Thu·Sep 25, 2025Thursday·September 25, 2025

1. 01*

   Study of Form Factors and Observables in $B_c^{-}\to {\bar{D}}^{(\ast )0}{\ell }^{-}{\bar{\nu }}_{\ell }$ and $B_c^{-}\to D^{(\ast )-}{\ell }^{+}{\ell }^{-}$ decays

   Utsab Dey🇮🇳 · Soumitra Nandi🇮🇳

   We investigate the decays $B_c^{-}\to {\bar{D}}^{(\ast )0}{\ell }^{-}{\bar{\nu }}_{\ell }$ and $B_c^{-}\to D^{(\ast )-}{\ell }^{+}{\ell }^{-}$ within the Standard Model (SM), employing perturbative QCD (pQCD) form factors that are sensitive to the wave functions of $B_c$ and $D^{(\ast )}$ mesons. Using lattice QCD inputs for $B\to D^{(\ast )}$ and $B_c\to D$ transitions, we extract the shape parameters of the meson wave functions and estimate the $q^2$-dependence of $B_c\to D^{\ast }$ form factors via heavy quark spin symmetry. We present predictions for branching fractions, lepton flavor violating observables, and perform a detailed angular analysis of the cascade decay $B_c^{-}\to D^{\ast -}(\to D^0{\pi }^{-}){\ell }^{+}{\ell }^{-}$, providing SM expectations for several angular observables.

   hep-phJHEP(2026)·3 citations
2. 02*

   Connecting cosmologically decaying dark matter to neutrino physics

   Lea Fuß🇩🇪 · Mathias Garny🇩🇪 · Alejandro Ibarra🇩🇪

   Dark matter decays into invisible particles can leave an imprint in large-scale structure surveys due to a characteristic redshift-dependent suppression of the power spectrum. We present a model with two quasi-degenerate singlet fermions, ${\chi }_1$ and ${\chi }_2$, in which the heavier state decays as ${\chi }_2\to {\bar{\chi }}_1\nu \nu$ on cosmological time-scales, and that also accommodates non-zero neutrino masses. Remarkably, for parameters that yield the correct dark matter abundance via freeze-in and reproduce the observed neutrino masses, dark matter decay can produce detectable signals in forthcoming large-scale structure surveys, a diffuse anti-neutrino flux accessible to JUNO, and a gamma-ray line within the energy range probed by COSI. Both the cosmological lifetime of ${\chi }_2$ as well as the small (radiatively induced) mass splitting among ${\chi }_{1,2}$ are a natural consequence of the mechanism of neutrino mass generation within this model. This highlights the potential role of large-scale structure surveys in probing some classes of neutrino mass models.

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

   Lepton-flavor violation and two loop electroweak corrections to $(g-2{)}_{\mu }$ in the triplets

   Zhao-Yang Zhang🇨🇳

   In the Standard Model (SM), charged lepton flavor-violating (LFV) processes are strictly forbidden, and thus observation of LFV would signal the presence of new physics. Recently, the Muon $g-2$ collaboration at Fermilab reported their final result for the muon magnetic dipole moment (MDM), which is now consistent with the latest SM prediction at the $1\sigma$ level. This imposes a significant constraint on new-physics contributions to $(g-2{)}_{\mu }$. In this work, we study the LFV processes ${\ell }_j^{-}\to {\ell }_i^{-}\gamma$ and ${\ell }_j^{-}\to {\ell }_i^{-}{\ell }_i^{-}{\ell }_i^{+}$ within the framework of the triplet next-to-minimal supersymmetric standard model (TNMSSM). We include two-loop contributions to the muon MDM and investigate the resulting constraints on the model parameter space. Our numerical analysis shows that, in the TNMSSM, doubly charged Higgs bosons and the couplings $Y_L$ and $Y_D$ associated with the Type-I+II seesaw mechanism play a crucial role in both LFV processes and the muon MDM. Moreover, two-loop electroweak corrections have a significant impact on the muon MDM in this framework.

