Tue·Nov 4, 2025Tuesday·November 4, 2025

1. 01*

   Nucleosynthesis and CMB bounds on photophilic ALPs: a fresh look

   Miguel Escudero🇨🇭 · Clara Garcia-Perez🇨🇭 · Maksym Ovchynnikov🇨🇭

   We provide a fresh look at the cosmological constraints on axion-like particles (ALPs) that couple predominantly to photons, focusing on lifetimes ${\tau }_a\lesssim 10^4\mathrm{s}$ and masses $m_a\lesssim 10\mathrm{GeV}$. We consider Big Bang Nucleosynthesis (BBN) and Cosmic Microwave Background (CMB) bounds and explore how these limits depend upon the unknown reheating temperature of the Universe, $T_{\mathrm{reh}}$. Compared with some previous studies, we account for the rare decays of these ALPs into light hadrons and show that this leads to extended constraints for several reheating temperatures. Our limits are cast in a model-independent way, and we identify regions of parameter space where these ALPs could alleviate small tensions in the determinations of $N_{\mathrm{eff}}$ and the deuterium abundance.

   hep-phastro-ph.COEPJC(2026)·11 citations
2. 02*

   One Loop Calculations of Rare B-decays Beyond the Standard Model

   Maryam Bibi

   Rare $B$-meson decays, suppressed in the Standard Model (SM) by the GIM mechanism, are sensitive probes of new physics. In particular, loop-level $b\to s$ transitions can reveal effects of heavy virtual particles such as vector-like quarks (VLQs). VLQs, which do not require electroweak symmetry breaking for mass generation, can mix with SM quarks and induce flavor-changing neutral currents (FCNCs). We investigate the impact of down-type iso-singlet VLQs on the rare decay $B^{+}\to K^{+}\nu \bar{\nu }$, a theoretically clean channel sensitive to new physics. The Belle-II collaboration recently reported a branching ratio of $[2.3\pm 0.5]\times 10^{-5}$, significantly higher than the SM prediction of $[0.45\pm 0.07]\times 10^{-5}$, suggesting possible new contributions. To constrain the relevant mixing parameter $U_{sb}$, we also analyze related decays such as $B_s\to {\mu }^{+}{\mu }^{-}$ and $B\to X_s{\mu }^{+}{\mu }^{-}$. Incorporating VLQ effects into the effective field theory framework, we compute modified Wilson coefficients ($C_7$, $C_9$, $C_{10}$, $C_L$) and predict enhanced branching ratios for $B\to X_s\nu \bar{\nu }$ and $B\to K\nu \bar{\nu }$. ${\chi }^2$ contour analyses indicate that VLQs can account for observed anomalies, providing a viable and testable extension to the SM.

   hep-ph0 citations
3. 03*

   Optimization of factorization scale in QED Drell-Yan-like processes

   Andrej Arbuzov🇷🇺 · Uliana Voznaya🇷🇺 · Aliaksandr Sadouski🇧🇾

   The dependence of corrections due to the initial state radiation in $e^{+}{e}^{-}$-annihilation processes on the choice of the factorization scale is investigated. Different prescriptions of the factorization scale choice are analyzed within the leading and next-to-leading logarithmic approximations. Comparisons with the known complete two-loop results are used to optimize the scale choice.

   hep-ph1 citation
4. 04*

   Non-perturbaitve effects for the isoscalar light vector $\omega$-meson in charmed meson semileptonic decays

   Yin-Long Yang🇨🇳 · Fang-Ping Peng🇨🇳 · Yan-Ting Yang🇨🇳 · Hai-Bing Fu🇨🇳 · Sheng-Quan Wang🇨🇳

   Motivated by the renewed attention from the recent BESIII experiment on the semileptonic decay $D\to V\ell {\nu }_{\ell }$, we investigate semileptonic decay $D^{+}\to \omega {\ell }^{+}{\nu }_{\ell }$ within the framework of QCD light-cone sum rule in this work. By constructing correlation function with right-handed chiral current, the transverse twist-2 light-cone distribution amplitudes (LCDA) ${\varphi }_{2;\omega }^{\perp }(x,\mu )$ dominates the contribution in TFFs. We study the properties of twist-2 LCDA ${\varphi }_{2;\omega }^{\perp }(x,\mu )$ through light-cone harmonic oscillator model. Applying it to the TFFs, we obtained $A_1(0)$, $A_2(0)$, $V(0)$, and $A_0(0)$ at large recoil point. Two TFF ratios are $r_V=1.40_{-0.19}^{+0.21}$ and $r_2=1.01_{-0.16}^{+0.17}$. After extrapolating those TFFs to the whole physical $q^2$ region by using the simplified $z(q^2,t)$ series expansion, the ratio of longitudinal and transverse decay widths is ${\Gamma }_{\mathrm{L}}/{\Gamma }_{\mathrm{T}}=0.987_{-0.121}^{+0.107}$. Then, we get branching fraction $\mathcal{B}(D^{+}\to \omega e^{+}{\nu }_e)=(1.848_{-0.330}^{+0.365})\times 10^{-3}$ and $\mathcal{B}(D^{+}\to \omega {\mu }^{+}{\nu }_{\mu })=(1.782_{-0.303}^{+0.334})\times 10^{-3}$, which is in good agreement with BESIII and CLEO Collaborations. Taking into account the secondary decay $\omega \to {\pi }^{+}{\pi }^{-}{\pi }^0$, we predict branching fraction of five body decay as $\mathcal{B}(D^{+}\to \omega (\to {\pi }^{+}{\pi }^{-}{\pi }^0)e^{+}{\nu }_e)=(1.648_{-0.305}^{+0.341})\times 10^{-3}$ and $\mathcal{B}(D^{+}\to \omega (\to {\pi }^{+}{\pi }^{-}{\pi }^0){\mu }^{+}{\nu }_{\mu })=(1.589_{-0.281}^{+0.313})\times 10^{-3}$. Finally, we predict the forward-backward asymmetry $A_{\mathrm{FB}}^{\ell }$, lepton-side convexity parameter $C_{\mathrm{F}}^{\ell }$, longitudinal (transverse) polarization $P_{\mathrm{L}(\mathrm{T})}^{\ell }$, as well as longitudinal polarization fraction $F_{\mathrm{L}}^{\ell }$.

   hep-phEPJC(2026)·0 citations
5. 05*

   Impact of Localization in Early-Universe QCD Phase Transition

   Janus Capellan Aban🇹🇼 · Edmayelle Villavicencio Alforja · Vincent Gene L. Otero

   We introduce a phenomenological modification of the MIT bag model equation of state that incorporates quark localization arising from gluon-induced disorder in the quark-gluon plasma. This model effectively reduces the quark degrees of freedom encoded in the product of the disorder activation function $G(W)$ and the localization efficiency factor $H(T)$. As a result, the critical temperature is increased roughly by 7%. Employing the Friedmann equation, we find that the onset of the phase transition occurs earlier. Consequently, the mixed phase duration is only $8.22\mu s$, which is 24% shorter than the bag model, and the hadronic phase cools faster. The Stephan-Boltzmann constant is reached at much higher temperatures, causing the energy density and pressure curves of the bag model to shift downward and yielding better agreement with the lattice QCD data from the HotQCD collaboration. Our results show that the localization of quarks plays a significant role in the cooling dynamics of the early universe.

