dibyashree Sengupta🇮🇹 · Kairui Zhang🇺🇸

   There is great interest within the particle physics community for building a ${\mu }^{+}{\mu }^{-}$ collider with center-of-mass (CoM) energies ranging from $\sqrt{s}\sim$ 1-14 TeV. For Beyond-the-Standard-Model (BSM) physics, natural supersymmetry seems perhaps the most motivated, plausible extension of the Standard Model. Here, we examine what can be accomplished by a muon collider with regards to natural SUSY at various muon collider CoM energies. In natural SUSY -- especially in the guise that would emerge from the string landscape -- one expects sparticles to be spread over two orders of magnitude in mass values. A muon collider with highly variable beam energies would be most useful for targeting 2-body reaction thresholds and Higgs boson resonances.

   hep-phPRD(2026)·3 citations
2. 02*

   Nonleptonic ${\Omega }_b^{\ast }\to {\Omega }_c^{\ast }P(V)$ weak transitions in QCD

   A. Amiri🇮🇷 · K. Azizi🇮🇷

   We investigate the nonleptonic two-body weak decays of the single bottom baryon ${\Omega }_b^{\ast }$ into ${\Omega }_c^{\ast }P(V)$ final states within the factorization framework. Employing this framework and incorporating the contributions from the current-current operators, we compute the tree-level decay amplitudes and decay widths of the ${\Omega }_b^{\ast }\to {\Omega }_c^{\ast }P(V)$ processes in terms of the ${\Omega }_b^{\ast }\to {\Omega }_c^{\ast }$ transition form factors. Here, $P$ and $V$ denote pseudoscalar and vector mesons, respectively. Using the form factors obtained in our previous work, we evaluate the numerical values of the decay widths for the dominant nonleptonic weak channels. This study complements our previous analysis of the semileptonic weak transitions ${\Omega }_b^{\ast }\to {\Omega }_c^{\ast }\ell {\bar{\nu }}_{\ell }$ reported in Ref. [1], thereby providing a detailed investigation of dominant ${\Omega }_b^{\ast }\to {\Omega }_c^{\ast }$ weak decays of the ${\Omega }_b^{\ast }$ baryon.

   hep-phhep-exhep-latNPB(2026)·1 citation
3. 03*

   Electromagnetic Leptogenesis -- an EFT-Consistent Analysis via Wilson Coefficients. Part II. Low-Scale, Resonant Regime

   Rin Takada🇯🇵

   We study electromagnetic leptogenesis (EMLG) in the low-scale, resonant regime within a fully effective-field-theory (EFT)--consistent framework. Starting from a UV Lagrangian and performing a one-loop matching to obtain the gauge-invariant dipole operator $O_{NB}$ with its Wilson coefficient $C_{NB}$, we implement the Pilaftsis--Underwood resummation for the self-energy contributions to the CP asymmetries and evolve a flavour covariant transport system across the electroweak window. In the quasi-degenerate limit $M_m-M_i\simeq {\Gamma }_m/2$, the CP-odd source acquires a Breit--Wigner--form enhancement whereas the washout saturates, with the freeze-out baryon asymmetry achieving $Y_B^{\mathrm{FO}}\gtrsim 10^{-10}$ across the strong-washout regime, comfortably above the observed value $Y_B^{\mathrm{obs}}\simeq 8.7\times 10^{-11}$. This establishes resonant EMLG at $O(100)\mathrm{GeV}$ as a viable EFT-based mechanism for the baryon asymmetry of the Universe.

   hep-phJHEP(2026)·0 citations
4. 04*

   WimPyC: an extension module of WimPyDD for the calculation of WIMP capture in celestial bodies

   Sunghyun Kang (CQUeST and Sogang U.)🇰🇷 · Stefano Scopel (CQUeST and Sogang U.)🇰🇷 · Gaurav Tomar (APJ Abdul Kalam Tech. U.)🇮🇳

   We introduce WimPyC, a Python code for the calculation of the capture rate of Weakly Interacting Massive Particles (WIMPs) by celestial bodies through nuclear scattering in the optically thin regime. WimPyC is an extension of the WimPyDD code, that calculates WIMP-nucleus scattering signals in direct detection (DD) experiments, and allows to combine DD and capture in celestial bodies in virtually any scenario within the framework of Galilean-invariant non-relativistic effective theory (NREFT), including inelastic scattering, an arbitrary WIMP spin and a generic WIMP velocity distribution in the Galactic halo. WimPyDD and WimPyC are suitable for both top-down approaches, where the interaction operators of a high-energy physics model are matched to those of the NREFT, and to bottom-up studies, where the Wilson coefficients of the NREFT are explored in a model-independent way and/or where the velocity distribution is written in terms of a superposition of streams taken as free parameters. As in the case of WimPyDD WimPyC exploits the factorization of the three main components that enter in the calculation of the capture rate: i) the Wilson coefficients that encode the dependence of the signals on the ultraviolet completion of the effective theory; ii) a response function that depends on the nuclear physics; iii) the halo function that depends on the WIMP velocity distribution. In WimPyC these three components are calculated and stored separately for later interpolation and combined together only as the last step of the signal evaluation procedure. This makes the phenomenological study of the capture rate with WimPyC transparent and improves computational speed.