   hep-phPRD(2025)·0 citations
4. 04*

   Charged pion decay in a laser field

   D. Gomez Dumm🇦🇷 · S. Noguera🇪🇸 · N.N. Scoccola🇦🇷

   We study the decays ${\pi }^{+}\to l^{+}{\nu }_l$ in the presence of a background electromagnetic plane wave with circular polarization. We find that, in the presence of this background, the number of hadronic form factors required to describe the pion-to-vacuum amplitude increases from one to four. Three of these form factors are associated with the axial vector current and one with the vector piece, which is in general different from zero. We obtain analytical expressions for the corresponding contributions to the decay width, considering in particular some range of values of interest for the frequency and amplitude of the external wave. For laser frequencies $\omega$ of the order of the eV, it is seen that the main correction to the result obtained in absence of the external field is proportional to the vector form factor, carrying a suppression factor of order $\sim (\omega /m_{\pi }{)}^{4/3}$. In addition, we show that our expressions can be connected with the Kroll-Watson formula, which provides the differential cross section for the scattering of a charged particle by some potential in the presence of a strong external electromagnetic wave. Our analytical results are also compatible with previous numerical calculations obtained in the limit of low amplitude laser fields, offering new insight on some characteristics of these results.

   hep-phPRD(2025)·0 citations
5. 05*

   Plasmon damping in a charged Bose-Einstein condensate model

   José F. Nieves🇺🇸 · Sarira Sahu🇲🇽

   In this work we consider the calculation of the imaginary part of the dispersion relations of the propagating modes in a model of a charged scalar Bose-Einstein (BE) condensate, as well as the contribution to the imaginary part of the longitudinal component of the photon polarization tensor and the dielectric constant. In that model, two modes correspond to the transverse photon polarizations, while the other two modes are combinations of the longitudinal photon and the massive scalar field, which we denote as the $(\pm )$ modes. The dispersion relations of the transverse modes have the usual form for transverse photons in a plasma, and we do not consider here any further. In a previous work we determined the real part of the dispersion relations of the $(\pm )$ modes, as well as the real part of the longitudinal component of of polarization tensor and dielectric constant, which have some unique features. In the appropriate limit, those results reproduce the results obtained for the dielectric constant and dispersion relation in non-relativistic models of the BE condensation of charged scalars. Here we determine, in the same model, their imaginary part. The results can be useful in physical contexts involving the electrodynamics of a charged scalar BE condensate, and can serve as benchmark results for further exploration.

   hep-phPRD(2025)·1 citation
6. 06*

   Probing Invisible Decay of $Z^{\prime }$ at Muon Collider with Topological Data Analysis and Machine Learning

   Jyotiranjan Beuria🇮🇳

   We explore the use of topological data analysis (TDA) combined with machine learning for discriminating standard model backgrounds from the invisible decay of the $Z^{\prime }$ boson associated with monophoton emission at a 3 TeV muon collider. Reconstructed events are mapped into a six-dimensional kinematic space and aggregated into bags of events, from which persistent homology is used to extract Betti number distributions. Within the Multiple Instance Learning paradigm, classifiers trained on these topological descriptors demonstrate significantly improved classification accuracy compared to the conventional ML approaches based on event-wise kinematic inputs. We also draw exclusion contours at 95\% CL in the $(m_{Z^{\prime }},m_{\chi })$ parameter space, highlighting the potential of topological features to extend the discovery reach of future collider experiments.

   hep-ph3 citations
7. 07*

   Phenomenological constraints on QCD transport with quantified theory uncertainties

   Sunil Jaiswal🇺🇸

   We present data-driven, state-of-the-art constraints on the temperature-dependent specific shear and bulk viscosities of the quark-gluon plasma from Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76\mathrm{TeV}$. We perform global Bayesian calibration using the JETSCAPE multistage framework with two particlization ansätze, Grad 14-moment and first-order Chapman-Enskog, and quantify theoretical uncertainties via a centrality-dependent model discrepancy term. When theoretical uncertainties are neglected, the specific bulk viscosity and some model parameters inferred using the two ansätze exhibit clear tension. Once theoretical uncertainties are quantified, the Grad and Chapman-Enskog posteriors for all model parameters become almost statistically indistinguishable and yield reliable, uncertainty-aware constraints. Furthermore, the learned discrepancy identifies where each model falls short for specific observables and centrality classes, providing insight into model limitations.

   hep-phnucl-thPLB(2026)·4 citations
8. 08*

   Study of hidden-charm, doubly-strange pentaquarks in ${\Lambda }_b\to J/\psi {\Xi }^{-}{K}^{+}$ and ${\Xi }_b\to J/\psi {\Xi }^{-}{\pi }^{+}$