   hep-ph0 citations
6. 06*

   Empirical Reconstruction of the JSNS${}^2$ KDAR ${\nu }_{\mu }$-${}^{12}$C Missing-Energy Spectrum with a Two-Ex-Gaussian and Generalized-Tail Model

   Kyung Kwang Joo🇰🇷 · Jubin Park🇰🇷 · Minkyu Lee🇰🇷 · Myung-Ki Cheoun🇰🇷

   Recent analyses of the JSNS${}^2$ monoenergetic ${\nu }_{\mu }$ scattering on ${}^{12}$C at 235.5~MeV have compared the measured missing-energy spectrum with several nuclear models, including \textsc{NuWro}, \textsc{GiBUU}, and RMF+Achilles. While these models reproduce the overall peak position, their respective ${\chi }^2$ values of $35.5$, $176.8$, and $58.1$ indicate that none can simultaneously describe the spectral width and the high-energy tail, reflecting limitations in the treatment of binding energy, two-particle--two-hole (2p-2h) excitations, and final-state interactions (FSI). To address these discrepancies, we introduce an empirical yet physically motivated representation of the spectrum based on two exponentially modified Gaussian (ex-Gaussian) components for p- and s-shell knockout and a generalized power-exponential continuum term describing multinucleon and FSI-induced strength. The fit reproduces the JSNS${}^2$ data within the fitted energy range with ${\chi }^2=8.0$ for 6 degrees of freedom. yielding parameters that quantify asymmetric broadening of the s-shell while preserving a narrow quasielastic p-shell response. This compact model demonstrates that a minimal empirical framework can capture key features of the nuclear response and provides a useful reference for phenomenological comparisons and future studies of quasielastic and 2p-2h dynamics in the few-hundred-MeV regime.

   hep-phnucl-th0 citations
7. 07*

   Implications of portal vector-like lepton on associated Higgs production at a multi-TeV muon collider

   Krishna Tewary🇮🇳 · Sanjoy Biswas🇮🇳 · Shivam Verma🇮🇳

   We have explore a portal vector-like lepton (pVLL) extension of the Standard Model (SM) and study its implications for Higgs and vector-boson associated production ($hV$, with $V=Z$-boson or dark photon) at a future muon collider facility. We show that while the ${\mu }^{+}{\mu }^{-}\to hZ$ production rate remains close to its SM prediction in a wide range of parameter space, the rate for ${\mu }^{+}{\mu }^{-}\to h{\gamma }_d$ can be substantially enhanced owing to the non-decoupling nature of the interaction involving the heavy lepton, the muon and the dark photon. We demonstrate that the $h{\gamma }_d$ production rate can exceed the corresponding $hZ$ rate by a factor of $1$-$100$ within the perturbative unitarity limit, making it a promising channel for probing Higgs interactions and potential new physics effects. We also examine the role of the pVLL state in the context of dark matter (DM) phenomenology and identify regions of parameter space consistent with the observed relic abundance by extending the simplified setup with a viable DM candidate. The $h{\gamma }_d$ production can also be used to constrain the dark photon mass ($m_{{\gamma }_d}$) and/or the dark gauge coupling ($g_d$) consistent with various constraints including the current muon $g-2$ measurements within the pVLL framework. We perform a detailed collider analysis of the $h{\gamma }_d$ process in the $b\bar{b}+$ missing energy final state. A $2\sigma$ exclusion limit for $m_{{\gamma }_d}$ up to $80$ GeV is obtained assuming $g_d=0.05$, $\sin {\theta }_L=4\times 10^{-5}$, $\sin {\theta }_s=0.05$, for a heavy lepton mass $\sim 3$ TeV at a $3$ TeV muon collider with an integrated luminosity of $1$ ab${}^{-1}$.

   hep-phhep-exPRD(2026)·4 citations
8. 08*

   Tau neutrino as a probe of charged non-standard interactions at DUNE

   A. Cherchiglia🇧🇷 · O. L. G. Peres🇧🇷 · E. S. Souza🇧🇷

   In this work, we study the influence of charged-current non-standard interactions (CC-NSI) at a DUNE-like experiment. We are particularly interested in the tau neutrino channel accessible at DUNE, given the higher energy neutrino flux expected to be achieved by the experiment. We focus on CC-NSI that may affect the pion decay, the primary source of neutrinos for DUNE. We show that the expected sensitivity at the near detector may supersede the present bounds coming directly from pion decay by one order of magnitude.

   hep-phPRD(2026)·2 citations
9. 09*

   Constraints on active-sterile neutrino transition magnetic moments from low-energy electronic recoils at direct detection experiments

   M. F. Mustamin🇹🇷 · M. Demirci🇹🇷

   Sterile neutrinos can potentially be produced through neutrino transition magnetic moments in neutrino-electron scattering. In this work, we investigate this dipole portal by analyzing low-energy electronic recoil data from the PandaX-4T (Run0 and Run1) and XENONnT experiments. We focus on the up-scattering of solar neutrinos into sterile states via the transition magnetic moment. By performing a comprehensive analysis, we derive robust exclusion limits on the neutrino flavor-independent and flavor-dependent transition magnetic moments for fixed sterile neutrino masses as well as on the mass-coupling parameter space. We demonstrate that, since they can detect solar neutrino-induced processes, direct detection experiments offer a unique framework for studying all possible neutrino flavors. The obtained limits extend the sensitivity to previously unexplored regions of the parameter space.

   hep-phPLB(2026)·1 citation
10. 10*

    In-medium mass shifts of $B_c^{(\ast )},B_s^{(\ast )}$ and $D_s^{(\ast )}$ mesons

    K. Tsushima🇧🇷 · S.L.P.G. Beres🇧🇷 · G.N. Zeminiani🇧🇷

    We present our predictions for the Lorentz scalar mass shifts of two-flavored heavy mesons, $B_c^{(\ast )},B_s^{(\ast )}$ and $D_s^{(\ast )}$ in symmetric nuclear matter. The in-medium mass shifts are estimated by evaluating the lowest order one-loop self-energies of the mesons based on a flavor-SU(5) effective Lagrangian approach. In-medium properties necessary for the estimates are calculated by the quark-meson coupling (QMC) model. The enhanced self-energies of the mesons in symmetric nuclear matter relative to those in free space, yield the negative mass shifts of these mesons.

    hep-phhep-exhep-latnucl-ex+1EPJ Web Conf.(2026)·0 citations
11. 11*

    Probing Short-Distance Modifications of Gravity via Spin-Independent and Spin-Dependent Effects in Muonic Atoms

