Thu·Oct 16, 2025Thursday·October 16, 2025

1. 01*

   Hadronic vacuum polarization to three loops in chiral perturbation theory

   Laurent Lellouch🇫🇷 · Alessandro Lupo🇫🇷 · Mattias Sjö🇫🇷 · Kálmán Szabo🇩🇪 · Pierre Vanhove🇫🇷

   Hadronic vacuum polarization at low virtualities limits the precision of experimental tests of the standard model via important physical observables. Here we compute that effect in two-flavor chiral perturbation theory to three loops. Among the master integrals that describe the amplitude, six are elliptic functions of the momentum. Of these five are new to this work, although all can be related to the three-loop sunset integral. The renormalizability of the amplitude hinges on relations between the master integrals that were not previously known and that are not consequences of the integration-by-parts reduction. Our result is intended to serve as a starting point for phenomenological calculations, as well as the computation of finite-volume corrections in lattice QCD.

   hep-phhep-lathep-thJHEP(2026)·5 citations
2. 02*

   Updated Constraints on Large Extra Dimensions from Reactor Antineutrino Experiments

   T. Gökalp Elaçmaz · Ivan Martinez-Soler🇬🇧 · Yuber F. Perez-Gonzalez🇪🇸

   We investigate constraints on large extra dimensions (LED) using the latest results from reactor antineutrino experiments. Specifically, we analyze the full data sets from Daya Bay, RENO, KamLAND, NEOS, and STEREO to derive updated bounds. For the case of one extra dimension, we find constrains on its radius $a$ of $a\lesssim 0.58\mu \mathrm{m}$ ($a\lesssim 0.12\mu \mathrm{m}$) at the $99\%$ confidence level for normal (inverted) ordering, an improvement of approximately $\sim 20\%$ ($\sim 25\%$) with respect to previous bounds, assuming a massless lightest active neutrino. Furthermore, we present new limits on $4+d$ LED scenarios, with $d=2,3,4$ denoting the number of extra dimensions, based on the same reactor data and assuming equal radii for all extra dimensions. We find that the constraints become increasingly stringent with a larger number of extra dimensions. In particular, $d=4$ with a massless lightest active neutrino, we obtain limits of $a\lesssim 0.28\mu \mathrm{m}$ for normal and $a\lesssim 0.05\mu \mathrm{m}$ for inverted orderings at the $99\%$ confidence level.

   hep-ph8 citations
3. 03*

   Searching for the QCD critical point through constant entropy density contours

   Hitansh Shah🇺🇸 · Mauricio Hippert🇧🇷 · Jorge Noronha🇺🇸 · Claudia Ratti🇺🇸 · Volodymyr Vovchenko🇺🇸

   We propose a novel method to locate the QCD critical point by constructing an expansion along contours of constant entropy density. Applying two independent analysis of lattice QCD data at zero baryon chemical potential, we find a critical point at $T_c=114\pm 7$ MeV and ${\mu }_{B_c}=602\pm 62$ MeV for an expansion truncated at order ${\mu }_B^2$. This approach is consistent with recent lattice QCD results up to ${\mu }_B/T\le 3$. A more precise determination of the required expansion coefficients from lattice simulations will be essential for reliably establishing the location of the QCD critical endpoint.

   hep-phnucl-thEPJ Web Conf.(2026)·0 citations
4. 04*

   A short review on QCD sum rule studies of P-wave single heavy baryons

   Xuan Luo🇨🇳 · Shu-Wei Zhang🇨🇳 · Hua-Xing Chen🇨🇳 · Atsushi Hosaka🇯🇵 · Niu Su🇨🇳 · Hui-Min Yang🇨🇳

   Over the past few decades, the study of singly heavy baryons has entered a golden era, with numerous excited states observed by experimental collaborations. Various theoretical approaches have been developed to investigate their properties, with the QCD sum rule method being one of the most widely applied. This paper provides a review of these QCD sum rule studies. Over the last ten years, we have systematically studied $P$-wave singly heavy baryons using QCD sum rules and light-cone sum rules within the framework of heavy quark effective theory. These $P$-wave singly heavy baryons can explain many excited heavy baryons, including the ${\Lambda }_c(2595{)}^{+}$, ${\Lambda }_c(2625{)}^{+}$, ${\Xi }_c(2790{)}^{0/+}$, ${\Xi }_c(2815{)}^{0/+}$, ${\Sigma }_c(2800{)}^0$, ${\Xi }_c(2882{)}^0$, ${\Xi }_c(2923{)}^0$, ${\Xi }_c(2939{)}^0$, ${\Xi }_c(2965{)}^0$, ${\Omega }_c(3000{)}^0$, ${\Omega }_c(3066{)}^0$, ${\Omega }_c(3090{)}^0$, ${\Omega }_c(3050{)}^0$, ${\Omega }_c(3119{)}^0$, ${\Lambda }_b(5912{)}^0$, ${\Lambda }_b(5920{)}^0$, ${\Xi }_b(6087{)}^0$, ${\Xi }_b(6095{)}^0/{\Xi }_b(6100{)}^{-}$, ${\Sigma }_b(6097{)}^{\pm }$, ${\Xi }_b(6227{)}^{-}$, ${\Omega }_b(6316{)}^{-}$, ${\Omega }_b(6330{)}^{-}$, ${\Omega }_b(6340{)}^{-}$, and ${\Omega }_b(6350{)}^{-}$, etc. Furthermore, we predict additional $P$-wave singly heavy baryons, including two ${\Lambda }_b$ states, two ${\Xi }_b$ states, three ${\Sigma }_b$ states, three ${\Xi }_b^{\prime }$ states, two ${\Omega }_b$ states, two ${\Lambda }_c$ states, two ${\Xi }_c$ states, three ${\Sigma }_c$ states, and one ${\Omega }_c$ state, all with relatively narrow decay widths, making them viable candidates for experimental observation. The study of singly heavy baryons is closely related to two meaningful questions:"What is the shortest possible lifetime of an observable particle?" and "How can one generally describe approximate (flavor) symmetries?".