   L. Roca🇪🇸 · J. Song🇨🇳 · E. Oset🇪🇸

   Hidden-charm pentaquark states with double strangeness, $P_{css}$, have been predicted within the framework of unitary coupled-channel dynamics. In this work, we theoretically investigate the potential to observe these states in the decays ${\Lambda }_b\to J/\psi {\Xi }^{-}{K}^{+}$ and ${\Xi }_b\to J/\psi {\Xi }^{-}{\pi }^{+}$. In this framework, these pentaquark configurations couple strongly to the $J/\psi \Xi$ channel, as well as to other vector-baryon channels with the $\bar{c}cssn$ flavor structure, making these decay modes promising for their observation through the corresponding invariant-mass distributions. Our analysis begins with the identification of the dominant weak decay mechanisms, followed by hadronization into meson-baryon channels, connected through flavor symmetry. Final-state interactions are then incorporated to dynamically generate the full amplitude, accounting for the formation of the pentaquark states. We compare our results with recent LHCb measurements of the $J/\psi {\Xi }^{-}$ mass distribution and find that, given the predicted pentaquark width of about 10 MeV in this channel, the state is too narrow to be resolved with the current experimental resolution, but it would become visible with significantly improved mass precision.

   hep-phEPJC(2026)·6 citations
9. 09*

   Nonlinear dynamics of jet quenching

   Yacine Mehtar-Tani🇺🇸

   We present an analytic framework for jet quenching in dense QCD matter that unifies medium-induced branching with vacuum collinear evolution. Energy transported outside the jet region is governed by a non-linear rate equation that resums arbitrary-angle gluon splittings, each enhanced by the medium length $L$. We show that for asymptotically large energies the energy-loss distribution for a single hard parton exhibits an exponential (generalized Poisson) behavior that provides the initial condition for a non-linear, DGLAP-like evolution that resums collinear logarithms associated with early in-vacuum fragmentation and with the angular resolution of the medium. This framework allows a systematic resummation of parton branching contributions to jet energy loss.

   hep-phnucl-thEPJ Web Conf.(2026)·0 citations
10. 10*

    Dark Matter and Electroweak Baryogenesis with Spontaneous $CP$ Violation in the Early Universe

    Subhojit Roy🇺🇸

    Dark matter (DM) and the baryon asymmetry of the universe (BAU) are among the most compelling indications of physics beyond the Standard Model. We revisit the inelastic Higgs-portal complex singlet, a minimal framework in which a complex scalar splits into two nearly degenerate real states, with an off-diagonal Higgs-portal interaction that drives coannihilation to set the relic density, while the elastic DM-Higgs coupling can be tuned small enough to evade direct-detection limits. This setup naturally supports a strong first-order electroweak phase transition (SFOEWPT) and can account for the long-standing Galactic Center gamma-ray excess (GCE) via present-day DM annihilation into Higgs pairs. In this work, we show that the same framework, extended by a $Z_2$-symmetric dimension-6 $CP$-violating top Yukawa operator, can also generate the BAU via the electroweak baryogenesis (EWBG) mechanism. The cosmological history involves a two-step electroweak phase transition: first, the singlet fields acquire nonzero vacuum expectation values (vevs); then a strongly first-order transition occurs in which the Higgs develops its nonzero vev while the singlet vevs vanish. During this second step, both fields remain nonzero only within the advancing bubble wall, generating wall-localized $CP$ violation that biases sphaleron transitions and enables EWBG. After the phase transition, $CP$ and $Z_2$ symmetries are restored: the lightest singlet state becomes a stable DM candidate, while the vanishing singlet vevs allow the model to naturally satisfy the stringent constraints on $CP$ violation. We delineate the SFOEWPT-favored parameter space, identifying the criteria for the two-step phase transition region that simultaneously yields the observed BAU and relic density, explains the GCE, and predicts gravitational wave spectra accessible to next-generation space-based detectors.

    hep-phastro-ph.COhep-exPRD(2026)·8 citations
11. 11*

    Belle II Constraints on the Non-Minimal Universal Extra Dimensional Model

    Avirup Shaw🇮🇳

    Recent measurements by the Belle II Collaboration report a branching ratio for the decay $B^{+}\to K^{+}\nu \bar{\nu }$ with a 3.5$\sigma$ significance and deviating by 2.7$\sigma$ from Standard Model expectation. In this article, we interpret this experimental result through the lens of a Non-minimal Universal Extra Dimensional model, where the mass profiles and interactions among various Kaluza-Klein states differ remarkably from those in the minimal scenario. Our analysis indicates that, according to the model's parameters, the lower limit on the inverse of the compactification radius has been elevated to approximately 900 GeV. In contrast, conducting the same analysis within the model variant in which all boundary terms are nullified does not permit the determination of a lower bound on the inverse compactification radius.

