Thu·Oct 2, 2025Thursday·October 2, 2025

1. 01*

   Neutrino backgrounds in matter-wave interferometry: implications for dark matter searches and beyond-Standard Model physics

   João Paulo Pinheiro🇪🇸

   We present a comprehensive theoretical analysis of neutrino-induced decoherence in macroscopic matter-wave interferometry experiments designed to search for dark matter and beyond-Standard Model physics. Our calculation includes contributions from the cosmic neutrino background (C$\nu$B), solar neutrinos, and reactor antineutrinos, accounting for coherent scattering processes across nuclear, atomic, and macroscopic length scales. Within the Standard Model, we find negligible decoherence rates for planned experiments such as MAQRO ($s/{\sigma }_s\sim 10^{-27}$) and terrestrial interferometers like Pino ($s/{\sigma }_s\sim 10^{-22}$). However, these experiments achieve competitive sensitivity to beyond-Standard Model physics through light vector mediator interactions, with C$\nu$B constraining coupling products to $g_{\nu }{g}_n\lesssim 10^{-17}$ for $Z^{\prime }$ masses below 1 eV. Our results provide a theoretical framework for interpreting matter-wave interferometry measurements in terms of neutrino interaction physics and for deriving constraints on BSM models from experimental data.

   hep-phhep-exquant-phJHEP(2026)·1 citation
2. 02*

   Pion bremsstrahlung in the splitting function formalism and the dark photon production

   Dmitry Gorbunov🇷🇺 · Ekaterina Kriukova🇷🇺

   We study the production of hypothetical vector portal mediators, dark photons ${\gamma }^{\prime }$, with masses in the range 0.4-3.5 GeV in the negatively charged pion-proton collisions ${\pi }^{-}p\to {\gamma }^{\prime }X$ via inelastic pion bremsstrahlung and QCD Drell-Yan-like process. In both cases we estimate the value of total dark photon production cross section and obtain the energy distribution for dark photons that could be produced in the NA64h experiment. We also present the mean energies of dark photons produced in the same way by the secondary pions with momenta typical for T2K, DUNE and SHiP experiments.

   hep-phJHEP(2026)·1 citation
3. 03*

   Lepton polarization dependent angular observables and the polarization asymmetries in the four-fold ${\Lambda }_b\to \Lambda (\to N\pi ){\ell }^{+}{\ell }^{-}$ decay

   Rana Khan🇵🇰 · Faisal Munir Bhutta🇵🇰 · Ishtiaq Ahmed🇵🇰 · M. Jamil Aslam🇵🇰

   The rare decays mediated by flavor-changing neutral current processes, such as $b\to s{\ell }^{+}{\ell }^{-}$, provide powerful probes of the Standard Model and potential windows into new physics. Particularly, the angular observables in these exclusive decays are valuable because of their sensitivity to short-distance dynamics and their reduced dependence on hadronic uncertainties, which mainly arise from form factors. In this work, we analyze the ${\Lambda }_b\to \Lambda (\to N\pi ){\ell }^{+}{\ell }^{-}$ (with $N\pi =\{p{\pi }^{-},n{\pi }^0\}$) decay with polarized final-state lepton and derive the corresponding four-fold differential decay distributions. For the longitudinal, normal, and transverse polarization states, we systematically identify the additional angular coefficients that emerge relative to the unpolarized case. We find that the longitudinal polarization preserves the structure of the unpolarized distribution, while the normal and transverse polarizations introduce some new additional angular coefficients. The analytical expressions of all polarized and unpolarized angular coefficients are explicitly derived in terms of the helicity and transversity amplitudes. To compare the variation in the polarized and unpolarized angular observables, we have plotted them against the square of the momentum transfer $q^2$. Additionally, the Standard Model predictions of the polarization asymmetry observables are provided and their sensitivity to new physics is explored under different new physics scenarios. The obtained results, in the current study, for longitudinal and transverse polarization cases, provide a baseline for the lepton polarization dependent observables, which may serve as sensitive probes to test the Standard Model in these decays.

   hep-phNPB(2026)·1 citation
4. 04*

   Scaling properties of nuclear parton distributions in short-range-correlation motivated two-component parametrization

   Petja Paakkinen🇫🇮

   We provide some critical remarks on the recently proposed two-component parametrization of nuclear parton distribution functions, which was motivated by the apparent correlation between the nuclear modifications of structure functions and nucleon-nucleon short-range correlation phenomena. This parametrization, we show, is invariant under a rescaling transformation of the involved abundance coefficients, which means that the global normalization of these coefficients cannot be meaningfully determined in a fit, and only their ratios should be studied for finding evidence of short-range-correlation type behavior at parton level. As we show, however, the current constraints for the nuclear-mass dependence of these coefficients allow also for interpretations different from short-range correlations. Nevertheless, this two-component parametrization exhibits a similar scaling relation for DIS structure functions as demonstrated in earlier works, and, as we demonstrate, yields testable predictions for structure-function and hard-process cross-section ratios. We also note on the non-trivial isospin dependence of the short-range-correlation motivated parametrization, which under proton-neutron pair dominance assumption can lead to charge-symmetry-violation resembling terms.

   hep-phnucl-thPRD(2026)·4 citations
5. 05*

   ELENA: a software for fast and precise computation of first order phase transitions and gravitational waves production in particle physics models

   Francesco Costa🇨🇿 · Jaime Hoefken Zink🇵🇱 · Michele Lucente🇮🇹 · Silvia Pascoli🇮🇹 · Salvador Rosauro-Alcaraz🇮🇹