   hep-phastro-ph.COComput.Phys.Commun.(2026)·4 citations
5. 05*

   $a_0(980)$ and $f_0(980)$ excitation in the $D^{+}\to {\pi }^{+}\eta \eta$ decay

   Jing Song🇨🇳 · Yi-Yao Li🇨🇳 · Melahat Bayar🇪🇸 · Eulogio Oset🇪🇸

   We have made a thorough study of the $D^{+}\to {\pi }^{+}\eta \eta$ reaction, recently measured by the BESIII collaboration, which shows an abnormal strength at high invariant masses in the $\pi \eta$ mass distribution. We studied in detail the triangle mechanism and the $f_0(1370)$ excitation modes that have been suggested to explain this abnormal feature, and concluded that they are too small to have any important role in the solution to that problem. We have also studied other possible solutions evaluating the contribution of excitations of other $f_0$, $a_0$ and $f_2$ resonances and reached the same conclusion. Unexpectedly, the solution to the problem is found considering the $f_0(980)$ excitation, with the $f_0(980)$ decaying to two $\eta$, which is tied to the $a_0(980)$ production, and well under control. At the same time, the consideration of the $f_0(980)$ excitation solves another non reported problem, which is the $\eta \eta$ mass distribution that comes when only the $a_0(980)$ resonance is allowed to be excited, which produces a large deficiency at low invariant masses compared with experiment.

   hep-phPRD(2026)·2 citations
6. 06*

   Optimized QCD two-loop correction to exclusive double $J/\psi$ production at B factories

   Wen-Long Sang🇨🇳 · Feng Feng🇨🇳 · Yu Jia🇨🇳 · Zhewen Mo🇨🇳 · Jichen Pan🇨🇳 · Jia-Yue Zhang🇺🇸

   We report the calculation of the process $e^{+}{e}^{-}\to J/\psi J/\psi$ up to next-to-next-to-leading order (NNLO) at a center-of-mass (CM) energy of $\sqrt{s}=10.58$ GeV. We employ an improved NRQCD factorization approach, decomposing the amplitude into photon-fragmentation and non-fragmentation components. The fragmentation contribution is determined using the measured $J/\psi$ decay constant, while the interference and non-fragmentation parts are computed at NNLO in ${\alpha }_s$ and lowest order in velocity. In this optimized scheme, both $\mathcal{O}({\alpha }_s)$ and $\mathcal{O}({\alpha }_s^2)$ corrections in the interference part are positive and exhibit good convergence. The non-fragmentation part is numerically insignificant. Our results indicate that with the projected 50 ${\mathrm{ab}}^{-1}$ dataset at \texttt{Belle 2}, the prospects for observing exclusive double $J/\psi$ production are very promising.

   hep-phPoS(2025)·0 citations
7. 07*

   Semileptonic ${\Lambda }_c\to \Lambda \ell {\nu }_{\ell }$ Decays in Light-Cone QCD Sum Rules with ${\Lambda }_c$ Distribution Amplitudes

   T.M.Aliev🇹🇷 · S.Bilmis🇹🇷 · M.Savci🇹🇷

   We study the semileptonic decay of its SU(3) partner, the ${\Lambda }_c\to \Lambda {\ell }^{+}{\nu }_{\ell }$ ($\ell =e,\mu$) transition, within the framework of light-cone QCD sum rules (LCSR) by using the distribution amplitudes of heavy ${\Lambda }_c$ baryon. The numerical analysis is performed using two different sets of ${\Lambda }_c$ baryon light-cone distribution amplitudes. The resulting form factors are parametrized by a model-independent $z$-series expansion and used to compute the differential and total decay widths. Our predictions for the branching fractions are in good agreement with the latest BESIII measurements and with lattice-QCD results.

   hep-phEPJC(2026)·2 citations
8. 08*

   The Standard Model partial unification scale as a guide to new physics model building