   hep-phhep-exhep-thnucl-ex+1AAPPS Bull.(2026)·9 citations
5. 05*

   Coscattering Dark Matter in the Inverse Scotogenic Models

   Ang Liu🇨🇳 · Zhi-Long Han🇨🇳 · Fei Huang🇨🇳 · Feng-Lan Shao🇨🇳 · Wei Wang🇨🇳

   The Scotogenic mechanism is an appealing pathway to naturally explain the common origin of dark matter and tiny neutrino mass. However, the conventional scotogenic dark matter usually suffers stringent constraints from the non-observation of lepton flavor violation and direct detection. To generate the non-zero neutrino masses, at least two generations of dark particles are required. For example, two real scalar singlets ${\varphi }_1$ and ${\varphi }_2$ are involved in the inverse scotogenic model, which are odd under the $Z_2$ symmetry. In this paper, we consider the masses of dark scalars are nearly degenerate $m_{{\varphi }_1}\lesssim m_{{\varphi }_2}$, which opens new viable pathway for the generation of dark matter ${\varphi }_1$, such as the coscattering process ${\varphi }_1\text{SM}\to {\varphi }_2\text{SM}$ and coannihilation processes ${\varphi }_1{\varphi }_2\to \text{SM SM}$ via the Higgs portal or Yukawa portal interactions. We explore the parameter space to produce the correct relic density through coscattering, as well as the contrastive coannihilation channel. We then comprehensively study the constraints of dark matter from Higgs decay, direct detection, and indirect detection. For the heavier dark scalar, the three-body decay ${\varphi }_2\to {\varphi }_{1}f\bar{f}$ not only alerts the predictions of big bang nucleosynthesis and cosmic microwave background, but also leads to the observable displaced vertex signature at colliders.

   hep-phJHEP(2026)·4 citations
6. 06*

   Strange pentaquark molecules in QCD sum rules

   Di Ben🇨🇳 · Sheng-Qi Zhang🇨🇳

   We study hidden- and open-strange pentaquark configurations in the hadronic molecular picture with QCD sum rules. Starting from the baryon octet combined with an $s\bar{s}$ pair, we construct 21 interpolating currents with $J=1/2$ and $3/2$. In the analysis, contributions up to dimension 11 are included in the operator product expansion, and both parity-projected spectra and the chiral-even and chiral-odd Lorentz structures are examined. No bound-state solution is found in the $J^P=1/2^{-}$ sector, although several channels generate resonance masses near nearby thresholds or poorly established strange baryons. In the $J^P=3/2^{-}$ sector, the $\Sigma \varphi$ and $\Xi K^{\ast }$ currents both support a near-threshold bound-state solution around $2.2$ GeV, suggesting a possible molecular configuration with channel mixing. In contrast, positive-parity sectors are more difficult to identify the corresponding states. In addition, our results favor the spin-parity assignments $J^P=3/2^{-}$ for $\Sigma (2250)$, $J^P=1/2^{-}$ for $\Sigma (2455)$, $\Sigma (2620)$, and $\Xi (2370)$, and $J^P=3/2^{+}$ for $\Xi (2250)$. These results provide a systematic QCD sum rule study of strange pentaquark molecular candidates in the strange sector.

   hep-phPRD(2026)·5 citations
7. 07*

   Parton model contributions as next-to-eikonal corrections to the dipole factorization of DIS and SIDIS at low $x_{Bj}$

   Tolga Altinoluk🇵🇱 · Guillaume Beuf🇵🇱 · Swaleha Mulani🇵🇱

   We compute the next-to-eikonal (NEik) power corrections to inclusive deep inelastic scattering (DIS) and semi-inclusive deep inelastic scattering (SIDIS) at low $x$ beyond dipole factorization, which represent the eikonal result. The analysis is restricted to contributions arising from t-channel quark exchanges, thereby probing the quark background field of the target. For a transversely polarized virtual photon, the NEik corrections to inclusive DIS are expressed in terms of quark and antiquark collinear parton distribution functions (PDFs), while the corresponding corrections to SIDIS are formulated in terms of the unpolarized quark transverse-momentum-dependent distribution (TMD). In contrast, for a longitudinally polarized photon, the NEik corrections to both inclusive DIS and SIDIS vanish at lowest order in ${\alpha }_s$.

   hep-phPRD(2026)·12 citations
8. 08*

   Perturbations to $\mu -\tau$ reflection symmetry due to renormalization group running effects