   We present ELENA (EvaLuator of tunnElliNg Actions), an open-source Python package designed to compute the full evolution of first-order phase transitions in the early Universe generated by particle physics models, taking into account several refinements that go beyond commonly assumed simplifications. The core of ELENA is based on a vectorized implementation of the tunnelling potential formalism, which allows for a fast computation of the finite-temperature tunnelling action. This, in turn, enables the sampling of the full range of temperatures where two phases coexist and the use of integral expressions that track the complete evolution of the transition, providing a comprehensive picture of it. In addition, ELENA provides all the tools to compute the resulting stochastic gravitational waves spectrum, allowing for the full chain of computations - from the Lagrangian parameter inputs to the final gravitational waves spectrum - in a fast and self-contained implementation.

   hep-phastro-ph.COEPJC(2026)·11 citations
6. 06*

   The (3+1)-dimensional scalar field model analysis of beam spin asymmetry in the electroproduction of a scalar meson off a scalar target

   Andrew Lundeen (North Carolina State U.)🇺🇸 · Chueng-Ryong Ji (North Carolina State U.)🇺🇸 · Yongwoo Choi (Inha U.)🇰🇷 · Ho-Meoyng Choi (Kyungpook National U.)🇰🇷

   We explore exclusive scalar meson electroproduction off a scalar target in the (3+1)-dimensional scalar field model. This model analysis is a straightforward extension of the previous (1+1)-dimensional model analysis presented in Phys. Rev. D \textbf{105}, 096014 (2022). In contrast to the (1+1)-dimensional model, the (3+1)-dimensional model allows us to compute the beam spin asymmetry (BSA), which is proportional to the imaginary part of the product of the two Compton form factors (CFFs) that appear in the hadronic current of the present scalar meson electroproduction process. We compute both real and imaginary parts of the CFFs and note that the BSA is detectable for $-t/Q^2\gtrsim 0.1$ although it gets quite small in the kinematic region $-t/Q^2\ll 0.1$ where the factorization of the generalized parton distribution (GPD) is attainable. We find the analytic forms of the leading twist GPD for the DGLAP and ERBL regions in the (3+1)-dimensional scalar field model, confirming its uniqueness independent of the hadronic current component. While we verify that the GPD sum rule for the total result of summing the DGLAP and ERBL regions holds for all components of the hadronic current, we note that the respective correspondence of the DGLAP and ERBL regions to the valence and non-valence parts of the electromagnetic form factor holds only for the light-front plus component of the hadronic current but not for any other components of the hadronic current. We discuss the polynomiality of the GPD up to the second moments and remark on accessible ranges of kinematics to measure the BSA and CFFs with respect to the future experimental efforts of extracting the leading-twist GPDs.

   hep-phPRD(2026)·0 citations
7. 07*

   ${\bar{B}}_{s,d}^0\to J/\psi {\mu }^{+}{\mu }^{-}$ Decays in QCD Factorization

   Xin-Qiang Li🇨🇳 · Yan Shi🇨🇳 · Ya-Dong Yang🇨🇳 · Xing-Bo Yuan🇨🇳 · Chun-Yang Zhao🇨🇳

   Motivated by the first LHCb searches for the rare ${\bar{B}}_{s,d}^0\to J/\psi {\mu }^{+}{\mu }^{-}$ decays, we perform a detailed study of these processes within the QCD factorization formalism. Since the transverse size of the $J/\psi$ meson is small in the heavy quark mass limit, this formalism is generally expected to hold for these decays. We include both the leading- and next-to-leading-order QCD corrections to the hard-scattering kernels, which are convoluted with the light-cone distribution amplitudes (LCDAs) of the initial- and final-state hadrons. It is numerically found that, depending on the model parameters for the leading-twist $B$-meson LCDA, the maximum branching ratios of ${\bar{B}}_s^0\to J/\psi {\mu }^{+}{\mu }^{-}$ and ${\bar{B}}_d^0\to J/\psi {\mu }^{+}{\mu }^{-}$, integrated over the dimuon invariant mass squared $q^2$ from $1{\mathrm{GeV}}^2$ to $(m_{B_{s,d}}-m_{J/\psi }{)}^2$, can reach up to $2.21\times 10^{-9}$ and $7.69\times 10^{-11}$ at the leading order in ${\alpha }_s$, respectively. After incorporating the non-factorizable one-loop vertex corrections, these branching ratios are further reduced by about one order of magnitude, with $\mathcal{B}({\bar{B}}_s^0\to J/\psi {\mu }^{+}{\mu }^{-}){|}_{q^2\ge 1{\mathrm{GeV}}^2}=2.88\times 10^{-10}$ and $\mathcal{B}({\bar{B}}_d^0\to J/\psi {\mu }^{+}{\mu }^{-}){|}_{q^2\ge 1{\mathrm{GeV}}^2}=1.07\times 10^{-11}$. In addition, we have presented the dimuon invariant mass distributions of the individual and total helicity amplitudes squared, as well as the differential and integrated longitudinal polarization fractions of the $J/\psi$ meson, which could be probed by the future LHCb and Belle II experiments with more accumulated data.

   hep-phhep-exJHEP(2026)·0 citations
8. 08*

   Study of spin states in vacuum pair production via the Dirac-Heisenberg-Wigner formalism

   R. Z. Jiang🇨🇳 · Z. L. Li🇨🇳 · Y. J. Li🇨🇳

   A general spin-resolved momentum distribution of electron-positron pairs produced in strong external fields is derived by combining the covariant spin projection operator and the Dirac-Heisenberg-Wigner (DHW) formalism. The result shows that the spin-resolved and helicity-resolved momentum distributions given in previous literature are actually two special cases of it. For any spin-direction unit vector, numerical investigations demonstrate that when the $z$-component of the unit vector vanishes, the number density of produced spin-up and spin-down particles is equal, while their momentum distributions have some asymmetry. For a nonzero $z$-component of the unit vector, there is a difference of $1-3$ orders of magnitude in the number density of spin-up and spin-down particles induced by angular momentum transfer in multiphoton absorption. Moreover, as the electric field strength increases and/or the field frequency decreases, the asymmetry between the spin-up and spin-down particle number density decreases rapidly. These results offer an approach to study general spin states in vacuum pair production, and enhance our understanding of angular momentum transfer from fields to matter in extreme environments.