   Isabella Masina🇮🇹 · Mariano Quiros🇪🇸

   In the Standard Model, partial unification of the non-Abelian running gauge couplings is achieved at the scale ${\mu }_{32}^{SM}\approx 2.8\times 10^{16}$ GeV. Elaborating on this fact, we discuss a simple general parametrization for the new physics corrections leading to full unification at some scale $M_X$. We show that for any new physics model such that the corrections to the non-Abelian couplings are equal (or nearly so), $M_X$ is equal (or close to) the partial unification scale ${\mu }_{32}^{SM}$; the latter scales could be disentangled only if the corrections to the non-Abelian couplings are significantly different. We explore how the parametrization works for some relevant models with new physics below $M_X$, as low energy supersymmetry, split supersymmetry, etc. As for models with a desert up to $M_X$, we explore in particular how the parametrization works for string inspired corrections; we find a phenomenologically remarkable possibility for unification at about 100 TeV, suggesting a low string scale, in addition to the more conservative possibility for unification at ${\mu }_{32}^{SM}$; for models with power-low running/threshold corrections, we also outline an interesting connection with the number of fermion families propagating in the bulk.

   hep-phhep-thPRD(2026)·1 citation
9. 09*

   Determination of the strong coupling from high-energy data

   S. Alekhin🇩🇪 · M.V. Garzelli🇩🇪 · S. Moch🇩🇪 · O. Zenaiev🇩🇪

   We determine the strong coupling from high-energy data for the Drell-Yan (DY) process and top-quark hadro-production collected at the Large Hadron Collider and the Tevatron combined with the world data on deep-inelastic scattering (DIS) and fixed-target DY data. The theory description uses results at next-to-next-to-leading order in perturbative QCD in the $\overline{\mathrm{MS}}$-scheme together with leading order QED evolution. The DIS data are subject to stringent kinematic cuts to suppress the contribution of power corrections. We apply a cut on the hadronic invariant mass squared $W^2\ge 12.5$GeV${}^2$ together with a series of cuts on momentum transfer squared $Q^2$. Discarding higher-twist terms we find that the value of strong coupling ${\alpha }_s(m_Z)$ preferred by the data stabilizes at large enough cuts on $Q^2$, when low-$Q^2$ DIS data sensitive to power corrections are effectively removed. In particular, we extract the value of ${\alpha }_s(m_Z,N_f=5)=0.1152\pm 0.008$ for $N_f=5$ light flavors with the cut $Q^2>10$GeV${}^2$. In the absence of higher-twist terms less tight cuts on $Q^2$ show a clear deterioration of the fit and lead to rising values of the strong coupling, shifted upwards by about two standard deviations.

   hep-phhep-exEPJC(2026)·4 citations
10. 10*

    Gravitational waves from the sound shell model: direct and inverse phase transitions in the early Universe

    Giulio Barni🇪🇸 · Simone Blasi🇩🇪 · Eric Madge🇪🇸 · Miguel Vanvlasselaer🇧🇪

    Cosmological phase transitions are a frequent phenomenon in particle physics models beyond the Standard Model, and the corresponding gravitational wave signal offers a key probe of new physics in the early Universe. Depending on the underlying microphysics, the transition can exhibit either direct or inverse hydrodynamics, leading to a different phenomenology. Most studies to date have focused on direct transitions, where the cosmic fluid is pushed or dragged by the expanding vacuum bubbles. In contrast, inverse phase transitions are characterized by fluid profiles where the plasma is sucked in by the expanding bubbles. Using the sound shell model, we derive and compare the gravitational wave spectra from sound waves for direct and inverse phase transitions, providing new insights into the potential observable features and the possibility of discriminating among the various fluid solutions in gravitational wave experiments.

    hep-phastro-ph.COgr-qcJCAP(2026)·11 citations
11. 11*

    Five-loop beta function for gauge theories: computations, results and consequences

    F. Herzog (U. Edinburgh, Higgs Ctr. Theor. Phys.) B. Ruijl (Ruijl Research, Zug) · T. Ueda (Juntendo U.) · J. Vermaseren (Nikhef, Amsterdam) · A. Vogt (Liverpool U., Dept. Math.)

    At the end of 2016, we computed the five-loop (N${}^4$LO) contributions to the beta function in perturbative Quantum Chromodynamics (QCD), its generalization to non-Abelian gauge theories with a simple compact Lie group, and for Quantum Electrodynamics (QED). Here we recall main tools used in and specifically developed for this computation and its main analytic and numerical results. The development work carried out for this project facilitated further even more involved analytic five-loop computations. We briefly summarize also their numerical QCD results for Higgs-boson decay to hadrons in the heavy-top limit and for two N${}^4$LO splitting functions for the evolution of quark distributions of hadrons. The latter lead to a first realistic estimate of the five-loop contribution to another important quantity in perturbative QCD, the quark cusp anomalous dimension.