    J. E. J. Matias🇧🇷 · A. S. Lemos🇧🇷 · F. Dahia🇧🇷

    High-precision spectroscopy of muonic atoms provides a powerful probe for new short-range interactions predicted by theories beyond the Standard Model (SM). In this work, we derive new constraints on both spin-independent and spin-dependent non-Newtonian gravity by leveraging the outstanding sensitivity of these systems. For spin-independent Yukawa-type forces, we analyze two complementary approaches: the $2S-2P$ Lamb shift in the muonic helium-4 ion and the deuteron-proton squared charge radii difference obtained from the muonic hydrogen-deuterium isotope shift. The found constraints have reached a competitive level at sub-picometer scales, with the isotope shift method yielding the most stringent bounds for interaction ranges $\lambda \lesssim 10^{-13}\text{m}$. For spin-dependent effects, we analyze the influence of the gravitational spin-orbit coupling on the $2P_{3/2}-2P_{1/2}$ fine-structure splitting in muonic helium, establishing new limits on Post-Newtonian parameters. These bounds are shown to be more restrictive than those from other leading experimental techniques for ranges $\lambda \lesssim 10^{-10}\text{m}$. Our findings highlight the widespread usefulness of muonic atoms in exploring new fundamental physics at short-distance scales.

    hep-phgr-qchep-thphysics.atom-phEur.Phys.J.Plus(2026)·3 citations
12. 12*

    Predictions for charged-hadron production in $p$-O collisions at LHC energies

    Luca Konrad🇩🇪 · Philipp Schulz🇩🇪 · Georg Wolschin🇩🇪

    We present predictions for centrality-dependent charged-hadron production in p-O collisions at top LHC energies based on a nonequilibrium-statistical relativistic diffusion model. Colour-glass condensate initial conditions are used in a three-sources momentum-space model for gluon-gluon, quark-gluon and gluon-quark sources. Our results are to be compared with forthcoming Run3 pseudorapidity distributions for sqrt(s_NN)=9.618 TeV p-O collisions.

    hep-phPLB(2025)·2 citations
13. 13*

    Measuring gravitational wave spectrum from electroweak phase transition and Higgs self-couplings

    Shuo Guan🇨🇳 · Huai-Ke Guo🇨🇳 · Dian Jiao🇨🇳 · Qingyuan Liang🇨🇳 · Lei Wu🇨🇳 · Yang Zhang🇨🇳

    In this work, we demonstrate the complete process of using space-based gravitational wave detectors to measure properties of the stochastic gravitational wave background arising from a first-order electroweak phase transition. Based on frequency-domain simulations of the Taiji mission, including instrumental noise and astrophysical foregrounds, we perform parameter inference using both the Fisher information matrix and Bayesian Markov Chain Monte Carlo sampling. We show how the reconstructed spectrum constrains the macroscopic parameters of the phase transition, and further how these constraints map onto the underlying particle-physics parameters in a singlet-extended Standard Model. Our results demonstrate that the Higgs cubic and quartic self-couplings can be significantly constrained using gravitational wave observations, despite limitations arising from parameter degeneracy.

    hep-phPRD(2026)·10 citations
14. 14*

    Dimuon production in DIS with charm-mass effects

    Ilkka Helenius🇫🇮 · Hannu Paukkunen🇫🇮 · Sami Yrjänheikki🇫🇮

    Dimuon production in neutrino-nucleus collisions, an important constraint of strangeness in global parton distribution function analyses, is typically calculated by assuming it to be proportional to inclusive charm production. This approach breaks down beyond fixed-flavor leading-order calculations. In our previous work, we introduced an alternative approach based on semi-inclusive charmed-hadron production to compute dimuon production directly. We now present an extension to this work, where we compute the semi-inclusive hadron production in the SACOT-$\chi$ general-mass variable-flavor number scheme to take all charm-mass effects consistently into account. The results are in line with our expectations, with the dynamical charm-mass effects modifying our previous approximative calculation by up to $20\%$ at small values of $Q^2$.

    hep-phPoS(2025)·0 citations
15. 15*

    Precision Imaging of the Pion Emission Source in Heavy-Ion Collisions via a Global Rest Frame Analysis

    Qi-Chun Feng🇨🇳 · Yi-Bo Hao🇨🇳 · Yue-Kai Zhou🇨🇳 · Xu Sun🇨🇳 · Yue Jiang🇨🇳 · Jing-Bo Zhang🇨🇳 · Lei Huo🇨🇳 · Yan-Yu Ren🇨🇳

    Conventional imaging of pion emission sources, conducted in the center-of-mass frame of individual pion pairs (CMFP), suffers from frame-dependent kinematic distortions that bias the reconstructed source morphology. This method introduces spurious correlations due to the relative boost between the CMFP and the true source rest frame (CMFS), leading to systematic image distortions with a pronounced non-Gaussian tail. We present a transformative approach by performing correlation analysis directly in the global source rest frame (CMFS), the physically meaningful reference frame of the collision fireball. This paradigm shift eliminates kinematic contamination inherent in conventional CMFP-based imaging. The resulting source image shows a dramatic suppression of the non-Gaussian artifact and achieves significantly better agreement with pristine model source functions. Our technique offers a more direct and uncontaminated probe of the intrinsic source geometry, overcoming the limitations of prior methods. It provides a clearer and more accurate determination of the spacetime properties of the nuclear collision fireball, marking a significant advancement in the field.

    hep-ph0 citations
16. 16*

    U-spin symmetry energy and hyperon puzzle

    Hao-Song You🇨🇳 · Ting-Lan Yu🇨🇳 · Sophia Han🇨🇳 · Cheng-Jun Xia🇨🇳 · Ren-Xin Xu🇨🇳

    By combining the ($u$,$d$) I-spin doublets or ($d$,$s$) U-spin doublets, the SU(3) flavor symmetry of light quarks can be decomposed into SU(2)${}_I\times$U(1)${}_Y$ or SU(2)${}_U\times$U(1)${}_Q$ subgroups, which have been widely adopted to categorize hadrons and their decay properties. The I-spin counterpart for the interactions among nucleons has been extensively investigated, i.e., the nuclear symmetry energy $E_{\mathrm{sym}}(n_{\mathrm{b}})$, which characterizes the variation of binding energy as the neutron to proton ratio in a nuclear system. In this work, we propose U-spin symmetry energy $E_{\mathrm{U}}(n_{\mathrm{b}})$ for hyperonic matter to characterize the variation of binding energy with the inclusion of hyperons. In particular, being the lightest hyperon, $\Lambda$ hyperons are included in dense matter, where the U-spin symmetry energy $E_{\mathrm{U}}(n_{\mathrm{b}})$ is fixed according to state-of-the-art constraints from nuclear physics and astrophysical observations using Bayesian inference approach. It is found that $E_{\mathrm{U}}(n_{\mathrm{b}})$ is much smaller than that of $E_{\mathrm{sym}}(n_{\mathrm{b}})$, indicating much stronger proton-neutron attraction than that of nucleon-hyperon pairs. Consequently, the $\Lambda$ hyperon potential increases significantly with density and becomes repulsive at high densities. The results indicate that there is more than 50\% probability for the emergence of $\Lambda$ hyperons in posterior EOSs, which are likely to vanish at densities $n_{\mathrm{b}}\gtrsim 5n_0$. In scenarios where $\Lambda$ hyperons do emerge, the onset density $n_{\mathrm{b}}^{\Lambda }$ is typically within the range of $2n_0$--$5n_0$, corresponding to neutron stars more massive than $1.0{\mathrm{M}}_{\odot }$.