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

   Enhancing pair production with optimized chirped laser fields

   Z. L. Li🇨🇳 · Y. F. Chen🇨🇳 · R. Z. Jiang🇨🇳 · Y. J. Li🇨🇳

   The optimal chirped field for enhancing electron-positron (EP) pair production is explored using a quantum kinetic approach. First, the momentum spectrum and number density of EP pairs produced by Gaussian chirped fields are investigated. The results show that the momentum spectrum exhibits distinct interference patterns, while the number density grows monotonically with chirp parameters but oscillates with the carrier angular frequency. Moreover, the number density increases by four orders of magnitude compared to chirp-free fields. The results are further compared with those from four other chirped fields: frequency-modulated, linear, quadratic, and sinusoidal chirp. The analysis reveals that the maximum number density for sinusoidally chirped fields is the highest, followed by Gaussian, frequency-modulated, quadratically, and linearly chirped fields. This ranking also applies to the maximum enhancement factors for these chirped fields. Notably, the number density for sinusoidally chirped fields improves nine orders of magnitude compared to chirp-free fields. These results not only deepen our understanding of pair production in chirped fields but also provide significant optimization strategies for future vacuum pair production experiments.

   hep-phquant-ph0 citations
10. 10*

    Phenomenology of a Kinetic Higgs Portal

    Anisha🇩🇪 · Lisa Biermann🇨🇭 · Christoph Englert🇬🇧 · Margarete Mühlleitner🇩🇪

    We explore the phenomenological consequences of non-minimal hidden sector interactions on observable correlations in the Higgs sector, mediated through the ${\mathbb{Z}}_2$-symmetric Higgs portal. Particular attention is given to non-standard momentum dependencies of the hidden sector scalar, which arise naturally in an effective field theory (EFT) framework, e.g. in Composite Scalar Dark Matter theories. We discuss the implications of such hidden sector interactions for the thermal history of the universe. We show that aspects of such non-standard momentum dependencies can be probed at future lepton colliders such as a FCC-ee, potentially also through radiative corrections. This gives rise to precision probes for regions where direct detection constraints and relic abundance can be accounted for as predicted in, e.g., Composite Scalar Dark Matter theories.

    hep-phJHEP(2026)·1 citation
11. 11*

    Mass Varying Neutrino Oscillation in Scalar-Gauss-Bonnet Gravity

    H. Mohseni Sadjadi🇮🇷 · H. Yazdani Ahmadabadi🇮🇷

    We investigate how matter density affects neutrino oscillations by considering a mass-varying neutrino scenario where the neutrino mass depends on a scalar field. This scalar field is non-minimally coupled to the Gauss-Bonnet (GB) invariant, causing its profile to be implicitly influenced by the surrounding matter distribution. Using data from solar neutrino experiments, we derive constraints on the model parameters, providing new insights into the properties of mass-varying neutrino within the Gauss-Bonnet scalar-tensor framework.

    hep-phgr-qchep-thPLB(2025)·3 citations
12. 12*

    Assessment of the $a_2(1320)$ tensor-meson contribution to $\eta /{\eta }^{\prime }\to {\pi }^0\gamma \gamma$ decays

    Rafel Escribano🇪🇸 · Sergi Gonzàlez-Solís🇪🇸 · Emilio Royo🇪🇸

    In light of the recent measurement of the $\eta \to {\pi }^0\gamma \gamma$ decay by the KLOE-2 Collaboration, a previous analysis including vector- and scalar-meson exchange contributions using the VMD and L$\sigma$M frameworks, respectively, is extended in the present study to incorporate the effects of the $a_2(1320)$ tensor meson within a chiral context. Although the individual contribution of the $a_2$ is negligible, its destructive interference with the vector-meson resonances is found to be significant, representing approximately $18\%$ of the total signal and substantially affecting the diphoton invariant-mass distribution, especially at low $m_{\gamma \gamma }^2$ values. The total decay rate is calculated to be $\Gamma (\eta \to {\pi }^0\gamma \gamma )=0.154(22)$ eV, which corresponds to a branching ratio of $\mathrm{BR}(\eta \to {\pi }^0\gamma \gamma )=1.17(17)\times 10^{-4}$. This result is approximately $5\sigma$ below the reported value of the PDG, $2.55(22)\times 10^{-4}$, while it is in very good agreement with the KLOE-2 measurement, $0.98(11_{\mathrm{stat}})(14_{\mathrm{syst}})\times 10^{-4}$. In contrast, the total contribution of the $a_2$ is found to be negligible in ${\eta }^{\prime }\to {\pi }^0\gamma \gamma$, as this process is completely dominated by the exchange of an on-shell $\omega$ vector resonance.

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

    Comparative insights into gluon and proton structure through parton distribution functions

    Akbari Jahan🇮🇳 · Diptimonta Neog🇮🇳

    Study of parton distribution functions (PDFs) has led to a finer cognisance of the structure of partons in hadrons and the proton structure functions in deep inelastic scattering (DIS). PDFs are instrumental in predicting results for most of the hard-scattering processes measured at the Large Hadron Collider (LHC). However, due to the non-perturbative nature of partons, calculation of parton distributions using perturbative QCD (Quantum Chromodynamics) cannot be done. The analysis of PDFs, therefore, needs a relentless effort. In this paper, we study a comparative approach of three global PDF sets, viz. CT14, MMHT2014 and NNPDF 4.0. Gluon distribution functions and proton structure functions have been evaluated in a wide range of momentum fraction \textit{x} and energy scale \textit{Q}; and plausible observations have been made.