   Chandan Kumar Borah🇮🇳 · Chandan Duarah🇮🇳

   $\mu -\tau$ reflection symmetry is an attractive flavour symmetry in lepton mixing, which accommodates maximal values of atmospheric mixing angle (${\theta }_{23}=\pi /4$) and Dirac CP phase ($\delta =\pi /2/3\pi /2$). Another significance of this symmetry is that it does not constrain ${\theta }_{13}$ to be zero. As the recent results from $T2K$ and $NO\nu A$ experiments indicate a near-maximal value of the Dirac CP phase, the role of $\mu -\tau$ reflection symmetry becomes more prominent. In this work, we study RG running effects as a perturbation to the $\mu -\tau$ reflection symmetry. Assuming the symmetry to be preserved at the seesaw scale, we study the deviations of mass eigenvalues and lepton mixing parameters at the electroweak scale due to RG running. We derive the one-loop RGEs of the mass eigenvalues and mixing parameters and solve them numerically. Numerical analysis shows that the deviations from $\mu -\tau$ reflection symmetry are consistent with $3\sigma$ range of global oscillation data.

   hep-phPTEP(2026)·1 citation
9. 09*

   Flavor Symmetry and Proton Decay in PeV-Scale Supersymmetry

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

   Supersymmetry beyond the TeV scale offers several theoretical and phenomenological advantages, such as accommodating the observed Higgs mass and alleviating the flavor and CP problems. However, flavor and CP observables still impose stringent constraints even at the PeV scale, motivating a systematic study of flavor symmetries in this regime. In this work, we investigate nucleon decay induced by dimension-five operators in supersymmetric standard models and examine how flavor symmetries, particularly of the Froggatt-Nielsen type, can suppress these operators. We perform a Bayesian analysis combining flavor, CP, and proton-decay observables to quantify the allowed parameter space and identify characteristic predictions. Our results demonstrate that a multi-messenger approach, integrating flavor, CP, and baryon-number-violating observables, is essential for probing the underlying structure of supersymmetry beyond the TeV scale.

   hep-phJHEP(2026)·2 citations
10. 10*

    Radiative decays of the $\Omega (2012)$ as a hadronic molecule

    Qing-Hua Shen🇨🇳 · Jun-Xu Lu🇨🇳 · Li-Sheng Geng🇨🇳 · Xiang Liu🇨🇳 · Ju-Jun Xie🇨🇳

    We present a theoretical investigation of the radiative decay process $\Omega (2012)\to \gamma \Omega$, where the $\Omega (2012)$ resonance with spin-parity $J^P={\frac{3}{2}}^{-}$, is treated as a dynamically generated state from $\bar{K}\Xi (1530)$ and $\eta \Omega$ in $s$-wave and $\bar{K}\Xi$ in $d$-wave. The radiative decay width of the $\Omega (2012)$ is calculated using a triangular loop mechanism, where the $\Omega (2012)$ couples to the $\bar{K}\Xi (1530)$ channel. Subsequently, the final state interactions between $\Xi (1530)$ and $\bar{K}$ transition to a photon and $\Omega$ through the exchange of a $\Xi$ baryon. Our calculations yield a radiative decay width of $13.2_{-3.9}^{+4.5}$ KeV, with uncertainties arising from the model parameters. This result provides valuable insights into the nature of the $\Omega (2012)$ resonance and its decay dynamics. It is expected that the calculations presented here could be verified by future experiments, which would open a new door for studying the still elusive nature of the $\Omega (2012)$.

    hep-phPRD(2026)·8 citations
11. 11*

    Analysis of the strong vertices of hadronic molecules $DK$, $D^{\ast }K$, $D{K}^{\ast }$ and their bottom analogs

    Ze Zhou🇨🇳 · Guo-Liang Yu🇨🇳 · Zhi-Gang Wang🇨🇳 · Jie Lu🇨🇳

    In this work, we analyze the strong vertices of hadronic molecules $DK$, $D^{\ast }K$, $D{K}^{\ast }$ and their bottom analogs within the framework of three-point QCD sum rules. The coupling between interpolating currents and low spin particles is considered in the phenomenological side, and the vacuum condensates $⟨\bar{q}q⟩,⟨g_s^{2}GG⟩,⟨\bar{q}{g}_s\sigma Gq⟩,⟨g_s^{3}GGG⟩,{⟨\bar{q}q⟩}^2$ are included in the QCD side. As an application of strong coupling constants, we also obtain the partial decay widths of these states, where ${\Gamma }_{T_{DK}\to D_s\pi }=10.3_{-2.9}^{+3.0}\mathrm{KeV}$, ${\Gamma }_{T_{D^{\ast }K}\to D_s^{\ast }\pi }=24.8_{-5.4}^{+5.5}\mathrm{KeV}$, ${\Gamma }_{T_{BK}\to BK}=101_{-21}^{+36}\mathrm{MeV}$ and ${\Gamma }_{T_{B^{\ast }K}\to B^{\ast }K}=142_{-25}^{+52}\mathrm{MeV}$. It is shown that the results of ${\Gamma }_{T_{DK}\to D_s\pi }$ and ${\Gamma }_{T_{D^{\ast }K}\to D_s^{\ast }\pi }$ are compatible with the experimental data of $D_{s0}^{\ast }(2317)$ and $D_{s1}(2460)$.