    hep-phastro-ph.HE0 citations
17. 17*

    Bayesian constraint of the initial condition for the Balitsky-Kovchegov equation at NLO

    Carlisle Casuga🇫🇮 · Henri Hänninen🇫🇮 · Heikki Mäntysaari🇫🇮

    We use Bayesian inference to constrain the parameters describing the initial amplitude input to the Balitsky-Kovchegov evolution equation at next-to-leading order accuracy against precise HERA total inclusive cross section and heavy quark data. The datasets are found to provide stringent constraints and, with consistent NLO treatment, a successful description of the data is obtained. The posterior distributions define the theoretical uncertainites that surround the non-perturbative initial condition and, thus, provide a way to propagate said uncertainties to CGC calculations at NLO.

    hep-phPoS(2025)·0 citations
18. 18*

    Stochastic gravitational wave from graviton bremsstrahlung in inflaton decay into massive spin 3/2 particles

    Diganta Das🇮🇳 · Mihika Sanghi🇮🇳 · Sourav🇮🇳

    The detection of primordial gravitational waves would offer a direct evidence of inflation and valuable insights into the dynamics of the early universe. During post-inflation reheating period, when the inflaton coherently oscillates at the bottom of its potential, primordial stochastic gravitational waves may be sourced by its perturbative decay into particles of different spins. Assuming the behavior of the potential near the minimum as a polynomial $V(\varphi )\sim {\varphi }^k$, where $k\ge 2$, and treating the inflaton as coherently oscillating classical field, we calculate the decay of inflaton into a pair of spin $3/2$ particles accompanied by graviton emission. We numerically study the reheating dynamics and calculate the stochastic gravitational wave spectra. Our analysis shows that the gravitational wave spectra can offer insights into the microscopic physics during inflation.

    hep-phastro-ph.COgr-qcPRD(2026)·5 citations
19. 19*

    Direct detection of solar chameleons with electron recoil data from XENONnT

    Guan-Wen Yuan🇮🇹 · Anne-Christine Davis🇬🇧 · Maurizio Giannotti🇪🇸 · Sunny Vagnozzi🇮🇹 · Luca Visinelli🇮🇹 · Julia K. Vogel🇩🇪

    We reassess prospects for direct detection of solar chameleons, in light of recent progress in modeling their production, and the availability of new XENONnT data. We show that the contribution from Primakoff production in the electric fields of electrons and ions dominates the electron recoil event rate, which is enhanced compared to earlier estimates based on magnetic conversion in the tachocline alone. We argue that the signal is governed by the effective coupling ${\beta }_{\text{eff}}\equiv {\beta }_{\gamma }{M}_e^{-4}$, which encodes the combined effects of production and detection, where ${\beta }_{\gamma }$ and $M_e$ are the chameleon-photon (conformal) coupling and chameleon-electron disformal coupling scale, respectively. Setting the height of the chameleon potential to the dark energy (DE) scale $\Lambda \simeq 2.4\text{meV}$, we show that XENONnT electron recoil data set the upper limit ${\log }_{10}{\beta }_{\text{eff}}<-6.9$. This limit is independent of the conformal matter coupling ${\beta }_m$ and index $n$, and applies to the whole class of inverse power-law chameleons, well beyond the $n=1$ case usually studied. We comment on how future multi-target experiments and lower-threshold analyses could distinguish solar chameleons from other light (pseudo)scalar particles such as axions. Our work demonstrates that existing dark matter direct detection experiments can probe regions of parameter space relevant to screened DE models, providing complementary tests to astrophysical and fifth-force searches at no additional experimental cost.

    hep-phastro-ph.COgr-qchep-exPRD(2026)·8 citations
20. 20*

    Light scalars in light of UV/IR mixing: classicalization via synergy between Vainshtein and chameleon screenings

    Florian Nortier🇫🇷

    Effective field theories featuring light scalar fields play a pivotal role in addressing fundamental questions in (astro)particle physics and cosmology. However, such theories often confront hierarchy problems in the absence of a symmetry. Self-completion via classicalization offers a non-Wilsonian approach to ultraviolet (UV) completion, wherein new scalar self-interactions involving derivatives give rise to Vainshtein-like screening around energy-momentum sources. Rather than introducing new UV degrees of freedom to restore unitarity at high energies, these theories reshuffle their infrared (IR) degrees of freedom by generating extended semi-classical objects -- referred to as classicalons -- which decay into a multitude of soft particles. This mechanism incorporates non-localizable fields, thereby realizing a form of UV/IR mixing that is analogous to the dynamics of black holes in gravitational theories. In this article, having reviewed the fundamental principles of classicalization with a simple k-essence model, we then argue the necessity of maintaining a little hierarchy between the scalar mass and the scale of the first new resonances, thereby illustrating the impact of UV/IR mixing on hierarchy problems. Additionally, we investigate the effects of a scalar potential and couplings to fermions on the Vainshtein screening mechanism. We discuss that a chameleon-like screening mechanism must accompany the Vainshtein screening to preserve the integrity of classicalon solutions.

    hep-phastro-ph.COgr-qchep-thJHEP(2026)·2 citations
21. 21*

    Form of axion in DFSZ models with $U(1{)}_{PQ}$ symmetry

    V. H. Binh🇷🇺 · H. N. Long

    Form of axion state in the DFSZ model is determined by exacted diagonalizing of the mass mixing matrix of $CP$-odd sector. After applying $PQ$ mechanism to determine $PQ$ charges of particles of the model, these $PQ$ charges are used to define the general form of axion. Both of these two methods give consistent and reasonable physical state of axion. The constraint of $PQ$ charge in $DFSZ-I$ model is also pointed out. Then, anomalous couplings of axion-photon-photon is re-examined. Triple-couplings of axion with two fermions are studied. The decay of and axion into a pair of photon is also considered via re-normalizable interactions arising from kinetic terms of scalar fields.

    hep-phTheor.Math.Phys.(2026)·1 citation
22. 22*

    The double copy effective action: a quantum (chromodynamics) approach to space-time