    hep-phPhys.Essays(2025)·1 citation
14. 14*

    Gluon Condensation as a Unifying Mechanism for Special Spectra of Cosmic Gamma Rays and Low-Momentum Pion Enhancement at the Large Hadron Collider

    Wei Zhu🇨🇳 · Jianhong Ruan🇨🇳 · Xurong Chen🇨🇳 · Yuchen Tang🇨🇳

    Decoding the internal structure of the proton is a fundamental challenge in physics. Historically, any new discovery about the proton has fuelled advances in several scientific fields. We have reported that gluons inside the proton accumulate near the critical momentum due to chaotic phenomena, forming gluon condensation. Surprisingly, the pion distribution predicted by this gluon distribution for the production of high-energy proton collisions could answer two puzzles in astronomy and high-energy physics. We find that during ultrahigh-energy cosmic ray collisions, gluon condensation may abruptly produce a large number of low-momentum pions, whose electromagnetic decays have the typical breakout properties appearing in various cosmic gamma-ray spectra. On the other hand, the Large Hadron Collider (LHC), which is well below the cosmic ray energy scale, also shows weak but recognisable signs of gluon condensation, which had been mistaken for BEC pions. The connection between these two phenomena, which occur at different scales in the Universe, supports the existence of a new structure within the proton-gluon condensation.

    hep-phastro-ph.HEnlin.CDnucl-thSymmetry(2025)·0 citations
15. 15*

    No Track left behind: Graph-based Vertexing for long-lived Particle Reconstruction

    Jonathan Kriewald🇸🇮

    Reconstruction of displaced vertices is a cornerstone of both precision flavour physics and searches for long-lived particles (LLPs) at colliders. While existing vertexing algorithms are highly optimised for primary and short-lived secondary vertices, they face limitations when confronted with the large displacements and heterogeneous topologies characteristic of LLP decays. In this work we present a new approach to displaced vertex reconstruction combining a graph-based track clustering strategy as a vertex finder with the established robust vertex fitting procedure. The algorithm is implemented as a self-contained Delphes module and can be straightforwardly integrated into existing detector cards, providing a turn-key tool for phenomenological studies. This plug-and-play functionality fills an important gap in public fast-simulation frameworks by providing automated pattern recognition for displaced vertex finding, while remaining readily usable in phenomenological studies. We validate our approach in an IDEA-like FCC-ee detector, using Higgs-strahlung $e^{+}{e}^{-}\to Zh$ with exotic $h\to NN$ decays as a benchmark process. We demonstrate excellent efficiency, resolution, and purity across a broad range of lifetimes, and derive model-independent projections for the FCC-ee sensitivity to exotic Higgs branching fractions.

    hep-phhep-ex1 citation
16. 16*

    Nonperturbative fluctuation effects of charged bosonic fields: A quark-diquark model study at nonzero density

    Jonas Stoll🇩🇪 · Niklas Zorbach🇩🇪 · Jens Braun🇩🇪

    We study the renormalization group flow of the scale-dependent effective potential of a quark-diquark model with full field dependence at nonzero chemical potential. This includes a discussion of approximations in relation to complex bosonic fields and the Silver-Blaze property. The resulting flow equation for the scale-dependent effective potential can in principle be solved down to the infrared limit. For our quark-diquark model, which may serve as a low-energy model for dense strong-interaction matter, we find that a competition between the Bardeen-Cooper-Schrieffer singularity and bosonic fluctuations can trigger a first-order phase transition at low temperatures that turns into a second-order phase transition at a tricritical point as the temperature increases.

    hep-phcond-mat.supr-connucl-th7 citations
17. 17*

    CP violation in the hyperon decays $\Sigma \to N\pi$

    Xiao-Gang He🇨🇳 · Xiao-Dong Ma🇨🇳 · Jusak Tandean🇨🇳 · German Valencia🇦🇺

    The study of $CP$ violation in hyperon transitions has a long history. In the early 2000s the HyperCP experiment made a major effort to seek $CP$-odd signals in the decay sequence ${\Xi }^{-}\to \Lambda {\pi }^{-}$ and $\Lambda \to p{\pi }^{-}$, which motivated more searches. Most recently the BESIII and LHCb Collaborations have acquired or improved the upper bounds on $CP$ violation in a variety of hyperon nonleptonic processes, including ${\Sigma }^{+}\to n{\pi }^{+}$ and ${\Sigma }^{+}\to p{\pi }^0$. These measurements have not reached the standard-model level yet, but have stimulated a renewed interest in $CP$-violating new physics in strange-quark decay beyond what is constrained by the parameters $\epsilon$ and ${\epsilon }^{\prime }$ from the kaon sector. In this paper, after updating the standard-model expectations for $CP$-odd observables in the modes ${\Sigma }^{\pm }\to N\pi$, we revisit new-physics scenarios that could enhance the corresponding quantities in $\Lambda \to N\pi$ and $\Xi \to \Lambda \pi$ and apply them to the ${\Sigma }^{\pm }$ modes. We find that the $CP$ asymmetries in the latter can be significantly increased over the standard-model expectations, at levels which may be tested in the ongoing BESIII experiment and in future endeavors such as PANDA and the Super Tau Charm Facility.

    hep-phhep-exJHEP(2026)·4 citations
18. 18*

    Enhanced Matter Power Spectrum from Axion Kination after Big Bang Nucleosynthesis

    Raymond T. Co🇺🇸 · Nicolas Fernandez🇺🇸 · Akshay Ghalsasi🇺🇸 · Keisuke Harigaya🇺🇸 · Jessie Shelton🇺🇸

    Despite stringent constraints from Big Bang Nucleosynthesis (BBN) and cosmic microwave background (CMB) observations, it is still possible for well-motivated particle physics models to substantially alter the cosmic expansion history between BBN and recombination. In this work we consider two different axion models that can realize a period of first matter domination, then kination, in this epoch. We perform fits to both primordial element abundances as well as CMB data and determine that up to a decade of late axion domination is allowed by these probes of the early universe. We establish the implications of late axion domination for the matter power spectrum on the scales $1/\mathrm{Mpc}\lesssim k\lesssim 10^3/$Mpc. Our 'log' model predicts a relatively modest bump-like feature together with a small suppression relative to the standard $\Lambda$CDM predictions on either side of the enhancement. Our 'two-field' model predicts a larger, plateau-like feature that realizes enhancements to the matter power spectrum of up to two orders of magnitude. These features have interesting implications for structure formation at the forefront of current detection capabilities.