    hep-ph1 citation
12. 12*

    Electroweak corrections to $gg\to \gamma \gamma$

    Gabriele Fiore🇨🇭 · Ciaran Williams🇺🇸

    We present the electroweak corrections for the production of a photon pair through gluon fusion, focusing on the contribution from the first two generations of quarks. The two-loop amplitude is calculated using a series of projection operators which define scalar form factors. In order to evaluate the Master Integrals which appear in this process we employ both generalized polylogarithms and Chen-iterated integrals. In order to perform a phenomenological study we develop a semi-numerical evaluation of the Master Integrals employing a fitting procedure to speed up the evaluation of burdensome higher weight contributions. We present results for the LHC, finding corrections of around a couple of percent to the leading order $gg\to \gamma \gamma$ process. Our results are implemented into the parton-level Monte Carlo code \texttt{MCFM}.

    hep-phJHEP(2026)·0 citations
13. 13*

    Coherent elastic scattering of low energy photons by neutrons

    P.O. Kazinski🇷🇺 · A.A. Sokolov🇷🇺

    The Compton process with the initial states of photons and neutrons described by the density matrices of a general form is studied for low energies of photons. The coherent contribution to the inclusive probability to record a photon is investigated in detail. This contribution gives the hologram of the neutron one-particle density matrix. The evolution of the Stokes parameters of scattered photons is described. The susceptibility tensor of a neutron gas and a wave packet of a single neutron is obtained. The explicit expression for the photon polarization operator in the presence of free neutrons is derived. It turns out that this polarization operator possesses pole singularities in the short wavelength approximation. These singularities corresponding to the additional degrees of freedom are identified with plasmons and the respective plasmon-polaritons are described. There are eight independent plasmon-polariton modes in a neutron gas and on a single neutron wave packet. Some plasmon-polariton modes prove to be tachyonic and unstable manifesting a spontaneous generation of the magnetic field. The estimates of the parameters of the neutron gas when it becomes ferromagnetic are found. In the infrared limit, the neutron wave packet behaves in coherent Compton scattering as a point particle with dynamical magnetic moment, the additional degrees of freedom being reduced to the dynamical part of the magnetic moment.

    hep-phnucl-th2 citations
14. 14*

    Subleading Effects in Soft-Gluon Emission at One-Loop in Massive QCD

    Michał Czakon🇩🇪 · Kilian Erhard Minguez🇩🇪 · Felix Eschment🇩🇪

    We provide the last missing ingredient necessary to approximate one-loop amplitudes in QCD with massive quarks in the limit of vanishing energy of a single gluon up to terms suppressed by this energy. Our main result is a soft operator acting in color and spin space that manipulates the momenta of the hard partons while keeping them on-shell and respecting momentum conservation. Additionally, we provide a complete expression for the subleading term of the expansion of an arbitrary tree-level amplitude in the limit where the momenta of a massless quark and a massless anti-quark of the same flavor become collinear. This limit is necessary to obtain the one-loop soft approximation whenever the process involves such a quark-anti-quark pair. Interestingly, the result involves a high-energy limit.

    hep-phJHEP(2026)·1 citation
15. 15*

    Electroweak Baryogenesis with BARYONET: a self-contained review of the WKB approach

    Giulio Barni🇪🇸

    We present a comprehensive, self-contained pedagogical computation of the baryon asymmetry of the Universe within electroweak baryogenesis (EWBG), from the derivation of the semiclassical, CP-dependent force to the formulation and solution of the transport equations obtained from the Boltzmann equations$-$all implemented in the open-source code BARYONET. Our analysis follows the semiclassical WKB approach, where spatially varying complex masses across expanding bubble walls feel CP-violating forces that bias plasma transport. Starting from the stationary Boltzmann equation in the wall frame and projecting onto a hierarchy of velocity moments, we derive a compact, fluid-like system of coupled differential equations for chemical potentials and velocity perturbations. After obtaining the solutions, one can define the left-handed baryon chemical potential, which acts as the source term for the weak sphalerons. These processes generate the baryon asymmetry in front of the wall, which is subsequently frozen once it passes through it. We validate the framework against established formalisms and provide benchmarks in representative scenarios, including singlet extensions of the Standard Model, two-Higgs-doublet models, and Higgs$-{\varphi }^6$ constructions. The resulting BARYONET implementation delivers an automated, reproducible pipeline for WKB-based baryogenesis studies, connecting formal derivations with phenomenological applications. In parallel, we revisit standard EWBG ingredients$-$diffusion constants, Yukawa/helicity-flip rates, and strong/weak sphaleron rates$-$to clarify conventions, update numerical inputs, and present a pedagogical derivation, ensuring transparent reproducibility.