    John Joseph M. Carrasco🇺🇸 · Suna Zekioglu🇺🇸

    Conventional Lagrangian formulations of gauge and gravity theories emphasize compactness and off-shell symmetry. This often obscures the structure of on-shell physical observables. In this work, we present a constructive framework that elevates gauge-invariant scattering amplitudes to the defining data for quantum field theory actions, including effective field theories. Focusing on double-copy theories, we promote color-dual amplitude numerators to quantum operators. This enables the systematic identification of novel local operator content at each multiplicity and the construction of double-copy-compatible actions. By applying this framework to the well-established double-copy relationship between Einstein gravity and Yang-Mills theory, which holds for all-multiplicity tree-level amplitudes, we demonstrate a systematic path to constructing the operator expansion of $\sqrt{-g}R$ from factorized gauge-theory components. This clarifies how gravitational interactions can be understood as emerging from simpler gauge-theoretic structures at the action level. This formalism extends color-kinematics duality from amplitude data to operator constructions, naturally realizing the double copy at the level of actions and asymptotic quantum states. We illustrate the method with Yang-Mills theory, Einstein gravity, and its application to generating higher-derivative operators inspired by Z-theory and open superstring amplitudes. This work provides a concrete bridge between structured amplitudes and effective actions, offering a physically grounded alternative to traditional EFT basis-building. It reveals at the operator level deep structural connections between gauge theory and gravity (connections long recognized in scattering amplitudes) from fundamental interactions to their quantum state descriptions and higher-derivative extensions.

    hep-phgr-qchep-thJHEP(2026)·5 citations
23. 23*

    Axionlike particle searches in short-baseline liquid scintillator neutrino detectors

    D. Aristizabal Sierra🇨🇱 · L. Duque🇲🇽 · O. Miranda🇲🇽 · H. Nunokawa🇧🇷

    Short-baseline reactor neutrino experiments using large organic liquid scintillator detectors provide an experimentally rich environment for precise neutrino physics. Neutrino detection is done through inverse beta decay and relies on prompt and delayed signals, which enable powerful background discrimination. In addition to their neutrino program, they offer an ideal experimental environment for other physics searches. Here we discuss the case of axionlike particles (ALPs) produced by either Primakoff-like or Compton-like processes. Their detection relies on the corresponding inverse processes, axio-electric absorption and ALP decays to photon or electron pairs. Assuming experimental parameter values broadly representative of JUNO-TAO or CLOUD we show that scattering ALP processes involve a prompt photon signal component followed by a delayed photon signal about 5 ns after. We point out that if these signals can be resolved, this might allow for efficient ALP signal discrimination against radioactive background. Likewise, coincident events from ALP decays and scintillation light followed by Auger electrons from axio-electric absorption might as well allow for background discrimination. We determine sensitivities in both the nuclear and electron channels using as a benchmark case an experimental setup resembling that of the CLOUD or JUNO-TAO detectors. Our findings demonstrate that with efficient background discrimination these type of technology has the capability to test regions in parameter space not yet explored. In particular, the cosmological triangle can be fully tested and regions of MeV ALP masses with ALP-electron couplings of the order of $10^{-8}$ can be entirely explored.

    hep-phhep-exJHEP(2026)·1 citation
24. 24*

    Avoiding Blindness in Baryon Number Violating Processes: Free-Beam and Intranuclear Paths to Neutron-Antineutron Transitions

    Joshua L. Barrow🇺🇸 · Peter Fierlinger🇩🇪 · Yuri Kamyshkov🇺🇸 · Bernhard Meirose🇸🇪 · David Milstead🇸🇪 · Rabindra N. Mohapatra🇺🇸 · Valentina Santoro🇸🇪

    Experimental searches for neutron--antineutron ($n\to \bar{n}$) transitions can be considered via two approaches: conversion in free-neutron beams and intranuclear transformation leading to matter instability in large-mass detectors. Plans for next-generation searches make it timely to highlight the complementarity, necessity, and limitations of each method. Converting the bound neutron limit into one for free neutrons traditionally utilizes nucleus-specific estimates of the in-medium suppression of $n\to \bar{n}$, obtained within mean-field theory under a single-operator assumption. This paper highlights how this suppression can be scenario-dependent, which can lead to deviations from the standard approach that can span several orders of magnitude. A further goal of the paper is to point out the need for a broader phenomenology program for $n\to \bar{n}$ that is akin to those developed for electric dipole moments and other systems for which short-distance new physics must be studied in-medium.

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

    Constraining memory-burdened primordial black holes with graviton-photon conversion and binary mergers

    Po-Yan Tseng🇹🇼 · Yu-Min Yeh🇹🇼

    The memory-burden effect stabilizes the evaporating Primordial Black Holes (PBHs) before its complete decay. This also suppresses the evaporation flux via the entropy factor to the $k$-th power and circumvents severely astrophysical and cosmological constraints, such that it opens a new mass window for PBH Dark Matter lighter than $10^{15}$ g which has entered the memory-burden phase in the present epoch. In this study, we propose two scenarios to probe PBHs in the earlier semiclassical phase that evaporate at unsuppressed rates. The first scenario considers gravitons, emitted semiclassically from PBHs, propagating across the recombination epoch, then the magnetic field in the cosmological filaments converts them into photons via the Gertsenshtein effect. The second scenario relies on the PBHs mergers today, reproducing young semiclassical black holes with unsuppressed evaporation, but it is highly model dependent and has no sufficient theory support. For phenomenology studies, we perform computations of the extragalactic photon spectrum from PBHs emission according to these scenarios. The upper limits on the fractional abundance of PBH are obtained by comparing with the sensitivities of gamma-ray observations. The graviton-photon conversion scenario excludes the mass window $7.5\times 10^5\mathrm{g}\le M_{\mathrm{PBH}}\le 4.4\times 10^7\mathrm{g}$ with $f_{\mathrm{PBH}}{|}_{T_{\varphi }}\ge 1$ and $k=1$, assuming the optimistic magnetic field $B_0=100$ nG. Meanwhile, the merging scenario, which is insensitive on $k$, restricts PBH Dark Matter lighter than $2.2\times 10^{11}$ g.

    hep-phEPJC(2026)·5 citations
26. 26*

    Incoherent Particle Production in Ultraperipheral Heavy Ion Collisions

    L. A. Harland-Lang🇬🇧

    In this paper, we present the first complete treatment of incoherent photon-initiated production in ultraperipheral heavy ion collisions, focussing on the dilepton and diphoton final states. In the former case we compare to the ATLAS measurement of dielectron production and find that our predictions match the data very well. In the latter case we show that this contribution is too small to explain the observed broad in diphoton acoplanarity background to the purely coherent light-by-light scattering signal. We in addition consider a new `quark emission' topology, which while naively might be expected to dominate the incoherent diphoton production channel, is in fact found to be kinematically suppressed. Finally, we revisit QCD-initiated diphoton production and issue of theoretical uncertainties in this case. We find that this again cannot explain the observed size of the higher acoplanarity background. The production mechanism leading to this background to light-by-light production, and the reason for its observed enhancement in comparison to the dilepton case, therefore remains unclear.

    hep-phhep-exnucl-exnucl-thPRD(2026)·0 citations
27. 27*

    SEAL - A Symmetry EncourAging Loss for High Energy Physics

    Pradyun Hebbar · Thandikire Madula🇬🇧 · Vinicius Mikuni🇺🇸 · Benjamin Nachman🇺🇸 · Nadav Outmezguine🇺🇸 · Inbar Savoray🇺🇸