    hep-phPRD(2026)·4 citations
12. 12*

    Studies on Response Uniformity of RPC and Exploring Oscillation Dip and Valley, Non-Standard Interactions, and Earth's Core using Atmospheric Neutrinos at ICAL-INO detector

    Anil Kumar🇮🇳

    In this thesis, experimental and physics simulation studies are performed in the context of the proposed 50 kt Iron Calorimeter (ICAL) detector at the India-based Neutrino Observatory (INO). ICAL would detect atmospheric muon neutrinos and antineutrinos separately in the multi-GeV range of energies over a wide range of baselines. In the experimental part of the thesis, the effect of the non-uniformity of the graphite layer on the detector response of the resistive plate chamber is studied. In the physics simulation part, it is demonstrated for the first time that the neutrino oscillation dip and valley can be observed at ICAL using the up/down ratio of reconstructed muons and antimuons separately. A method is formulated such that the location of the dip and the alignment of the valley can be used to measure an atmospheric oscillation parameter called the mass-squared difference. Further, a new approach is proposed to probe the neutral-current non-standard interactions (NSIs) using the oscillation dip and valley. The opposite shifts in the oscillation dips and the contrast in the curvatures of oscillation valleys for reconstructed muons and antimuons are used to constrain the NSI parameter in two separate ways. While passing through the Earth, the upward-going atmospheric neutrinos experience the matter effects, which modify the neutrino oscillation patterns. These matter effects depend upon the density of electrons inside Earth and can be used to perform the neutrino oscillation tomography of Earth, complementary to gravitational measurements and seismic studies. This work demonstrates that the presence of Earth's core can be validated using the atmospheric neutrinos at ICAL.

    hep-phhep-exphysics.ins-det1 citation
13. 13*

    There is no 690 GeV resonance

    James M. Cline🇨🇦

    In a series of $\sim 30$ papers starting in 1991, it has been claimed that the Higgs field should be heavier than its now-measured value. To reconcile this idea with reality, it was modified to the assertion that the Higgs field describes two physical degrees of freedom, one of which corresponds to a second Higgs particle with mass 690 GeV. Here I summarize the lack of theoretical and experimental evidence for these claims.

    hep-phNPB(2026)·2 citations
14. 14*

    Configuration and Benchmarking of ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$ Processes with K4GeneratorsConfig

    Alan Price🇵🇱 · Dirk Zerwas🇩🇪

    The next generation of electron-positron colliders will require unprecedented precision in both theory and experiment. Sophisticated software frameworks are essential to evaluate detector concepts, optimize designs, and simulating physical processes. In this context, Monte Carlo (MC) event generators play a central role, enabling realistic simulations of Standard Model processes and providing the basis for physics studies. However, technical consistency across different generators remains critical, particularly in domains where agreement is expected. To address this need, we present K4GeneratorsConfig, a Python-based package that automates the benchmarking process for MC generators. The tool translates universal physics inputs into generator-specific configurations, ensuring consistency, reproducibility, and reduced human error. Its modular design allows for straightforward integration of additional generators, supports batch processing, and provides compatibility with the Key4hep software stack

    hep-phhep-exEPJC(2026)·2 citations
15. 15*

    Gravitational waves from high-temperature vacuum decay in scale-invariant models: nanohertz vs. millihertz regimes

    Ahmad Mohamadnejad🇮🇷

    We present a comprehensive analysis of high-temperature vacuum decay and the resulting stochastic gravitational wave (GW) background within the framework of general scale-invariant models. The effective potential is constructed to include tree-level contributions, the Coleman-Weinberg correction, finite-temperature effects, and the Daisy resummation technique, culminating in a high-temperature form. We investigate the dynamics of the first-order phase transition, calculating the critical and nucleation temperatures, the supercooling parameter, and the key transition parameters $\alpha$ (transition strength) and $\beta$ (inverse duration). The vacuum decay is found to be dominated by sphaleron transitions rather than quantum tunneling. We compute the full GW spectrum arising from bubble collisions, sound waves, and turbulence. An extensive numerical scan reveals two distinct phenomenological regimes: one produces nanohertz-frequency GW signals potentially detectable by Pulsar Timing Arrays (PTA), while the other yields millihertz-frequency signals that are prime targets for future space-based interferometers like the Laser Interferometer Space Antenna (LISA).

    hep-ph0 citations
16. 16*

    Effect of Cosmic Neutrino Background on the Dark Matter Self-interaction via Neutrino force