    hep-phEPJC(2026)·3 citations
12. 12*

    Unified Origin of Dirac Neutrino and Asymmetric Dark Matter Masses via a Dirac-Type Leptogenesis

    Megumi Ishida🇯🇵 · Hiroshi Ohki🇯🇵 · Shohei Uemura🇯🇵

    We propose a simple and unified framework that simultaneously explains the origins of light Dirac neutrino masses, asymmetric dark matter (ADM), and the baryon asymmetry of the Universe. The model is based on an extended $U(1{)}_X$ Froggatt-Nielsen--like mechanism, which naturally generates suppressed Yukawa couplings and realizes a Dirac seesaw for neutrino masses. An additional ${\mathbb{Z}}_4$ symmetry stabilizes the dark sector, where chiral fermions charged under ${\mathbb{Z}}_4$ serve as ADM candidates. Leptogenesis occurs through the out-of-equilibrium decays of heavy Dirac neutrinos, where the generated asymmetry is shared between the visible and dark sectors due to exact lepton-number conservation. The same suppression mechanism that explains the smallness of neutrino masses also determines the GeV-scale ADM mass. Numerical studies demonstrate that a fully asymmetric DM scenario is realized, consistent with relic abundance, Big Bang nucleosynthesis, and direct detection constraints. This framework provides an experimentally testable connection between neutrino physics, dark matter, and baryogenesis within an anomaly-free setup.

    hep-phastro-ph.COPTEP(2026)·2 citations
13. 13*

    Gauge-independent Gravitational Waves from Cogenesis in a $B-L$ Conserving Universe

    Wan-Zhe Feng🇨🇳 · Jinzheng Li🇺🇸 · Pran Nath🇺🇸 · Zong-Huan Ye🇨🇳

    An analysis of baryogenesis and stochastic gravitational wave production is presented for an extension of the standard model where the dark sector consists of dark matter particles charged under a $U(1{)}_x$ gauge symmetry, while a subset of dark fields also carry lepton number but no $U(1{)}_x$ charge. We demonstrate that with CP violation induced by Yukawa couplings, equal and opposite lepton asymmetries are generated in the visible and hidden sectors. Subsequent evolution preserves lepton number separately in each sector, and sphaleron interactions partially convert the lepton asymmetry into baryon asymmetry near the temperature of the first-order phase transition. Further, we discuss stochastic gravitational wave background production for the first-order phase transition using a gauge-independent bubble nucleation dynamics which yields spectra also valid in the supercooled low-temperature regime with {$T_p/m_{A_x}\ll 1$} where $T_p$ is the percolation temperature and $m_{A_x}$ is the dark photon mass. A parameter-space scan identifies regions that simultaneously account for cogenesis of baryon asymmetry and dark matter and predict stochastic gravitational wave signals within reach of current (NANOGrav, EPTA, PPTA) and future detectors at higher frequencies, providing a unified framework for cogenesis and associated gravitational wave production.

    hep-phPRD(2026)·6 citations
14. 14*

    First simultaneous analysis of transverse momentum dependent and collinear parton distributions in the proton

    P. C. Barry🇺🇸 · A. Prokudin🇺🇸 · T. Anderson🇺🇸 · C. Cocuzza🇺🇸 · L. Gamberg🇺🇸 · W. Melnitchouk🇺🇸 · E. Moffat🇺🇸 · D. Pitonyak🇺🇸 · J.-W. Qiu🇺🇸 · N. Sato🇺🇸 · A. Vladimirov🇪🇸 · R. M. Whitehill🇺🇸

    We present the first simultaneous global QCD analysis of unpolarized transverse momentum dependent (TMD) and collinear parton distribution functions (PDFs) in the proton. Our study incorporates data from deep-inelastic scattering, Drell-Yan, inclusive weak boson, $W$+\,charm, and jet production involving PDFs, as well as TMD Drell-Yan and $Z$-boson production data from fixed target and collider experiments sensitive to both TMD and collinear distributions. The analysis is performed at next-to-next-to-leading logarithmic accuracy for QCD resummation in TMD observables and next-to-leading order for observables described in collinear factorization. The combined analysis improves knowledge of both TMD and collinear PDFs, particularly in the sea-quark sector, providing a consistent simultaneous description of the aforementioned observables.

    hep-phhep-exhep-latnucl-th19 citations
15. 15*

    A new effective field theory for heavy quarks in the quark-gluon plasma

    Andreas Kirchner🇺🇸 · Berndt Müller🇺🇸 · Jyotirmoy Roy🇺🇸 · Chathuranga Sirimanna🇺🇸

    An effective field theory framework is developed to study the interaction of heavy quarks in strongly coupled quark-gluon plasma (QGP). The latter is treated as a relativistic non-dissipative colorless fluid which can be studied using a derivatively coupled effective field theory based on previous work. Coupling this to heavy quarks provides a systematic way to obtain the interaction between the heavy quark and phonons, excitations of the fluid. In particular we calculate the quasiparticle width of heavy quark to phonon and phonon-heavy quark scattering in a thermal medium.