    Physical symmetries provide a strong inductive bias for constructing functions to analyze data. In particular, this bias may improve robustness, data efficiency, and interpretability of machine learning models. However, building machine learning models that explicitly respect symmetries can be difficult due to the dedicated components required. Moreover, real-world experiments may not exactly respect fundamental symmetries at the level of finite granularities and energy thresholds. In this work, we explore an alternative approach to create symmetry-aware machine learning models. We introduce soft constraints that allow the model to decide the importance of added symmetries during the learning process instead of enforcing exact symmetries. We investigate two complementary approaches, one that penalizes the model based on specific transformations of the inputs and one inspired by group theory and infinitesimal transformations of the inputs. Using top quark jet tagging and Lorentz equivariance as examples, we observe that the addition of the soft constraints leads to more robust performance while requiring negligible changes to current state-of-the-art models.

    hep-phcs.LGhep-ex3 citations
28. 28*

    Dark neutron stars from a heavy dark sector

    Jacob A. Litterer🇵🇹 · João G. Rosa🇵🇹

    We study the formation and properties of dark neutron stars in a scenario where dark matter is made up of (heavy) dark baryons in a sequestered copy of the MSSM. This scenario naturally explains the coincidence of baryonic and dark matter abundances without the need for tuning particle masses. In particular, the supersymmetry breaking scales in the visible and dark sectors may differ by up to 10-11 orders of magnitude. We argue that dark neutrons should be the lightest dark baryons, but that dark protons may be cosmologically long lived. This allows a small fraction of dark matter to remain ionized until the first halos start to form, providing cooling mechanisms that foster the gravitational collapse and fragmentation of sub-halo structures, ultimately resulting in dark neutron star and black hole formation. For a wide range of model parameters, we find dark neutron stars with generally smaller mass and radius than ordinary visible sector neutron stars. We also discuss their potential detectability, particularly through gravitational microlensing and dark magnetic dipole radiation at radio frequencies through photon-dark photon kinetic mixing.

    hep-phastro-ph.COgr-qc1 citation
29. 29*

    An effective field theory for thermal QCD with 2+1 flavours

    Sourendu Gupta🇮🇳 · Pritam Sen🇮🇳 · Rishi Sharma🇮🇳

    We write a long-distance effective field theory (EFT) for QCD at finite temperature just below the crossover temperature $T_c$. The low energy constants (LECs) of this EFT are obtained from lattice measurements of the screening mass of pions at two temperatures for $N_f=2+1$ using lattice results obtained at physical values of pion and Kaon masses, and $N_f=2$ where the lattice simulations were performed with a heavier pion mass. The EFT gives good predictions for other static pion properties for $N_f=2$, where lattice results are available. We show the corresponding predictions for $N_f=2+1$, where they are not yet measured. We demonstrate that EFT gives excellent predictions for the phase diagram in $N_f=2+1$. The predictions for the pressure are investigated, and predictions are also given for a Wick-rotated real-time quantity called the kinetic mass.

    ↳ hep-lathep-phPRD(2026)·2 citations
30. 30*

    Single-Point Search for eV-scale Axion-like particles with Variable-Angle Three-Beam Stimulated Resonant Photon Collider

    Takumi Hasada🇯🇵 · Kensuke Homma🇯🇵 · Airi Kodama🇯🇵 · Haruhiko Nishizaki🇯🇵 · Yuri Kirita🇯🇵 · Shin-ichiro Masuno🇯🇵 · Shigeki Tokita🇯🇵 · Masaki Hashida🇯🇵

    We report a laboratory search for axion-like particles (ALPs) in the eV-mass range using a variable-angle three-beam stimulated resonant photon collider. The scheme independently focuses and collides three laser beams, providing a cosmology- and astrophysics-independent test. By varying the angles of incidence, the center-of-mass energy can be scanned continuously across the eV range. In this work, we operated the collider in a vacuum chamber at a large-angle configuration, verified the spacetime overlap of the three short pulses, and performed a first search centered at $m_a\simeq 2.27\mathrm{eV}$. No excess was observed. We thus set a $95\%$ C.L.\ upper limit on the pseudoscalar two-photon coupling, with a minimum sensitivity of $g/M\simeq 4.2\times 10^{-10}{\mathrm{GeV}}^{-1}$ at $m_a=2.27\mathrm{eV}$. This provides the first model-independent upper limit on the coupling that reaches the KSVZ benchmark in the eV regime and demonstrates the feasibility of eV-scale mass scans in the near future.

    ↳ hep-exastro-ph.COhep-phUniverse(2026)·1 citation
31. 31*

    Implication of multimessenger observations on the relativistic mean-field equation of state of dense nuclear matter and skin thickness of nuclei

    Rahul Kumar🇮🇳 · Prasanta Char🇪🇸 · Rana Nandi🇮🇳

    The composition and properties of infinite nuclear matter under extreme conditions of temperature and pressure remain incompletely understood. In this work, we constrain the equation of state (EoS) of nuclear matter - constructed within the framework of the Relativistic Mean Field (RMF) model - by combining results from chiral effective field theory and multimessenger observations of neutron stars. Using the saturation properties of nuclear matter, we generate a wide ensemble of EoS, which are subsequently constrained within a Bayesian framework. The resulting posterior distributions provide tight bounds on both the saturation parameters and the coupling constants of the RMF model. Our results indicate that the GW170817 event and the latest NICER observation favor a relatively soft EoS, leading to lower crust-core transition densities and thinner neutron star crusts. The radius of a $1.4M_{\odot }$ neutron star is tightly constrained to $12.508_{-0.241}^{+0.257}$ km, while the maximum mass reaches $2.174_{-0.123}^{+0.174}{M}_{\odot }$. Furthermore, our analysis reveals that the $\omega$-$\rho$ coupling, which governs the density dependence of the symmetry energy, becomes increasingly significant under successive astrophysical constraints. Finally, the predicted neutron skin thickness of ${}^{48}$Ca agrees well with the CREX measurement, whereas that of ${}^{208}$Pb remains in tension with PREX-II. In contrast to earlier studies, we do not observe a clear correlation between the neutron skin thickness of ${}^{208}$Pb and the symmetry energy slope parameter $L$.

    ↳ nucl-thhep-ph0 citations
32. 32*

    High-order cumulants and correlation functions near the critical point from molecular dynamics

    Volodymyr A. Kuznietsov🇺🇸 · Roman Poberezhniuk🇺🇦 · Mark I. Gorenstein🇺🇦 · Volker Koch🇺🇸 · Volodymyr Vovchenko🇺🇸

    We present a systematic investigation of particle number fluctuations in the crossover region near the critical endpoint of a first-order phase transition using molecular dynamics simulations of the classical Lennard-Jones fluid. We extend our prior studies to third- and fourth-order cumulants in both coordinate- and momentum-space acceptances and integrated correlation functions (factorial cumulants). We find that, even near the critical point, non-Gaussian cumulants equilibrate on time scales comparable to those of the second-order cumulants, but show stronger finite-size effects. The presence of interactions and of the critical point leads to strong deviations of the cumulants from the ideal-gas baseline in coordinate space; these deviations are expected to persist in momentum space in the presence of collective expansion. In particular, the kurtosis becomes strongly negative, $\kappa {\sigma }^2\ll -1$, on the crossover side of the critical point. However, this signal is significantly diluted once an efficiency cut used to distinguish protons from baryons is applied, leading to $|\kappa {\sigma }^2|\lesssim 1$ even in the presence of the critical point. We discuss our results in the context of ongoing measurements of proton number cumulants in heavy-ion collisions in RHIC-BES-II.