    hep-phastro-ph.COhep-thSciPost Phys.(2026)·13 citations
16. 16*

    Superhorizon Isocurvature as a Window into Dark Matter Production

    Christopher Gerlach🇩🇪 · Wolfram Ratzinger🇮🇱 · Pedro Schwaller🇩🇪

    In the presence of primordial isocurvature perturbations, for example in a separate dark radiation sector, the superhorizon evolution of curvature perturbations becomes nontrivial. If the dark sector is radiation-like and constitutes a significant fraction of the energy density, its isocurvature can imply isocurvature in the inflaton sector even without direct interactions between the sectors. In this article, we revisit superhorizon curvature and isocurvature evolution in the long-wavelength limit systematically, drawing a simple picture of how to understand the nature of these fluctuations from first principles and without brute-force cosmic perturbation theory. We show how the described setup is able to source isocurvature in simple models of dark matter such as freeze-in and freeze-out and demonstrate that future measurements of matter and neutrino isocurvature can potentially discriminate between these two mechanisms.

    hep-phastro-ph.CO3 citations
17. 17*

    Seafloor Topography Enhances KM3NeT Sensitivity to ANITA-like Events

    Carlos A. Argüelles🇺🇸 · Toni Bertólez-Martínez🇪🇸 · Alba Burgos-Mondéjar🇺🇸 · Anne-Katherine Burns🇪🇸 · Jacobo Lopez-Pavon🇪🇸 · Jordi Salvado🇪🇸

    In this article, we introduce the concept of \textit{topographic enhancement} in the context of ultra-high-energy neutrino detection by underwater neutrino telescopes. We demonstrate that the local topography around KM3NeT/ARCA can increase the detection efficiency in scenarios involving long-lived particles by up to a factor of $\sim 3$ due to the presence of an underwater mountain range in the direction of Malta. We consider a simplified model-independent approach that parametrizes the new physics able to generate both track-like and cascade-like signals in neutrino telescopes. When explaining the KM3-230213A event with a diffuse dark flux hypothesis, including its azimuthal direction--in addition to the zenith angle--provides additional constraints on the parameter space. In this effective model, the observations by KM3NeT and ANITA-IV can be simultaneously explained and the global tension with the lack of a corresponding detection in IceCube is reduced to 2.4 sigma. This work underscores the importance of incorporating topographic effects in the design and optimization of next-generation neutrino telescopes, as is done in the context of mountain-based detectors such as TAMBO. We present a numerical code which can be used to easily extend this topographical analysis to other experiments.

    hep-phastro-ph.HEhep-ex2 citations
18. 18*

    Auger@TA: In-situ Cross-Calibration of the World's Largest Cosmic Ray Observatories

    Adriel G B Mocellin🇺🇸 · J. Caraça-Valente🇺🇸 · C. Covault🇺🇸 · E. Dalcan · T. Fujii · S. Im · R. James🇬🇧 · J. Johnsen🇺🇸 · K.H. Kampert🇩🇪 · H. Kern · J.N. Matthews · E. Mayotte🇺🇸 and 12 other authors

    The Pierre Auger Observatory (Auger) and the Telescope Array (TA) are the world's two largest ultra-high-energy cosmic ray (UHECR) observatories. They operate in the Southern and Northern hemispheres, respectively, at similar latitudes but with distinct surface detector (SD) designs. A significant challenge in studying UHECR physics across the full sky is the apparent discrepancy in flux measurements between the two experiments. This discrepancy could arise from astrophysical differences and/or systematic effects related to their detector designs and sensitivities to extensive air shower components. To address this, the Auger@TA working group aims to cross-calibrate the two observatories with a self-triggering micro-Auger array within the TA array. This micro-array consists of eight Auger Surface Detector (SD) stations equipped with Water Cherenkov Detectors (WCDs) and AugerPrime Surface Scintillator Detectors. Seven SD stations, configured with a centered-1-PMT design, are arranged in a hexagonal pattern with one station in the center, with 1.5 km spacing, mirroring the Auger layout. The eighth station, which features a standard 3-PMT Auger station, is located in conjunction with a TA detector at the center of the hexagon, forming a triplet for high-statistics and low-uncertainty cross-calibration. A custom communication system that uses readily available components enables seamless communication between stations and remote access to each station through a central computer. The micro-array is now fully deployed, and initial data-taking is about to start. This presentation will detail the instrumentation, communication systems, central data acquisition system, expected performance of the micro-array, and preliminary results as appropriate.