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

    Robust bounds on MACHOs from the faintest galaxies

    Peter W. Graham🇺🇸 · Harikrishnan Ramani🇺🇸 · Maximilian Ruhdorfer🇺🇸

    We use the dynamical heating of stars in ultrafaint dwarf (UFD) galaxies to set limits on Massive Compact Halo Objects (MACHOs). In our analysis we study the robustness of the bounds under uncertainties in key UFD parameters, such as the half-light radius, stellar velocity dispersion, total halo mass and dark matter and stellar density profiles. We apply this framework to both well-established UFD candidates, as well as the recently discovered UFD candidate Ursa Major III/UNIONS 1. We find that multiple UFDs yield consistently strong limits in the mass range $10M_{\odot }\lesssim M_{\mathrm{MACHO}}\lesssim 10^9{M}_{\odot }$, underscoring the robustness of a previous analysis solely based on Segue I. We also demonstrate that Ursa Major III, if confirmed as an UFD, would improve the constraints significantly, providing the strongest constraints on MACHO dark matter in the mass range $1M_{\odot }\lesssim M_{\mathrm{MACHO}}\lesssim 10^5{M}_{\odot }$.

    hep-phastro-ph.COastro-ph.GAPRD(2026)·6 citations
20. 20*

    Boltzmann Suppressed Ultraviolet Freeze-in

    Nicolás Bernal🇦🇪 · Sagnik Mukherjee🇺🇸 · James Unwin🇺🇸

    If the dark matter mass $m$ exceeds the maximum temperature of the Universe ($T_{\max }<m$), then its production rate will be Boltzmann suppressed. The important implications of this Boltzmann suppression have been explored for dark matter freeze-in via renormalizable operators. Here we extend these considerations to the case of ultraviolet (UV) freeze-in for which freeze-in proceeds via non-renormalizable operators. The UV freeze-in variant has a number of appealing features, not least that a given effective field theory can describe a multitude of UV completions, and thus such analyses are model agnostic for a given high dimension freeze-in operator. We undertake model independent analyses of UV freeze-in for portal operators of general mass dimensions. Subsequently, we explore a number of specific examples, namely, Higgs portals, bino dark matter, and gravitino dark matter. Finally, we discuss how significant differences arise if one departs from the standard assumptions regarding inflationary reheating (i.e. transitions from an early matter dominated era to radiation domination). As a motivated example we examine the implications of early kination domination. Boltzmann suppressed UV freeze-in is well motivated and permits a number of compelling scenarios. In particular, we highlight that for $T_{\max }\sim$ 1 TeV it is feasible that the freeze-in mechanism is entirely realized within a couple of orders of magnitude of the TeV scale, making it experimentally accessible in contrast to traditional freeze-in scenarios.

    hep-phastro-ph.COJCAP(2026)·13 citations
21. 21*

    Updated Running Quark and Lepton Parameters at Various Scales

    Stefan Antusch🇨🇭 · Kevin Hinze🇨🇭 · Shaikh Saad🇸🇮

    In the light of the recent Particle Data Group (PDG) release, we revisit the running quark and lepton Yukawa couplings, together with the quark mixing parameters, across a range of energy scales. The 2024 PDG determinations of low-energy fermion masses feature significantly smaller uncertainties, resulting from a reduced estimate of systematic errors compared to the more conservative treatment in the 2022 analysis. To assess the impact of these changes, we present running parameters obtained using both the 2022 and 2024 datasets, within the frameworks of the Standard Model (SM) and its minimal supersymmetric extension (MSSM). The evolved values, along with their associated $1\sigma$ uncertainties, are given within the SM framework at benchmark scales of $M_Z$ and $10^3$, $3\cdot 10^3$, $10^4$, $10^5$, $10^7$, $10^9$, $10^{12}$, and $10^{16}$ GeV. Within the MSSM, we additionally provide GUT-scale results for different choices of $\tan \beta$, assuming supersymmetry breaking scales of 3 and 10 TeV, including an approximate way for taking supersymmetric loop threshold corrections into account. We furthermore discuss implications of the updated results for constructing and testing theories beyond the SM.

    hep-phPRD(2026)·23 citations
22. 22*

    Dark Drag Around Sagittarius A*

    Javier F. Acevedo🇺🇸 · Aidan J. Reilly🇺🇸 · Lillian Santos-Olmsted🇺🇸

    We analyze the effect of Dark Matter (DM) - Standard Model (SM) non-gravitational interactions on the orbital dynamics of celestial bodies near the supermassive black hole Sagittarius A*, where the DM density is generically expected to be high. We outline the conditions under which a DM-SM scattering channel gives rise to a drag force on objects in this region, and show that for sufficiently large cross-sections, this effect can lead to observable orbital decay on timescales as short as a single orbital period. We identify the types of objects most strongly affected by this dark drag and place constraints on specific dark matter distributions and interaction strengths, assuming both elastic and inelastic scattering. For inelastic DM, we find sensitivity to mass splittings that reach the MeV scale. We also demonstrate that a DM-induced drag force could potentially contribute to the observed depletion of red giant branch stars in the innermost region of the Milky Way.