    Pawin Ittisamai🇹🇭 · Chakrit Pongkitivanichkul🇹🇭 · Muhammaddaniya Sutwilai🇹🇭 · Nakorn Thongyoi🇹🇭 · Patipan Uttayarat🇹🇭

    Neutrino-pair exchange induces a neutrino force that can drive dark matter (DM) self-interactions and impact small-scale structure formation. In the presence of the cosmic neutrino background (C$\nu$B), this force can be modified, with important consequences for DM phenomenology. We study the effect of the C$\nu$B on neutrino forces, generated by the scalar and pseudoscalar interactions. We explore the significance of the background neutrino force on the scalar DM-neutrino portal model, including DM self-scattering and annihilation. Our results show that the interplay between attractive vacuum potential and repulsive background potential leads to a screening effect that varies across DM mass ($m_{\chi }$) regimes, strongly affecting DM self-scattering in the DM mass $m_{\nu }\lesssim m_{\chi }\lesssim T_{C\nu B}$. Meanwhile, for DM annihilation, the screening completely vanishes the Sommerfeld Enhancement induced by the neutrino force. Overall, the C$\nu$B substantially reshapes the viable coupling range for DM self-interactions while remaining compatible with current constraints, offering a pathway to small-scale structure problems.

    hep-phJHEP(2026)·2 citations
17. 17*

    Numerical evaluation of parton distribution Mellin moments

    Akbari Jahan🇮🇳 · Diptimonta Neog🇮🇳

    The detailed comprehension of momentum fraction and energy dependence of proton structure functions is among the major difficulties in high-energy physics. Perturbative quantum chromodynamics (QCD) plays as an extensive foundation for analysing deep inelastic scattering (DIS) and experiments with hadron-hadron collisions. In such a framework, where the hard collisions advance through the partonic components of hadrons, a pivotal contribution is imparted by parton distribution functions (PDFs). PDFs provide information about the nucleonic substructure in terms of its components. PDFs have become more and more convictive following the advent of the Large Hadron Collider (LHC). Moments of PDFs are important quantities for the analysis of hadronic internal structure. The Mellin moments of such parton densities have been discussed and their analyses have been carried out numerically.

    hep-phPhysics(2024)·0 citations
18. 18*

    Tensor spin polarization induced by curved freeze-out hypersurface

    Zhong-Hua Zhang🇨🇳 · Xu-Guang Huang🇨🇳

    We investigate how the curvature of the freeze-out hypersurface polarizes massive vector bosons in relativistic heavy-ion collisions. Starting from the Proca Lagrangian and using the Wigner function formalism, we perform a systematic gradient expansion to obtain a covariant spin-polarization tensor expressed in terms of hydrodynamic fields and the curvature tensor of the freeze-out hypersurface. Analytic results for Bjorken and Gubser flows show that curvature anisotropy generates a nonzero tensor polarization. For $\varphi$ meson, we estimate the curvature contribution to its spin alignment as $\delta {\Theta }_{yy}\sim -10^{-4}$ to $-10^{-3}$. We also find that the curvature contribution grows as the system size decreases. A rough estimate for central O-O collisions gives a spin alignment of order $-10^{-2}$, suggesting that spin-alignment measurements in such small systems may provide a clean probe of this geometric effect.

    hep-phnucl-thPRD(2026)·2 citations
19. 19*

    Theory overview on polarization and spin-correlations in multi-boson processes

    Thi Nhung Dao🇻🇳 · Duc Ninh Le🇻🇳

    In this contribution, we summarize and discuss recent theoretical progress on the Standard-Model calculation of joint polarized cross sections of massive multi-boson processes with fully leptonic decays. The topics include fixed-order calculation of higher order QCD and electroweak corrections for both production and decay amplitudes, and parton-shower effects.

    hep-phhep-exPoS(2026)·0 citations
20. 20*

    Collinear Structure of Nonlinear Small-$x$ Evolution

    Renaud Boussarie🇫🇷 · Paul Caucal🇫🇷 · Yacine Mehtar-Tani🇺🇸

    We introduce a novel approach to high-energy QCD factorization of cross-sections for processes involving a dilute projectile and a dense target. Our method preserves the factorization between "fast" and "slow" modes in the longitudinal momentum $k^{+}$ for a projectile moving along the positive light-cone direction, making it compatible with higher-order loop computations done within the standard formulation of the Color Glass Condensate (CGC) effective field theory. Moreover, it eliminates the anomalous double collinear logarithms that typically hinder the convergence of perturbation theory at small-$x$. Our scheme amounts to a change of basis in the space of CGC operators, introducing an arbitrary transverse scale dependence while leaving physical cross-sections invariant. Implementing this scheme requires a modification of the high-energy renormalization group equation for the CGC operators, which we explicitly derive at next-to-leading order (NLO) and in the non-linear regime for the case of the dipole operator and the DIS impact factor. This general framework provides a consistent and systematic prescription for computing observables in the small-$x$ regime of QCD, free from collinear instabilities.