    hep-phnucl-thJHEP(2026)·0 citations
16. 16*

    Probing Quadratically Coupled Ultralight Dark Matter with Pulsar Timing Arrays

    Xucheng Gan🇩🇪 · Hyungjin Kim🇩🇪 · Andrea Mitridate🇩🇪

    Ultralight dark matter may couple quadratically to Standard Model particles. Such quadratic interactions give rise to both coherent and stochastic signals in pulsar timing array (PTA) observations. In this work, we characterize these signals, including the effects of dark matter propagation in a finite-density medium, and assess the sensitivity of current and upcoming PTA observations to their detection. For coherent signals, we find that the sensitivity of current PTA observations competes with and sometimes exceeds that of other probes, such as equivalence principle tests and atomic clocks. For stochastic signals, we find that PTA sensitivities underperform equivalence principle constraints for both existing and upcoming PTA data sets.

    hep-phastro-ph.COPRD(2026)·19 citations
17. 17*

    Large Neutrino "Collider"

    Yang Bai🇺🇸 · Keping Xie🇺🇸 · Bei Zhou🇺🇸

    We propose using current and future large-volume neutrino telescopes as ``Large Neutrino Colliders" (L$\nu$Cs) to explore TeV-scale physics beyond the Standard Model. Cosmic neutrinos with energies above 100 PeV colliding with nucleons in the detector reach center-of-mass energies beyond the 14 TeV limit of the Large Hadron Collider (LHC). Using recently predicted and measured high-energy and ultra-high-energy neutrino fluxes from IceCube and KM3NeT, we estimate mass-scale sensitivities for representative new physics scenarios at 1--30 km${}^3$ L$\nu$Cs. Our results demonstrate that L$\nu$Cs provide a novel avenue to probe multi-TeV particles with sensitivities comparable to, or even surpassing, those of the LHC.

    hep-phastro-ph.HEhep-ex6 citations
18. 18*

    Decoherence in high energy collisions as renormalization group flow

    Jiayin Gu🇨🇳 · Shi-Jia Lin🇨🇳 · Ding Yu Shao🇨🇳 · Lian-Tao Wang🇺🇸 · Si-Xiang Yang🇨🇳

    The unification of quantum information science and collider physics is opening a new frontier in high-energy experiments, making a systematic understanding of decoherence a critical challenge. We present a framework to systematically compute spin decoherence from final-state radiation by combining soft-collinear effective theory and open quantum system techniques. We demonstrate that the renormalization group (RG) evolution of the final-state spin density matrix constitutes a quantum channel, where the RG flow parameter, rather than time, drives a Markovian loss of quantum information. Our approach incorporates explicit detector resolution parameters, allowing a direct connection between experimental capabilities and the preservation of quantum coherence. Applying this formalism to a fermion pair ($f\bar{f}$) in the high-energy limit with QED-like final-state radiation, we provide the first systematically RG-improved prediction for decoherence as a function of experimental resolution, revealing the underlying decoherence mechanism to be a phase-flip channel. This work establishes an essential theoretical tool for future precision measurements of quantum phenomena in high-energy collisions and offers a new perspective on the interplay between RG flow and decoherence of open quantum systems.

    hep-phhep-exquant-ph30 citations
19. 19*

    Positivity and partial wave unitarity bounds on ALP theories via amplitude methods

    Luigi C. Bresciani🇮🇹 · Gabriele Levati🇨🇭 · Paride Paradisi🇮🇹

    We derive the complete set of partial wave unitarity bounds on the most general Axion-Like Particle (ALP) effective interactions up to dimension 8 in the limit of large center-of-mass energy. Exploiting a recently developed formalism based on spinor-helicity techniques, we discuss the unitarity bounds for $N\to M$ (with $N,M\ge 2$) scattering amplitudes that can be relevant for ALP searches at colliders or in a variety of rare processes. Moreover, we compute positivity bounds on ALP interactions, emphasizing their complementarity with partial wave unitarity bounds. As a byproduct, we show that our results can be used to infer new positivity constraints in the Standard Model Effective Field Theory.

    hep-phJHEP(2026)·7 citations
20. 20*

    No cosmological constraints on dark photon dark matter from resonant conversion: Impact of nonlinear plasma dynamics

    Anson Hook🇺🇸 · Junwu Huang🇨🇦 · Mohamad Shalaby🇨🇦

    We revisit and invalidate all dark photon dark matter constraints from resonant conversion of dark photons into photons (plasmons) in the early universe. These constraints rely on the resonant transfer of a substantial portion of the dark photon energy density into the SM plasma, heating the plasma in the process. We demonstrate that this resonant transfer saturates because of plasma nonlinearities. Dark photon dark matter resonantly converts into $k\simeq 0$ Langmuir waves in the early universe electron-ion plasma. Once the Langmuir-wave energy approaches the thermal energy of the plasma, nonlinear effects driven by the ponderomotive force become significant. In particular, we show using dedicated Particle-in-Cell simulations that large-amplitude $k=0$ Langmuir waves excite higher-k Langmuir and ion acoustic waves, producing strong spatial variations in density and plasma frequency. These inhomogeneities suppress further resonant conversion, limiting the deposited energy to about the thermal energy of the electrons at the time of conversion, orders of magnitude below observable cosmological thresholds. Consequently, the dark photon dark matter constraints are weaker by factors of $3000$ to $10^7$ across ten orders of magnitude in dark photon mass.