    ↳ nucl-thhep-phPRC(2026)·2 citations
33. 33*

    Massive neutrinos and interacting dark matter look alike through the lens of lensing

    Luis A. Anchordoqui🇺🇸 · Danny Marfatia🇺🇸 · Jorge F. Soriano🇺🇸

    We demonstrate that the suppression in the lensing power spectrum of the cosmic microwave background (CMB) caused by massive neutrinos can be mimicked by dark matter-baryon interactions at the precision of next-generation CMB experiments. Thus, a determination of neutrino masses from the CMB lensing power spectrum may be compromised. We illustrate the degeneracy for a dark matter-proton cross section $\propto v^{-4}$, which arises in the $t$-channel exchange of an ultralight mediator in the nonrelativistic limit.

    ↳ astro-ph.COhep-exhep-phPRD(2026)·1 citation
34. 34*

    Can we identify primordial black holes? The role of subsolar gravitational wave events

    Francesco Crescimbeni🇮🇹

    The detection of a subsolar object in a compact binary merger is regarded as one of the most compelling signatures of a population of primordial black holes (PBHs). We critically examine whether such systems can be distinguished from stellar binaries, such as those composed of neutron stars (NSs), which could also populate the subsolar mass range. Unlike PBHs, the gravitational-wave signal from stellar binaries is affected by tidal effects, which increase by several orders of magnitude as the mass decreases. We forecast the capability of current and future gravitational-wave (GW) detectors to constrain tidal effects in putative subsolar binaries. We also discuss the broader implications that the detection of a subsolar merger would have for both cosmology and nuclear physics.

    ↳ gr-qcastro-ph.HEhep-phJ.Phys.Conf.Ser.(2026)·1 citation
35. 35*

    Black holes in a dense infinite medium: a toy-model regularizing the Schwarzschild metric

    Aurélien Barrau🇫🇷 · Killian Martineau🇫🇷 · Hanane Zelgoum🇫🇷

    We revisit the dynamics of a black hole accreting energy from a surrounding homogeneous and infinite space. We argue for a simple heuristic modification of the Schwarzschild approximation when the density of the medium is not negligible anymore. The resulting behavior is drastically modified: the mass divergence at finite time is cured and the thermodynamical properties are deeply changed. Some potential consequences for quantum gravity and bouncing models are also pointed out. Those conclusions being mostly obtained from a Newtonian approach, they only aim at guiding toward a more rigorous treatment. Still, interestingly, the behavior is far more convincing that the one usually obtained.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-phMod.Phys.Lett.A(2026)·1 citation
36. 36*

    Systematics of the chemical freeze-out line in the high baryon density regime explored at SIS100

    Emma Lilith Hofmann🇩🇪 · Tom Reichert🇺🇸 · Volodymyr Vovchenko🇺🇸 · Jan Steinheimer🇩🇪 · Marcus Bleicher🇩🇪

    The systematic uncertainties of chemical freeze-out fits at SIS100 energies (Au+Au reactions at $\sqrt{s_{NN}}=3-5$ GeV) are studied using UrQMD simulations. Although hadron production in UrQMD does not occur on a sharp chemical freeze-out hyper-surface, the extracted fit quality is shown to be very good. The extracted chemical parameters depend on the selected hadron species as well as the underlying equation of state (EoS) of the matter. Including light nuclei and anti-protons in the fit increases the expected freeze-out temperature, while a stiffer EoS increases the obtained chemical potential. Similarly, the baryon densities extracted by the thermal fits depend on the choice of hadrons as well as the underlying equation of state. These results are important for the upcoming CBM@FAIR physics program and highlight that a degree of caution is advised when one relates the chemical freeze-out curve to features on the QCD phase diagram like the critical endpoint or a possible phase transition.

    ↳ nucl-thhep-phEur.Phys.J.ST(2026)·0 citations
37. 37*

    Shadow of Extreme Compact Charged Objects in Consistent 4-Dimensional Einstein-Gauss-Bonnet Gravity

    Sara Saghafi🇮🇷 · Kourosh Nozari🇮🇷 · Maryam Kaveh🇮🇷

    In order to better describe gravitational phenomena on both very small and cosmological scales, there have been constant attempts to generalize and expand the theory of General Relativity (GR) since its inception. The Einstein Gauss Bonnet (EGB) theory is one such extension that adds spacetime corrections related to curvature. Since the standard Gauss Bonnet term is purely topological, it does not contribute to the field equations in four dimensions. To get around this restriction, however, an invariant four dimensional limit has been developed. In this work, we study Extreme Compact Charged Objects (ECCOs), which can resemble black holes, in a gravity framework that is compatible with Einstein Gauss Bonnet in four dimensions. Our main goal is to compare theoretical predictions with Event Horizon Telescope (EHT) observational data in order to constrain the Gauss Bonnet coupling constant {\alpha}. In order to achieve this, we investigate important optical characteristics like the shadow, light bending angle, and other associated observables, as well as the geodesic structure of ECCO spacetimes in EGB gravity. Finally, we apply these findings to constrain the Gauss Bonnet constant.

    ↳ gr-qchep-phhep-thInt.J.Geom.Meth.Mod.Phys.(2026)·2 citations
38. 38*

    Running of the spectral index: Reconciling the CMB with the Lyman-$\alpha$ Forest

    Malcolm Fairbairn🇬🇧 · Lucien Heurtier🇬🇧 · María Olalla Olea-Romacho🇬🇧

    We investigate the scale dependence of the primordial power spectrum by combining \Planck, ACT DR6, SPT-3G, and eBOSS Lyman-$\alpha$ forest data, extending sensitivity to smaller comoving scales than those probed by the CMB alone. Within a parametrisation based on a Taylor expansion around the pivot scale, we constrain the running of the spectral index ${\alpha }_s$ and its running ${\beta }_s$. By using eBOSS likelihoods exhibiting a suppression of small-scale power either in amplitude or spectral index, we show that the latter can be accommodated by correlated variations of $({\alpha }_s,{\beta }_s)$, leading to a preference for non-zero running. We show that inflationary potentials with localised features -- such as Gaussian dips, bumps, or axion-monodromy modulations -- can reproduce the inferred scale dependence while remaining compatible with current CMB constraints. We release the public {\tt PIPE} code to enable systematic tests of inflationary potentials against current CMB datasets.