    ↳ astro-ph.HEastro-ph.IMhep-ph1 citation
19. 19*

    Gaussian Processes for Inferring Parton Distributions

    Yamil Cahuana Medrano🇺🇸 · Hervé Dutrieux🇺🇸 · Joseph Karpie🇺🇸 · Kostas Orginos🇺🇸 · Savvas Zafeiropoulos🇫🇷

    The extraction of parton distribution functions (PDFs) from experimental or lattice QCD data is an ill-posed inverse problem, where regularization strongly impacts both systematic uncertainties and the reliability of the results. We study a framework based on Gaussian Process Regression (GPR) to reconstruct PDFs from lattice QCD matrix elements. Within a Bayesian framework, Gaussian processes serve as flexible priors that encode uncertainties, correlations, and constraints without imposing rigid functional forms. We investigate a wide range of kernel choices, mean functions, and hyperparameter treatments. We quantify information gained from the data using the Kullback Leibler divergence. Synthetic data tests demonstrate the consistency and robustness of the method. Our study establishes GPR as a systematic and non-parametric approach to PDF reconstruction, offering controlled uncertainty estimates and reduced model bias in lattice QCD analyses.

    ↳ hep-lathep-phJHEP(2026)·14 citations
20. 20*

    Short-Range Correlations and Meson-Exchage Currents in Electron and Neutrino Scattering

    Paloma R. Casale🇪🇸 · Jose E. Amaro🇪🇸

    We investigate meson-exchange currents (MEC) in the one-particle emission transverse response of nuclear matter, incorporating short-range correlations via the Bethe-Goldstone equation with a realistic nucleon-nucleon interaction. The interference between one-body and two-body currents, strengthened by the high-momentum components of correlated pairs, produces a marked enhancement of the transverse response. We also indicate how the formalism extends to neutrino scattering, where similar effects are expected to impact oscillation experiments.

    ↳ nucl-thhep-phNucl.Theor.(2025)·0 citations
21. 21*

    Constraints on ultraheavy dark matter from the CDEX-10 experiment at the China Jinping Underground Laboratory

    Y. F. Wang🇨🇳 · L. T. Yang🇨🇳 · Q. Yue🇨🇳 · K. J. Kang🇨🇳 · Y. J. Li🇨🇳 · H. P. An🇨🇳 · Greeshma C.🇹🇼 · J. P. Chang🇨🇳 · H. Chen🇨🇳 · Y. H. Chen🇨🇳 · J. P. Cheng🇨🇳 · J. Y. Cui🇨🇳 and 76 other authors

    We report a search for ultraheavy dark matter (UHDM) with the CDEX-10 experiment at the China Jinping Underground Laboratory. Using a Monte Carlo framework that incorporates Earth shielding effects, we simulated UHDM propagation and energy deposition in p-type point-contact germanium detectors. Analysis of 205.4 kg$\cdot$day exposure in the 0.16--4.16 keVee range showed no excess above background. Our results exclude the spin-independent UHDM-nucleon scattering with two cross section scales, with the UHDM mass from $10^6$ to $10^{11}$ GeV, and provide the most stringent constraints with solid-state detectors below $10^8$ GeV.

    ↳ hep-exhep-phphysics.ins-detPRD(2026)·1 citation
22. 22*

    Subatomic Heroes

    Anshika Bansal🇩🇪 · Guido Bell🇩🇪 · Aritra Biswas🇩🇪 · Diptaparna Biswas🇩🇪 · Anastasia Boushmelev🇩🇪 · Carsten Busse🇩🇪 · Markus Cristinziani🇩🇪 · Carmen Diez Pardos🇩🇪 · Qader Dorosti🇩🇪 · Sebastian Edelmann🇩🇪 · Thorsten Feldmann🇩🇪 · Ivor Fleck🇩🇪 and 35 other authors

    Sharing the amazing achievements of the (particle) physics world with the general public is at the heart of the mission of the Subatomic Heroes, based at the University of Siegen, Germany. Originally this started out as an endeavor of theoretical particle physics, now we are steadily spreading out to cover and include more branches of physics and science. Our activities range from merging art with public physics lectures via marvelous artistic performances at the local theater, over dedicated events for high-school students, to our Subatomic Heroes channel on Instagram and TikTok where you may also find out when and where our famous "hadronic ice-cream" will be served next! So follow us on https://www.instagram.com/subatomic_heroes and https://www.tiktok.com/@subatomic_heroes.

    ↳ physics.ed-phhep-exhep-lathep-phPoS(2026)·0 citations
23. 23*

    Synergy between CSST and third-generation gravitational-wave detectors: Inferring cosmological parameters using cross-correlation of dark sirens and galaxies

    Ya-Nan Du🇺🇸 · Ji-Yu Song🇺🇸 · Yichao Li🇺🇸 · Shang-Jie Jin🇺🇸 · Ling-Feng Wang🇨🇳 · Jing-Fei Zhang🇺🇸 · Xin Zhang🇺🇸