    hep-phastro-ph.COphysics.plasm-phPRL(2026)·8 citations
21. 21*

    Light new physics and the $\tau$ lepton dipole moments: prospects at Belle II

    Martin Hoferichter🇨🇭 · Gabriele Levati🇨🇭

    While electron and muon dipole moments are well-established precision probes of physics beyond the standard model, it is notoriously challenging to test realistic new-physics (NP) scenarios for the $\tau$ lepton. Constructing suitable asymmetries in $e^{+}{e}^{-}\to {\tau }^{+}{\tau }^{-}$ has emerged as a promising such avenue, providing access to the electric and magnetic dipole moment once a polarized electron beam is available, e.g., with the proposed polarization upgrade of the SuperKEKB $e^{+}{e}^{-}$ collider. However, this interpretation relies on an effective-field-theory (EFT) argument that only applies if the NP scale is large compared to the center-of-mass energy. In this Letter we address the consequences of the asymmetry measurements in the case of light NP, using light spin-0 and spin-1 bosons as test cases, to show how results can again be interpreted as constraints on dipole moments, albeit in a model-dependent manner, and how the decoupling to the EFT limit proceeds in these cases. In particular, we observe that the imaginary parts generated by light new particles can yield nonvanishing asymmetries even without electron polarization, which can again be interpreted as constraints on the $\tau$ anomalous magnetic moment. This proposed measurement, thus, presents a novel opportunity for NP searches that can be realized already with present data at Belle II.

    hep-phhep-exnucl-thPRL(2026)·11 citations
22. 22*

    Isospin-based EWP-tree Relations

    Bhubanjyoti Bhattacharya🇺🇸 · Marianne Bouchard🇨🇦 · Alexandre Jean🇨🇦 · David London🇨🇦 · Ipsita Ray🇨🇦

    In 1998, it was shown that, if flavor SU(3) symmetry [SU(3)${}_F$] is assumed in charmless $B\to PP$ decays ($P$ is a light pseudoscalar meson), some reduced matrix elements involving electroweak penguin (EWP) operators are related to those involving tree operators. Similarly, EWP diagrams are related to tree diagrams. These SU(3)${}_F$ EWP-tree relations were recently used in global analyses of $B\to PP$ decays. They have also been used over the years in analyses of the $B\to \pi K$ puzzle, even though the $B\to \pi K$ amplitudes are related by isospin symmetry [SU(2)${}_I$], and not the full SU(3)${}_F$. In this paper, we show that, even if only SU(2)${}_I$ is assumed, there are still EWP-tree relations. In $\Delta S=0$ decays, these relations are similar to those of SU(3)${}_F$, and can be used to take into account the EWP contributions in the extraction of the CP phase $\alpha$ from $B\to \pi \pi$ decays. In $\Delta S=1$ decays, the SU(2)${}_I$ EWP-tree relations are quite different from those of SU(3)${}_F$; when these are used to analyze the $B\to \pi K$ puzzle, one now finds a 4-5$\sigma$ discrepancy with the Standard Model, much larger than what was previously found. We argue that, if one analyzes a set of hadronic $B$ decays whose amplitudes are related by isospin, one must use the SU(2)${}_I$ EWP-tree relations for that set of decays in the analysis.

    hep-phJHEP(2026)·7 citations
23. 23*

    Absence of Majorana-Weyl fermions in d=4 and the theory of Majorana fermions

    Kazuo Fujikawa🇯🇵

    It is customary to identify ${\psi }_{+}={\nu }_R+C{\overline{{\nu }_R}}^T$ with a Majorana fermion on the basis of chirality changing charge conjugation $\tilde{C}:{\nu }_R\to C{\overline{{\nu }_R}}^T$ and parity $\tilde{P}:{\nu }_R\to i{\gamma }^0{\nu }_R$. The theorem on the absence of a Majorana-Weyl fermion in $d=4$ states $\tilde{C}{\gamma }_5{\tilde{C}}^{-1}=-{\gamma }_5$ with $\tilde{C}=C{\gamma }_4^T$, and thus the charge conjugation of the equivalent Majorana ${\psi }_{+}=(\frac{1+{\gamma }_5}{2}){\nu }_R+(\frac{1-{\gamma }_5}{2})C{\overline{{\nu }_R}}^T$ vanishes without subsidiary ${\gamma }_5\to -{\gamma }_5$, namely, not defined in field theory. To be consistent with the theorem, it is common to use a doublet representation of chirality preserving charge conjugation $\hat{C}:{\nu }_{R,L}\to C{\overline{{\nu }_{L,R}}}^T$ and parity $\hat{P}:{\nu }_{R,L}\to i{\gamma }^0{\nu }_{L,R}$ in theory containing both ${\nu }_{R,L}$. In the type I seesaw model, the latter formulation is applicable but ${\psi }_{+}={\nu }_R+C{\overline{{\nu }_R}}^T$ is not a Majorana fermion. An analogue of the Bogoliubov transformation converts ${\psi }_{\pm }={\nu }_{R,L}\pm C{\overline{{\nu }_{R,L}}}^T$, which are obtained by a precise diagonalization of the seesaw model, to Majorana fermions ${\psi }_{M_{1,2}}=(\psi \pm C{\overline{\psi }}^T)/\sqrt{2}$ with a Dirac-type fermion $\psi$, as originally defined by Majorana. A chiral projection $[(1+{\gamma }_5)/2]{\psi }_{M_1}$ of a Majorana fermion is not a chiral fermion, which ensures the presence of the neutrino-less double beta decay.