    hep-phastro-ph.COastro-ph.HE15 citations
23. 23*

    SN 2025coe: A Multiple-Peaked Calcium-Strong Transient from A White-Dwarf Progenitor

    Chun Chen · Ning-Chen Sun · Qiang Xi🇨🇳 · Samaporn Tinyanont · David Aguado · Ismael Pérez-Fournon · Frédérick Poidevin🇪🇸 · Justyn R. Maund · Amit Kumar🇨🇦 · Junjie Jin · Yiming Mao🇨🇳 · Beichuan Wang🇺🇸 and 16 other authors

    SN 2025coe is a calcium-strong transient located at an extremely large projected offset $\sim$39.3 kpc from the center of its host, the nearby early-type galaxy NGC 3277 at a distance of $\sim$25.5 Mpc. In this paper, we present multi-band photometric and spectroscopic observations spanning $\sim$100 days post-discovery. Its multi-band light curves display {multiple} distinct peaks: (1) an initial peak at $t\approx 1.6$ days attributed to shock cooling emission, (2) a secondary peak of $M_{R,peak}\approx$ $-$15.8 mag at $t\approx 10.2$ days powered by radioactive decay, and (3) a {possible} late-time bump at $t\approx 42.8$ days likely caused by ejecta-circumstellar material/clump interaction. Spectral evolution of SN 2025coe reveals a fast transition to the nebular phase within 2 months, where it exhibits an exceptionally high [Ca II]/[O I] ratio larger than 6. Modeling of the bolometric light curve suggests an ejecta mass of $M_{\mathrm{ej}}=0.29_{-0.15}^{+0.14}{M}_{\odot }$, a ${}^{56}$Ni mass of $M_{{}^{56}\mathrm{Ni}}=2.4_{-0.05}^{+0.06}\times 10^{-2}{M}_{\odot }$, and a progenitor envelope with mass $M_e=1.4_{-1.2}^{+6.9}\times 10^{-3}{M}_{\odot }$ and radius $R_e=13.5_{-11.1}^{+64.1}{R}_{\odot }$. The tidal disruption of a hybrid HeCO white dwarf (WD) by a low-mass CO WD provides a natural explanation for the low ejecta mass, the small fraction of ${}^{56}$Ni, and the presence of an extended, low-mass envelope.

    ↳ astro-ph.HEastro-ph.GAhep-phApJ(2026)·5 citations
24. 24*

    Lectures on Open Effective Field Theories

    Thomas Colas🇬🇧

    Effective field theories offer a powerful method to unify diverse models under a small set of control parameters, allowing systematic expansions around well-established theories. These techniques, developed in particle physics, were designed for experiments where the initial state - the vacuum before a scattering event - is as clean and isolated as possible. Besides colliders, realistic environments are often noisy and dissipative. The recognition of the limitations of traditional EFT techniques has, over the past decade, sparked intense progress at the interface of high-energy physics and condensed matter. These considerations motivate a new approach to gravitation and cosmology, one that models the gravitational sector as evolving in the presence of an unobservable medium. Open Effective Field Theories provide a systematic and controllable field-theoretic framework for modeling dissipation and noise in gravitation and cosmology. These notes aim to introduce this versatile toolkit, enabling model-agnostic assessments of how unknown environments shape our observational probes.

    ↳ hep-thastro-ph.COgr-qchep-ph13 citations
25. 25*

    Limiting the Parameter Space for Unstable eV-scale Neutrinos Using IceCube Data

    R. Abbasi · M. Ackermann · J. Adams · S. K. Agarwalla · J. A. Aguilar · M. Ahlers · J.M. Alameddine · S. Ali · N. M. Amin · K. Andeen · C. Argüelles · Y. Ashida and 413 other authors

    This Letter extends a recent IceCube sterile neutrino search to include unstable sterile neutrinos within the context of a model termed 3+1+Decay, which expands upon the 3+1 model by introducing sterile neutrino decay to invisible particles with coupling constant $g^2$. The model is attractive since it reduces tension between oscillation experiments within the global fits and with constraints that come from cosmological observables. The analysis uses 10.7 years of up-going muon neutrino data with energy 500 GeV to 100 TeV and with improved reconstruction and modeling of systematics. The best-fit point is found to be $g^2=0$, ${\sin }^2(2{\theta }_{24})=0.16$, and $\Delta m_{41}^2=3.5$ eV${}^2$, in agreement with the recent 3+1 sterile neutrino search. Values of $g^2\ge \pi$ are excluded at 95\% confidence level. This result substantially limits decay parameter space indicated by recent global fits, disfavoring the decay scenario.

    ↳ hep-exhep-phPRL(2026)·1 citation
26. 26*

    The Evolution of Pop III.1 Protostars Powered by Dark Matter Annihilation. II. Dependence on WIMP Properties