    hep-phhep-thnucl-th9 citations
21. 21*

    Studies of beauty hadron and non-prompt charm hadron production in pp collisions at $\sqrt{s}$=13 TeV within a transport model approach

    Jialin He🇨🇳 · Xinye Peng🇨🇳 · Xiaoming Zhang🇨🇳 · Liang Zheng🇨🇳

    In high-energy proton proton ($pp$) collisions at the LHC, non-prompt charm hadrons, originating from beauty hadron decays, provide a valuable probe for beauty quark dynamics, particularly at low transverse momentum where direct beauty measurements are challenging. We employ A Multi-Phase Transport Model (AMPT) of string melting version coupled with PYTHIA8 initial conditions to study the beauty hadron and non-prompt charm hadron productions in $pp$ collisions at $\sqrt{s}=13$ TeV. In this work, the beauty quark mass during the generation stage has been increased to reproduce the measured $b\bar{b}$ cross section, and a beauty flavor specific coalescence parameter $r_{BM}^b$ is introduced to match LHCb measurements of beauty baryon to meson ratios. With these refinements, AMPT achieves a reasonable agreement with experimental data on beauty hadron yields and non-prompt charm hadron production from ALICE and LHCb. We present the transverse momentum and multiplicity dependence of non-prompt to prompt charm hadron ratios, providing new insights into the interplay between beauty quark production and hadronization process. We emphasize that the multiplicity dependence of the non-prompt to prompt charm hadron productions can be useful to constrain the flavor dependences of the coalescence dynamics. This work establishes a unified framework for future studies of heavy quark transport and collective flow behavior in small collision systems.

    hep-phhep-exnucl-thPRD(2026)·1 citation
22. 22*

    Probing Beyond the Standard Model Scenarios in Long-baseline and Astrophysical Neutrino Experiments

    Sudipta Das🇮🇳

    Over the past few decades, outstanding progress in the neutrino experiment frontier has greatly advanced our understanding of the flavor oscillations of active neutrinos. The remaining key questions such as the neutrino mass ordering, the presence of CP violation in the lepton sector, and the octant of ${\theta }_{23}$ are expected to be resolved in the coming years. The current precise knowledge of neutrino mass and mixing parameters, together with the promising prospects of next-generation neutrino experiments, provides a unique opportunity to test scenarios beyond the Standard Model (BSM) through neutrino oscillation phenomena. This thesis investigates several such BSM scenarios and examines the capability of the next-generation neutrino experiments to probe them.

    hep-phhep-exphysics.ins-det1 citation
23. 23*

    Dark matter: red or blue?

    A. Acar🇬🇧 · C. Isaacson🇬🇧 · M. Bashkanov🇬🇧 · D.P. Watts🇬🇧

    We report the first calculation of light scattering on heavy dark matter (DM) particles. We show that despite the fact that DM has no direct coupling to photons, the light-DM($\gamma \chi$) ($m_{\chi }\sim 1$ TeV) cross-section is non-vanishing, albeit small. The cross section, calculated within the Standard Model (SM) framework, is particularly large in the case of heavy Weakly Interacting Massive Particles (WIMP). Combined with astrophysical observation, these results can constrain existing WIMP DM models in favor of lighter DM, $M_{\chi }<<M_{\mathrm{Planck}}$, (axions, composite DM, etc..) or non-weakly interacting pure gravitational DM. We also show that the energy dependence of light scattering on dark matter should make the DM colored - red in the case of weak-DM and blue for the gravitational-DM, when a white background light is passing through. Gravitational scattering of light on DM particles also leads to non-trivial polarization effects, which might be easier to detect than the deflection of light from the scattering on DM particles, $\gamma \chi \to \gamma \chi$.