    Gravitational-wave (GW) events are generally believed to originate in galaxies and can thus serve, like galaxies, as tracers of the universe's large-scale structure. In GW observations, waveform analysis provides direct measurements of luminosity distances; however, without relying on a specific cosmological model, the redshifts of GW sources cannot be determined due to the mass-redshift degeneracy. By cross-correlating GW events with galaxies, one can establish a correspondence between luminosity distance and redshift shells, enabling cosmological inference. In this work, we explore the scientific potential of cross-correlating GW sources detected by third-generation (3G) ground-based GW detectors with the photometric redshift survey of the China Space Station Survey Telescope (CSST). We find that the constraint precisions of the Hubble constant and the matter density parameter can reach $1.04\%$ and $2.04\%$, respectively. Additionally, we have also constrained the precision of the GW clustering bias parameter. These results highlight the significant potential of the synergy between CSST and 3G ground-based GW detectors in constraining cosmological models and probing GW source formation channels using cross-correlation of dark sirens and galaxies.

    ↳ astro-ph.COgr-qchep-phPRD(2026)·12 citations
24. 24*

    Exploring the Co-SIMP dark matter model using the 21-cm signal from the dark ages

    Debarun Paul🇮🇳 · Sourav Pal🇮🇳 · Deepthi Moorkanat🇮🇳 · Antara Dey🇮🇳 · Amit Dutta Banik🇮🇳 · Rajesh Mondal🇮🇳

    The redshifted 21-cm signal from the dark ages offers a powerful probe of cosmological models and the underlying dark matter (DM) microphysics. We investigate deviations from the standard $\Lambda$CDM prediction, an absorption trough of approximately $-40.6\mathrm{mK}$ at redshift $z\simeq 85.6$, in the context of co-SIMP (strongly interacting massive particle) DM. The co-SIMP interaction strength is encoded by the parameter $C_{\mathrm{int}}$, incorporating the masses of DM and standard model (SM) particles, the interaction cross-section, and the amount of heat exchange between the two sectors. Increasing $C_{\mathrm{int}}$ deepens the absorption feature and shifts the trough to higher redshifts in the global signal. For $C_{\mathrm{int}}=1.0$, the minimum brightness temperature reaches $-50.6,\mathrm{mK}$ at $z\simeq 86.2$. The 21-cm power spectrum increases with $C_{\mathrm{int}}$ in addition to the global signal. We assess the detectability of these signatures using signal-to-noise ratio (SNR) and Fisher forecasts. The maximum SNR reaches $\sim 15.7$ for $C_{\mathrm{int}}=1.0$ for the global signal. Fisher forecasts for $1,000$ hours of integration time show that this model can be distinguished from a null-signal at $4.3\sigma$ and a mild 1.6$\sigma$ from $\Lambda$CDM, improving by an order of magnitude for 100,000 hours. For the 21-cm power spectrum, a $5,{\mathrm{km}}^2$ array with 1,000 hours yields a $4.63\sigma$ detection and mildly separated from the standard scenario at $1.78\sigma$. These findings highlight the potential of the 21-cm cosmology to probe the properties of DM and demonstrate that upcoming dark ages experiments, particularly space-based and lunar observations, can offer a promising avenue to test co-SIMP models.

    ↳ astro-ph.COhep-phMNRAS(2026)·1 citation
25. 25*

    Imprint of the black hole singularity on thermal two-point functions

    Nima Afkhami-Jeddi🇨🇦 · Simon Caron-Huot🇨🇦 · Joydeep Chakravarty🇨🇦 · Alexander Maloney🇨🇦

    We consider two-point functions of light fields at finite temperature and large real frequencies in holographic theories. The thermal system is dual to a single-sided AdS black hole. We show that the high-frequency expansion obtained from the Operator Product Expansion receives exponentially small nonperturbative corrections, which are controlled by null geodesics bouncing off the black hole singularity in the two-sided eternal black hole geometry. We develop a bulk WKB description of these bouncing geodesics and explain how to calculate reflection coefficients at the singularity.

    ↳ hep-thgr-qchep-phPRD(2026)·29 citations
26. 26*

    Can Bose-Einstein condensates enhance radioactive decay?

    Hanzhen Lin🇺🇸 · Yukun Lu🇺🇸 · Wolfgang Ketterle🇺🇸

    This paper lays out the principles of how Bose-Einstein condensates can modify radioactive decay. We highlight the challenges of many modes and short coherence times due to the $\approx$ MeV energies of the emitted radiation. Recent proposals for gamma ray and neutrino lasers claim that using a Bose-Einstein condensate as a source would solve these issues. We show that this is not the case, and the proposed experiments would have a gain of only $10^{-16}$ or smaller. We also analyze proposals for gamma ray lasers based on stimulated annihilation of positronium Bose-Einstein condensates.