    Konstantinos Topalakis🇸🇪 · Devesh Nandal🇺🇸 · Jonathan C. Tan🇨🇳

    The rapid appearance of supermassive black holes (SMBHs) at $z\gtrsim 7$ requires efficient pathways to form massive black hole seeds. We investigate whether annihilation of weakly interacting massive particles (WIMPs) can alter primordial (Pop III.1) protostellar evolution sufficiently to enable formation of such `heavy'' seeds. Using the one-dimensional Geneva stellar-evolution code (GENEC) with an implemented Gould single-scatter capture module, we compute a grid of protostellar evolution models covering ambient WIMP mass densities ${\rho }_{\chi }=10^{12}$-$10^{16}\mathrm{GeV}\mathrm{c}{\mathrm{m}}^{-3}$, WIMP masses $m_{\chi }=30$-$3000\mathrm{GeV}$, spin-dependent cross sections ${\sigma }_{\mathrm{SD}}=10^{-42}$-$10^{-40}\mathrm{c}{\mathrm{m}}^2$, and baryonic accretion rates $\dot{M_{\ast }}=(1-3)\times 10^{-3}{M}_{\odot }{\mathrm{yr}}^{-1}$. We find a robust bifurcation of outcomes. For sufficiently high ambient dark matter density (${\rho }_{\chi }\gtrsim 5\times 10^{14}\mathrm{GeV}\mathrm{c}{\mathrm{m}}^{-3}$) and capture efficiency (${\sigma }_{\mathrm{SD}}\gtrsim 10^{-41}\mathrm{c}{\mathrm{m}}^2$) WIMP annihilation supplies enough energy to inflate protostars onto extended, cool (Hayashi-track) configurations that dramatically suppress ionizing feedback and permit uninterrupted growth to $\sim 10^5{M}_{\odot }$. Lighter WIMPs and larger ${\sigma }_{\mathrm{SD}}$ favour earlier and stronger annihilation support; heavier WIMPs delay the effect. For our fiducial case, WIMP masses $<$3 TeV are essential for allowing growth to the supermassive regime, otherwise the protostar evolves to the compact, feedback-limited regime that results in `light'' seeds. These results indicate that, under plausible halo conditions, DM annihilation provides a viable channel for forming heavy black hole seeds.

    ↳ astro-ph.GAastro-ph.COastro-ph.HEastro-ph.SR+14 citations
27. 27*

    Relativistic hydrodynamics with spinodal decomposition

    Joseph Kapusta🇺🇸 · Mayank Singh🇺🇸 · Thomas Welle🇺🇸

    We introduce the equations of relativistic hydrodynamics that incorporate phase separation via spinodal decomposition. These equations consider surface effects between the two phases and are applicable for simulating intermediate-energy heavy-ion collisions and binary neutron star mergers, where a first-order phase transition is expected. We solve these equations in the context of Bjorken flow, which offers the relevant geometric framework for ion collisions.

    ↳ nucl-thhep-phEPJ Web Conf.(2026)·0 citations
28. 28*

    Shadow of rotating black holes with consistent thermodynamics

    Che-Yu Chen🇯🇵 · Chiang-Mei Chen🇹🇼 · Nobuyoshi Ohta🇰🇷

    Quantum effects in general induce scale dependence in the coupling constants. We explore this possibility in gravity, with a scale-dependent Newton coupling. When applied to Kerr black holes with such a running coupling, the consistency of black hole thermodynamics requires that the Newton coupling have a specific dependence on the black hole parameters. In this work, we consider such a class of Newton couplings and look for the possible observational implications on the highly lensed images of the black holes. In addition to placing constraints on the parameter space of the model through the latest Sgr A* images, we find that the variations in the shape of shadows in a large portion of the parameter space can be qualitatively captured by a quantity solely defined by the event horizon. Most importantly, the consistency of thermodynamics suggests a lower bound on the shadow size, beyond which either horizon disappears, or the shadow cannot keep the standard D-shaped structure. The possibility that the black holes in this model could spin faster than the Kerr bound, and the physical implications of the resulting cuspy shadows, are also discussed.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRD(2026)·9 citations
29. 29*

    Diffraction by Circular and Triangular Apertures as a Diagnostic Tool of Twisted Matter Waves

    Maksim Maksimov · Nikita Borodin · Daria Kargina🇷🇺 · Dmitry Naumov🇷🇺 · Dmitry Karlovets🇷🇺

    We study diffraction of twisted matter waves (electrons and light ions carrying orbital angular momentum $\ell /\hslash =0,\pm 1,\pm 2,\dots$ by circular and triangular apertures. Within the scalar Kirchhoff-Fresnel framework, circular apertures preserve cylindrical symmetry and produce ringlike far-field profiles whose radii and widths depend on $|\ell |$ but are insensitive to its sign. In contrast, equilateral triangles break axial symmetry and yield structured patterns that encode both the magnitude and the sign of $\ell$. A transparent Fraunhofer mapping links detector coordinates to the Fourier plane, explaining the $(|\ell |+1)$-lobe rule and the sign-dependent rotation of the pattern. We validate these results for both ideal Bessel beams and localized Laguerre-Gaussian packets, and we cross-check them by split-step Fourier propagation of the time-dependent Schr"odinger equation. From these analyses we extract practical design rules (Fraunhofer distance, lattice pitch, detector sampling) relevant to OAM diagnostics with moderately relativistic electrons with $E_{\mathrm{kin}}\sim 0.1$ to $5$ MeV and light ions with $E_{\mathrm{kin}}\sim 0.1$ to $1$ MeV/u. Our results establish triangular diffraction as a simple, passive, and robust method for reading out the OAM content of structured quantum beams.

    ↳ quant-phhep-phphysics.acc-phPRA(2025)·5 citations
30. 30*

    Alleviating Cosmological Tensions with the Hadrosymmetric Twin Higgs

    Mohammad Soroori Sotudeh🇮🇷 · Zahra Davari🇰🇷 · Sara Khatibi🇮🇷 · Nima Khosravi🇮🇷

    The Hadrosymmetric Twin Higgs (HTH) model provides a natural solution to the little hierarchy problem by incorporating all three generations of quarks in a twin sector. Unlike other Twin Higgs scenarios, such as the Mirror Twin Higgs (MTH), the HTH framework avoids introducing additional light states or radiation and thus remains consistent with stringent bounds on the effective number of relativistic species, $\Delta N_{\mathrm{eff}}$. Its particle content and interactions also make it difficult to probe at colliders, highlighting the importance of cosmological tests. In this work, we study the cosmological implications of the HTH model, focusing on the persistent tensions in the Hubble constant ($H_0$) and the matter clustering amplitude (${\sigma }_8$). Implementing the HTH sector in a Boltzmann code and confronting it with cosmic microwave background (CMB) data and local $H_0$ measurements, we find that HTH scenario partially reduces the Hubble tension from more than $4\sigma$ to about $2.5\sigma$, while also alleviating the ${\sigma }_8$ discrepancy. These results demonstrate that the HTH framework not only addresses naturalness in particle physics but also offers a viable route to mitigating current cosmological tensions, thereby strengthening the link between fundamental theory and precision cosmology.