    hep-phastro-ph.HEPLB(2025)·2 citations
24. 24*

    Searching for sub-eV Sterile Neutrinos in Neutrino Telescopes

    Emilse Cabrera🇧🇷 · Miaochen Jin🇺🇸 · Carlos A. Argüelles🇺🇸 · Arman Esmaili🇧🇷

    With the forthcoming deployment of IceCube-Upgrade, unprecedented statistics of atmospheric neutrinos in the energy range (1-100) GeV will become available, providing a valuable opportunity to probe physics beyond the Standard Model in the neutrino sector. In this study, we calculate the sensitivity of the IceCube-Upgrade to sterile neutrinos with mass-squared splittings $\lesssim 1{\mathrm{eV}}^2$. We demonstrate that, particularly due to the (1-10) GeV energy window, ${\nu }_{\mu }-{\nu }_s$ mixing angles as small as $\sim 5^{\circ }$ can be probed by IceCube-Upgrade for all mass-squared splittings below $1{\mathrm{eV}}^2$. Furthermore, we investigate the potential impact of a sterile neutrino state on the precision determination of standard atmospheric neutrino mixing parameters in the IceCube-Upgrade.

    hep-phPRD(2026)·3 citations
25. 25*

    Gravitational Waves from Hyperbolic Encounters of Primordial Black Holes in Dwarf Galaxies

    Tadeo D. Gòmez-Aguilar🇲🇽 · Encieh Erfani🇨🇦 · N. M. Jimènez Cruz🇬🇧

    We investigate the stochastic gravitational wave background (SGWB) generated by primordial black holes (PBHs) in the dense cores of dwarf galaxies (DGs), considering both hierarchical binary black hole (BBH) mergers and close hyperbolic encounters (CHEs). Extending our previous merger framework, we incorporate up to four successive generations of PBHs within a Hubble time and quantify the GW emission from both channels. Our results show that while BBHs dominate the total emission, CHEs occur earlier, provide the first GW signals, and contribute a continuous though subdominant background that becomes relatively more significant once the initial PBH population is depleted and binary formation is suppressed. We compute the resulting SGWB spectra, demonstrating that BBHs and CHEs imprint distinct frequency dependencies consistent with analytical expectations. We then compare the predicted signals with the sensitivity of observatories such as LISA, DECIGO, ET, IPTA, and SKA. The numerical implementation is publicly available at \href{https://github.com/TadeoDGAguilar/PBHs_and_GWs_into_DG}.

    ↳ astro-ph.COhep-phJCAP(2026)·1 citation
26. 26*

    Anisotropic momentum distributions due to radiation recoil in relativistic plasmas with electric and magnetic fields

    Haidar Al-Naseri🇺🇸

    The interaction of strong electromagnetic fields with plasma generates radiation accompanied by a recoil force, which can significantly alter the plasma dynamics. In this work, we investigate the development of anisotropic momentum distributions induced by the combined action of electric and magnetic fields on a thermally relativistic plasma. We consider three distinct types of anisotropy. The first arises from a pure magnetic field acting on plasma with either isotropic or anisotropic initial momentum distributions, producing the characteristic ring-shaped momentum profile. The second is driven by a pure electric field, where radiation reaction generates a partial, anisotropic ring distribution in momentum space: significant modifications occur primarily in the 90${}^{\circ }$--180${}^{\circ }$ and 270${}^{\circ }$--360${}^{\circ }$ sectors of the $p_x$--$p_y$ plane, while the remaining quadrants remain largely unaffected. The third case considers the combined effect of electric and magnetic fields. When the cyclotron frequency is very close to the upper hybrid frequency, the azimuthal symmetry of the ring-momentum distribution is broken. Conversely, in the regime where the cyclotron frequency is lower than the upper hybrid frequency, the rapid oscillations of the electric field dominate and preserve the symmetry of the ring-momentum distribution.

    ↳ physics.plasm-phhep-phphysics.comp-ph0 citations
27. 27*

    Amplituhedra for generic quantum processes via the TQNN representation of UQC

    Chris Fields🇺🇸 · James F. Glazebrook🇺🇸 · Antonino Marcianò🇨🇳 · Emanuele Zappala🇺🇸

    We study the relationship between computation and scattering both operationally (hence phenomenologically) and formally. We develop a representation of universal quantum computation (UQC) within the formalism of topological quantum neural networks (TQNNs), using the Reshetikhin-Turaev and Turaev-Viro models to show how TQNNs implement quantum error-correcting codes. We then exhibit a formal correspondence between TQNNs and amplituhedra to support the existence of amplituhedra for representing generic quantum processes. This construction shows how amplituhedra are geometric representations of underlying topological structures. We conclude by pointing to applications areas enabled by these results.