    ↳ quant-phhep-phnucl-exphysics.atom-phPRL(2026)·3 citations
27. 27*

    Fundamental impossibility of a superradiant neutrino laser

    Yu-Kun Lu🇺🇸 · Hanzhen Lin🇺🇸 · Wolfgang Ketterle🇺🇸

    Here we address the fundamental question of whether an idealized system of $N$ atoms will show collective behavior and superradiance when it emits fermions instead of photons. We show that for single-fermion emission processes, the maximum emission is $\propto N$ and not $\propto N^2$, which proves the absence of superradiance and shows that the recent proposal to realize a superradiant neutrino laser is impossible. This can be understood as either destructive interference of fermionic transition amplitudes, or Pauli blockade by collective excitations with fermionic nature. We derive the exact solution of the fermionic Dicke problem and analyze the decay dynamics in various regimes. We extend the proof to arbitrary Hamiltonians and show that the jump rate operator for neutrino emission has a maximum eigenvalue of $N$ times the single-particle rate ${\Gamma }_0$. States with low excitation can show collective behavior and emit at a rate of $N{\Gamma }_0$.

    ↳ quant-phhep-phnucl-exphysics.atom-phPRL(2026)·3 citations
28. 28*

    How to Build an Empirical Speed Distribution for Dark Matter in the Solar Neighborhood

    Tal Shpigel🇺🇸 · Dylan Folsom🇺🇸 · Mariangela Lisanti🇺🇸 · Lina Necib🇺🇸 · Mark Vogelsberger🇺🇸 · Lars Hernquist🇺🇸

    The dark matter flux in a direct detection experiment depends on its local speed distribution. This distribution has been inferred from simulations of Milky Way-like galaxies, but such models serve only as proxies, given that no simulation directly captures the detailed evolution of our own Galaxy. This motivates alternative approaches that obtain this distribution directly from observations. In this work, we utilize 98 Milky Way analogues from the TNG50 simulation to develop and validate a procedure for inferring the dark matter speed distribution using the kinematics of nearby stars. We find that the dark matter that originated from old mergers, plus that from recent nonluminous accretions, is well described by a Maxwell-Boltzmann speed distribution centered at the local standard-of-rest velocity. Meanwhile, recently accreted dark matter from massive mergers has speeds that can be traced from the associated stellar debris of these events. The stellar populations systematically underestimate the velocity dispersion of their dark matter counterparts, but a simple kinematic boost brings the two into good alignment. Using the TNG50 host galaxies, we demonstrate that combining these two contributions provides an accurate reconstruction of the local dark matter speeds. As an application of the procedure to our own Galaxy, we utilize stellar kinematic data from Gaia to quantify how the dark matter remnants from the Milky Way's last major merger impact its speed distribution in the solar neighborhood.

    ↳ astro-ph.GAastro-ph.COhep-phApJ(2026)·4 citations
29. 29*

    Suppressed "lump" EM signature in radiation pressure dominated accreting massive black hole binaries

    Fabiola Cocchiararo · Alessia Franchini🇮🇹 · Alessandro Lupi · Alberto Sesana🇮🇹

    We investigate the impact of radiation pressure on electromagnetic signatures of accreting massive black hole binaries (MBHBs) at milli-parsec separations, using 3D hyper-Lagrangian resolution hydrodynamical simulations. We model binaries embedded in a self-gravitating circumbinary disc that evolves following an adiabatic equation of state, including viscous heating and black-body cooling. Focusing on binaries with a total mass of $10^6{M}_{\odot }$, eccentricities $e=0,0.45,0.9$ and mass ratios $q=1,0.7$, we find that radiation pressure significantly affects both the spectral energy distributions (SEDs) and the light curves (LCs). The emission from the mini-discs shifts from the optical towards UV frequencies and with a peak luminosity orders of magnitude higher, while the circumbinary disc becomes colder and dimmer as a result of its geometrically thinner configuration. Temporal variability is affected as well: near UV and soft-X ray fluxes are higher and more variable. Crucially, radiation pressure suppresses the characteristic "lump" formation in equal-mass circular systems, while a lump is formed for higher eccentricities without imprinting any modulation on the flux. In the circular case we still find a modulation on the cavity edge timescale at a frequency $0.36f_{\mathrm{K}}$, while in eccentric binaries, only robust orbital period modulations ($f=1,2f_{\mathrm{K}}$) are observed, with no modulation associated with the cavity orbital motion. Moreover, the enhanced emission from the mini-discs and streams due to radiation pressure, one redshifted, results in brighter flux in the optical G band, proving detectability of MBHBs signatures even at higher redshift ($z=0.6-1.0$). Our results reveal that radiation pressure plays a crucial role in shaping MBHBs spectral and time-domain features, with implications for their identification in time-domain surveys.

    ↳ astro-ph.HEastro-ph.COhep-ph2 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.