    hep-phPRD(2026)·1 citation
24. 24*

    When Tiny Halos Stir Spacetime: Gravitational Waves from Fifth-Force Mergers

    Xinpeng Wang🇯🇵 · Yifan Lu🇺🇸 · Zachary S. C. Picker🇺🇸 · Alexander Kusenko🇺🇸 · Misao Sasaki🇯🇵

    Dark matter fermions interacting via attractive fifth forces mediated by a light mediator can form dark matter halos in the very early universe. We show that bound systems composed of these halos are capable of generating gravitational wave (GW) signals detectable today, even when the individual halos are very light. The Yukawa force dominates the dynamics of these halo binaries, rather than gravity. As a result, large GW signals can be produced at initially extremely high frequencies, which are then redshifted to frequency bands accessible to current or future GW observatories. In addition, the resulting GW signals carry distinctive features that enable future observations to distinguish them from conventional ones. Notably, even if only a tiny fraction of dark matter experiences strong fifth-force interactions, such effects provide a new avenue to discover self-interacting dark matter through GW observations.

    ↳ astro-ph.COgr-qchep-ph4 citations
25. 25*

    Phenomenology of light baryon resonances

    Michael Döring🇺🇸

    Protons and neutrons are the building blocks of matter, glued together in nuclei by strong interactions. They can be excited by pions, real and virtual photons, neutrinos and other probes. These excitations are referred to as light baryon resonances. A short, pedagogical overview of the field is presented including experimental progress, interpretation of light baryon resonances, and a focus on analysis methods to extract the resonance spectrum from data.

    ↳ nucl-thhep-phnucl-ex3 citations
26. 26*

    Search potential for ${\tilde{b}}_1\to tW{\tilde{\chi }}_1^0$ via ${\tilde{\chi }}_1^{\pm }$ at the LHC and HL-LHC, with multi-lepton signatures

    Alexandra Tudorache🇷🇴 · Otilia Ducu🇷🇴

    The search potential for sbottom pair production in an R-parity conserving scenario is explored in multi-lepton final states at LHC Run-3 and the HL-LHC. In this model, the sbottom decays via a chargino, ${\tilde{b}}_1\to t{\tilde{\chi }}_1^{\pm }$, with a branching ratio (BR) of 100%. The chargino subsequently decays into a $W$ boson and the lightest neutralino, ${\tilde{\chi }}_1^{\pm }\to W{\tilde{\chi }}_1^0$, also with a BR of 100%. Two mass configurations are considered for ${\tilde{\chi }}_1^0$: a fixed value of 50 GeV, and a scenario where ${\tilde{\chi }}_1^{\pm }$ is 100 GeV heavier than ${\tilde{\chi }}_1^0$. The study follows the ATLAS object definitions and event selection criteria as detailed in Refs.1-3, extending the analysis presented in Ref. 2. Results are presented as projected exclusion limits in the ${\tilde{b}}_1$-${\tilde{\chi }}_1^0$ and ${\tilde{b}}_1$-${\tilde{\chi }}_1^{\pm }$ mass planes for three center-of-mass energies (13 TeV, 13.6 TeV, and 14 TeV) and three integrated luminosity scenarios (139 fb${}^{-1}$, 300 fb${}^{-1}$, and 3000 fb${}^{-1}$). Depending on the ${\tilde{\chi }}_1^0$ mass assumption, sbottom masses up to 1.28 TeV can be excluded at the HL-LHC with 3000 fb${}^{-1}$. These projections highlight the impact of alternative mass configurations on the sensitivity of multi-lepton \sbsbModel searches and provide guidance for future strategies targeting challenging SUSY scenarios at the LHC.

    ↳ hep-exhep-phInt.J.Mod.Phys.A(2025)·0 citations
27. 27*

    The Formation Rate and Luminosity Function of Fast X-ray transients from Einstein probe

    Yizhou Guo🇨🇳 · Houdun Zeng🇨🇳 · Junjie Wei🇨🇳 · Hao Zhou🇨🇳 · Zhiping Jin🇨🇳 · Xuefeng Wu🇨🇳 · Daming Wei🇨🇳

    Following its launch on 2024 January 9, the Einstein Probe (EP) telescope has detected hundreds of fast X-ray transients (FXTs), yet their physical origins remain elusive. Understanding their luminosity function and formation rate is crucial for elucidating their nature. Recently, the EP team has provided the latest catalog of EP-detected FXTs. Based on this catalog, we present a model-independent nonparametric approach to derive the luminosity function and formation rate of FXTs. Our analysis reveals significant cosmological luminosity evolution, characterized by a scaling relationship of $(1+z{)}^{3.58}$. After accounting for this evolution, we establish that the local luminosity function is best represented by a broken power law, with a break luminosity of $(4.17\pm 0.34)\times 10^{46}$ erg/s. The formation rate exhibits a broken power law as $\rho (z)\propto (1+z{)}^{-4.25}$ at $z⪅0.9$ and $\rho (z)\propto (1+z{)}^{-0.26}$ at $z⪆0.9$, yielding a local rate of approximately $153.8_{-95.1}^{+249.4}$ Gpc${}^{-3}$ yr${}^{-1}$. This rate is higher than that of long gamma-ray bursts (LGRBs). Our findings indicate that a component of FXTs is associated with LGRBs.