    ↳ quant-phhep-phhep-th0 citations
28. 28*

    First Data of the 3000 km${}^2$ Radio Detector at the Pierre Auger Observatory

    Bjarni Pont (for the Pierre Auger Collaboration)🇳🇱

    In this contribution, we present the status and first data from the Radio Detector (RD) at the Pierre Auger Observatory, consisting of $1660$ radio antennas deployed across the $3000$ km${}^2$ surface detector array. These antennas measure the radio emission from extensive air showers in the $30-80$ MHz band, enabling electromagnetic energy measurements for air showers with zenith angles above $65\mathrm{deg}$. Combined with the muonic measurements from the water-Cherenkov detectors (WCDs), this allows mass composition studies at the highest energies. The large-scale deployment of the RD began in November 2023 and was completed in November 2024. A full end-to-end calibration shows consistency between Galactic and in-lab calibration to better than $5$\% and includes continuous monitoring for hardware failures, ensuring, for example, antenna alignment within $5\mathrm{deg}$. We present the first data, demonstrating a strong correlation between the electromagnetic energy measured by the RD and the total shower energy measured by the WCD, confirming that the detector chain - including triggering, data readout, absolute calibration, and reconstruction is well understood. We highlight a particularly impressive $32$ EeV shower at a zenith angle of $85\mathrm{deg}$, producing a $50$ km-long radio footprint, showcasing the unique capabilities of this detector.

    ↳ astro-ph.IMhep-ph1 citation
29. 29*

    Directly Probing Neutrino Interactions through CMB Phase Shift Measurements

    Gabriele Montefalcone🇺🇸 · Subhajit Ghosh🇺🇸 · Kimberly K. Boddy🇺🇸 · Daven Wei Ren Ho🇺🇸 · Yuhsin Tsai🇺🇸

    Perturbations in the cosmic neutrino background produce a characteristic phase shift in the acoustic oscillations imprinted in the anisotropies of the cosmic microwave background (CMB), providing a unique observational probe of neutrino physics. In this work, we explore how this phase shift signature is altered in the presence of neutrino interactions with temperature-dependent scattering rates, motivated by physical constructions for neutrino self-interactions and neutrino-dark matter couplings. A key finding is that the phase shift in these realistic models -- characterized by gradual rather than instantaneous decoupling -- maintains the same functional form as the free-streaming template, with only the asymptotic amplitude decreasing for stronger interactions that delay decoupling. This simple parametrization enables us to directly constrain neutrino interactions through phase shift measurements in the temperature and polarization power spectra from CMB observations. Analyzing the latest data from \textit{Planck}, the Atacama Cosmology Telescope, and the South Pole Telescope, we derive strong constraints on the neutrino decoupling redshift. Our global analysis indicates that neutrinos have been freely streaming since deep within the radiation-dominated epoch. We also explore flavor-dependent scenarios in which only one neutrino species interacts. Overall, our work establishes a signature-driven framework that exploits the clean phase shift signal in the acoustic oscillations of the CMB as a precise and robust probe of non-standard neutrino interactions in the early universe.

    ↳ astro-ph.COhep-phhep-thPRD(2026)·11 citations
30. 30*

    Plasma lens with frequency-dependent dispersion measure effects on fast radio bursts

    Yu-Bin Wang · Xia Zhou🇨🇳 · Abdusattar Kurban

    Radio signals propagating through inhomogeneous plasma media deviate from their original paths, producing frequency-dependent magnification effects. In this paper, after reviewing the classical plasma-lensing theory, we have found a fundamental contradiction: the classical model assumes that the distribution of lensing plasma medium is related to the frequency-independent image position; however, our analysis demonstrates that both the image position ($\theta (\nu )$) and dispersion measure (DM$(\nu )$) are inherently frequency-dependent when signals traverse a structured plasma medium. We have been able to resolve this paradox by developing a framework that explicitly incorporates frequency-dependent dispersion measures (DMs) following power-law relationships ($\mathrm{DM}\propto {\nu }^{\gamma }$). Our analysis shows that the signal magnification decreases systematically with decreasing frequency, offering a plausible explanation for the frequency-dependent peak flux densities observed in fast radio bursts (FRBs), particularly in the case of the repeating FRB 180814.J0422+73. Our results suggest these FRBs could originate from the magnetized compact star magnetospheres. By considering these plasma-lensing effects on the sub-pulses of an FRB across different frequencies, we have the ability to more accurately investigate the intrinsic properties of FRBs via precise measurements of radio signals.

    ↳ astro-ph.HEhep-phAstron.Astrophys.(2025)·2 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.