    ↳ astro-ph.COhep-phhep-thPRD(2026)·1 citation
31. 31*

    Gravitational Waves sourced by Gauge Fields during Inflation

    Martin Teuscher🇫🇷 · Ruth Durrer🇨🇭 · Killian Martineau🇫🇷 · Aurélien Barrau🇫🇷

    We study the inflationary gravitational wave background induced by Abelian gauge fields generated by non-minimal kinetic and axial couplings to the inflaton. We show that, up to slow-roll corrections, for coupling functions that share the same dependence on conformal time, the gravitational wave spectrum is nearly scale invariant. We also derive its amplitude for generic gauge field coupling parameters, within the slow-roll approximation. The coupling values and the scale of inflation for which the induced gravitational wave background is observable, while ensuring that back-reaction on the inflationary dynamics remains negligible, are calculated. We find that a sizeable axial coupling can boost this secondary gravitational wave signal above the standard inflationary background. In the course of our analysis, we also show how to analytically match tensor perturbations across an arbitrary number of eras with different equations of state.

    ↳ astro-ph.COgr-qchep-phJCAP(2026)·8 citations
32. 32*

    GW250114 reveals black hole horizon signatures

    Neil Lu🇦🇺 · Sizheng Ma🇨🇦 · Ornella J. Piccinni🇦🇺 · Yanbei Chen🇺🇸 · Ling Sun🇦🇺

    The horizon of a black hole, the "surface of no return", is characterized by its rotation frequency ${\Omega }_H$ and surface gravity $\kappa$. A striking signature is that any infalling object appears to orbit at ${\Omega }_H$ due to frame dragging, while its emitted signals decay exponentially at a rate set by $\kappa$ as a consequence of gravitational redshift. Recent theoretical work predicts that the merger phase of gravitational waves from binary black hole coalescences carries direct imprints of the remnant horizon's properties, via a "direct wave" component that (i) oscillates near $2{\Omega }_H$, reflecting the horizon's frame dragging and the dominant quadrupole nature of the gravitational radiation, and (ii) decays at an increasing rate characterized by $\kappa$, with additional screening from the black hole's potential barrier. In this paper, we report observational evidence for the direct wave in GW250114, with a 90\% credible matched-filter signal-to-noise ratio of $15.8_{-0.5}^{+0.1}$ ($17.1_{-0.4}^{+0.1}$) in the LIGO Hanford (Livingston) detector. The measured properties are in full agreement with theoretical predictions. These findings establish a new observational channel to directly measure frame-dragging effects in black hole ergospheres and explore (near-)horizon physics in dynamical, strong-gravity regimes.

    ↳ gr-qcastro-ph.HEhep-phNature(2026)·24 citations
33. 33*

    Vanishing Acts: Quantifying Black Hole Formation with the DSNB Signal

    Tim Charissé🇩🇪 · David Maksimović🇩🇪 · George A. Parker🇩🇪 · Michael Wurm🇩🇪

    The diffuse supernova neutrino background (DSNB) created by stellar core-collapses throughout cosmic history is on the verge of discovery, with SK-Gd showing early deviations from the background expectation and JUNO starting to take data. However, the interpretation of early DSNB data will face significant challenges due to degeneracies between astrophysical parameters and uncertainties in supernova neutrino modeling. We explore how complementary astronomical observations can break these degeneracies and, in this context, we investigate whether early DSNB observations can constrain invisible supernovae, which have no optical emission but are powerful neutrino sources before being swallowed by a forming black hole. Leveraging the differences in the spectra between invisible and visible supernovae, we estimate the sensitivity of 1) detecting the existence of invisible supernovae, and 2) determining the fraction of invisible supernovae. Finally, we discuss how these conclusions depend on the spectral parameters of the black hole-forming component.

    ↳ astro-ph.HEhep-exhep-phphysics.ins-detJCAP(2026)·0 citations
34. 34*

    Cosmological Constraints on Secluded Dark Radiation

    Jae Hyeok Chang🇺🇸 · Peizhi Du🇨🇳 · Subhajit Ghosh🇺🇸 · Soubhik Kumar🇺🇸

    Dark radiation (DR) is ubiquitous in physics beyond the Standard Model (SM), and its interactions with the SM and dark matter (DM) lead to a variety of interesting effects on cosmological observables. However, even in scenarios where DR is 'secluded', i.e., only gravitationally interacting with SM and DM, it can leave discernible signatures. We present a comprehensive study of four different types of DR: free-streaming, self-interacting (coupled), decoupling, and recoupling DR, and vary initial conditions to include both adiabatic and isocurvature perturbations. In addition to these properties, we also vary neutrino energy density, DR energy density, and the SM neutrino masses to perform a general analysis and study degeneracies among neutrino and DR properties. We derive constraints using the cosmic microwave background, large-scale structure, and supernova datasets. We find no significant preference for physics beyond the $\Lambda$CDM model, but data exhibit interesting interplays between different physical quantities. When the neutrino energy density is allowed to vary, we find that the cosmological dataset prefers massless free-streaming DR over massive neutrinos, leading to a significant relaxation of the neutrino mass bound. Although we do not find any evidence of DR isocurvature, the data show support for a strong blue tilt of the isocurvature power spectrum. Our analysis also highlights the degeneracy of various DR parameters with the Hubble constant $H_0$ resulting in a mild relaxation of the $H_0$ tension.

    ↳ astro-ph.COhep-phJCAP(2026)·9 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.