    ↳ astro-ph.HEhep-phApJL(2025)·5 citations
28. 28*

    Hyperons and $\Delta$'s in rotating protoneutron stars: Local properties

    Franciele M. da Silva🇧🇷 · Adamu Issifu🇧🇷 · Luis C. N. Santos🇧🇷 · Tobias Frederico🇧🇷 · Débora P. Menezes🇧🇷

    The structural evolution of rotating protoneutron stars encodes essential information about their observable signatures, while microscopic properties provide complementary knowledge to advance observational investigations. Using a relativistic mean-field model with density-dependent couplings that account for temperature and particle composition, we investigate rotation, neutrino-emission-driven changes in angular momentum, particle distributions, temperature profiles, and sound speed to probe the internal dynamics of protoneutron star matter. Additionally, we track the evolution of macroscopic quantities such as energy distribution and gravitational mass and establish direct links between microphysics and global evolution. Extending the framework of Phys. Rev. D 112, 023007 (2025), which focuses on the global properties of rotating protoneutron star evolution, our results reveal that protoneutron star deformation and thermal evolution are governed by angular momentum, mass, and composition. Exotic matter (hyperons and $\Delta$-resonances) and rapid rotation enhance deformation leading to a reduction in core temperature, whereas slowly rotating stars like PSR J0740$+$6620 remain nearly spherical. Our predicted equatorial radii for PSR J0740$+$6620, $13.0\mathrm{km}<R_e<13.5\mathrm{km}$, are consistent with NICER measurements. These findings constrain the EoS, requiring a self-consistent treatment of rotation, mass-dependent compression, and composition-driven modeling to accurately model protoneutron star evolution in the context of multi-messenger astrophysics.

    ↳ astro-ph.HEastro-ph.SRhep-phPRD(2026)·1 citation
29. 29*

    Mass and spin coevolution of black holes inspiralling through dark matter

    Theophanes K. Karydas🇳🇱 · Rodrigo Vicente🇳🇱 · Gianfranco Bertone🇳🇱

    In extreme/intermediate-mass-ratio inspirals (E/IMRIs) embedded in dark-matter (DM) spikes, the secondary black hole can accrete collisionless particles from the surrounding halo. We study how the companion's spin controls this process, and the ensuing back-reaction on the magnitude and direction of the companion's spin vector. We find that higher spin suppresses the mass accretion rate but enhances the accretion-induced torques, driving spin-down and secular alignment of the companion's spin with the orbital plane. Collisionless DM accretion generically imprints a near-universal mass-spin correlation characterized by a spin-evolution parameter $s\simeq 2.8$, much larger than is the case for typical astrophysical environments, and largely independent of the local DM density and the spike slope. The associated spin-down proceeds on astrophysically relevant timescales, thus observations of rapidly spinning IMRI companions would disfavor the presence of dense DM environments, providing constraints complementary to those arising from dynamical friction.

    ↳ gr-qcastro-ph.COastro-ph.GAastro-ph.HE+1PRD(2026)·7 citations
30. 30*

    Resonant Loop Interferometers for High-Frequency Gravitational Waves

    Jan Heisig🇩🇪

    Gravitational waves at kilohertz and higher frequencies offer a unique probe of the early Universe at temperatures well beyond the reach of the cosmic microwave background, corresponding to energy scales $\gtrsim 10^9$GeV. Existing detector concepts fall many orders of magnitude short of the big-bang nucleosynthesis (BBN) bound on the stochastic background in this regime. We propose a new interferometric architecture based on closed optical loops, in which the gravitational-wave-induced phase shift accumulates coherently over many traversals. This produces sharp, narrowband resonances whose predictable comb structure provides a distinct experimental signature. For a folded loop with parameters compatible with the Einstein Telescope infrastructure, and finesse values of order 500, we project sensitivity that approaches and even surpasses the BBN bound up to tens of kilohertz after one year of integration. Such loop interferometers thus open a realistic and distinctive path toward exploring high-frequency stochastic gravitational-wave backgrounds.

    ↳ gr-qcastro-ph.COastro-ph.IMhep-phClass.Quant.Grav.(2026)·3 citations
31. 31*

    Shock Wave in the Beirut Explosion: Theory and Video Analysis

    Adam J. Czarnecki · Andrzej Czarnecki🇨🇦 · Raquel Secrist · Julia Willsey

    Videos of the 2020 Beirut explosion offer a rare opportunity to see a shock wave. We summarize the non-linear theory of a weak shock, derive the Landau-Whitham formula for the thickness of the overpressure layer and, using frame-by-frame video analysis, we demonstrate agreement of data and theory.

    ↳ nlin.CDhep-phphysics.geo-ph0 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.