    ↳ astro-ph.COhep-phPRD(2026)·6 citations
39. 39*

    Precision lattice calculation of the hadronic contribution to the running of the electroweak gauge couplings

    Alessandro Conigli🇩🇪 · Dalibor Djukanovic🇩🇪 · Georg von Hippel🇩🇪 · Simon Kuberski🇨🇭 · Harvey B. Meyer🇩🇪 · Kohtaroh Miura🇯🇵 · Konstantin Ottnad🇩🇪 · Andreas Risch🇩🇪 · Hartmut Wittig🇩🇪

    We present an update of our lattice QCD determination of the hadronic contribution to the running of the electromagnetic coupling, $\Delta {\alpha }_{\mathrm{had}}^{(5)}(-Q^2)$, and of the electroweak mixing angle in the space-like momentum region up to $Q^2=12{\mathrm{GeV}}^2$. The calculation is based on CLS ensembles with $N_f=2+1$ flavours of $O(a)$-improved Wilson fermions, covering five lattice spacings between $0.039$ and $0.085$ fm and a range of pion masses, including the physical point. A refined analysis employing a telescopic window strategy allows for a clean separation of systematic effects across Euclidean distance scales. Statistical precision is further enhanced through low-mode averaging, combined with a spectral reconstruction of the vector-vector correlator at long distances on the most chiral ensembles. We confirm significant tensions of up to $7\sigma$ at space-like virtualities around $Q^2=1{\mathrm{GeV}}^2$ between our lattice results for $\Delta {\alpha }_{\mathrm{had}}^{(5)}(-Q^2)$ and the corresponding data-driven estimates based on $e^{+}{e}^{-}$ cross section data. Combining our lattice data with perturbative QCD via the Euclidean split technique, we obtain at the $Z$-pole $\Delta {\alpha }_{\mathrm{had}}^{(5)}(M_Z^2)=0.027813(33{)}_{\mathrm{lat}}(35{)}_{\mathrm{pQCD}}$, which is more than two times more precise than recent data-driven estimates. Our result deviates slightly, by $1-2\sigma$, from the value produced by global electroweak fits. For the electroweak mixing angle, we present the hadronic contribution to its running and provide a precise determination of the octet-singlet mixing component ${\bar{\Pi }}^{(0,8)}$, in good agreement with phenomenological models but with significantly higher precision.

    ↳ hep-lathep-phPRD(2026)·9 citations
40. 40*

    Accretion Process as a Probe of Extra Dimensions in MOG Compact Object Spacetimes

    Kourosh Nozari🇮🇷 · Sara Saghafi🇮🇷 · Zeynab Ramezanpasandi🇮🇷

    The idea of extra spatial dimensions arises from attempts to unify gravity with other fundamental interactions, develop a consistent theory of quantum gravity, and address open problems in particle physics and cosmology. Considerable attention has been devoted to understanding how such dimensions modify gravitational theories. One way to probe their impact is through the analytical study of astrophysical processes such as black hole accretion. Since accretion efficiently converts gravitational energy into radiation, this makes it a powerful tool to test modified gravity (MOG) theories and higher-dimensional frameworks via the behavior of dark compact objects like black holes, neutron stars, and white dwarfs. In this work, we investigate the dynamics of neutral particles around a higher-dimensional, regular, spherically symmetric MOG compact object, focusing on the innermost stable circular orbit (ISCO), energy flux, temperature, and differential luminosity. We further analyze the accretion of a perfect fluid onto the same object, deriving analytical expressions for the four-velocity and proper energy density of the inflowing matter. Our findings show that extra dimensions reduce the ISCO radius while enhancing the corresponding flux and temperature. Finally, by comparing the effective disk temperature $T_{\text{eff}}$ with Event Horizon Telescope (EHT) observations of Sgr A*, we argue that MOG and higher-dimensional corrections to the accretion disk properties could be close to the current threshold of detectability.

    ↳ gr-qchep-phhep-thEPJC(2025)·3 citations
41. 41*

    Search for Diffuse Galactic Neutrinos with the Full ANTARES Telescope Dataset

    ANTARES Collaboration · Pedro De la Torre Luque · Daniele Gaggero · Dario Grasso · Giulia Pagliaroli · Vittoria Vecchiotti · Francesco Lorenzo Villante

    The diffuse emission of gamma-rays and neutrinos, produced by interactions of cosmic rays with interstellar matter in the Milky Way, provides valuable insights into cosmic ray propagation and Galactic processes. Emission models incorporating different assumptions about cosmic ray diffusion, source distribution, and target gas density are tested using data from neutrino telescopes. In this study, the final all-flavor neutrino dataset, collected over 15 years (2007--2022) by the ANTARES neutrino telescope, is analyzed. A maximum likelihood ratio method built to handle templates of Galactic emission models is employed to evaluate the compatibility of these models with the observed spatial and energy distributions of neutrino events. The results do not yield stringent constraints on the tested models and upper limits on the diffuse neutrino flux are derived, which are compatible with the results obtained by other experiments.

    ↳ astro-ph.HEastro-ph.GAhep-exhep-phJHEAp(2026)·5 citations
42. 42*

    Gravitational Wave Spectral Shapes as a probe of Long Lived Right-handed Neutrinos, Leptogenesis and Dark Matter: Global versus Local B-L Cosmic Strings

    Satyabrata Datta🇨🇳 · Anish Ghoshal🇵🇱 · Angus Spalding🇬🇧 · Graham White🇬🇧

    The scale of the seesaw mechanism is typically much larger than the electroweak scale. This hierarchy can be naturally explained by $U(1{)}_{B-L}$ symmetry, which after spontaneous symmetry breaking, simultaneously generates Majorana masses for neutrinos and produces a network of cosmic strings. Such strings generate a gravitational wave (GW) spectrum which is expected to be almost uniform in frequency unless there is a departure from the usual early radiation domination. We explore this possibility in Type I, II and III seesaw frameworks, finding that only for Type-I, long-lived right-handed neutrinos (RHN) may provide a period of early matter domination for parts of the parameter space, even if they are thermally produced. Such a period leaves distinctive imprints in the GW spectrum in the form of characteristic breaks and a knee feature, arising due to the end and start of the periods of RHN domination. These features, if detected, directly determine the mass $M$, and effective neutrino mass $\tilde{m}$ of the dominating RHN. We find that GW detectors like LISA and ET could probe RHN masses in the range $M\in [0.1,10^9]$ GeV and effective neutrino masses in the $\tilde{m}\in [10^{-10},10^{-8}]$ eV range. We investigate the phenomenological implications of long-lived right-handed neutrinos for both local and global $U(1{)}_{B-L}$ strings, focusing on dark matter production and leptogenesis. We map the viable and detectable parameter space for successful baryogenesis and asymmetric dark matter production from right-handed neutrino decays. We derive analytical and semi-analytical relations correlating the characteristic gravitational-wave frequencies to the neutrino parameters $\tilde{m}$ and $M$, as well as to the relic abundances of dark matter and baryons.

    ↳ astro-ph.COhep-phJHEP(2026)·13 citations
43. 43*

    Three-dimensional sizes and shapes of pion emission in heavy-ion collisions

    Daniel Kincses🇭🇺 · Emese Arpasi🇭🇺 · Laszlo Kovacs🇭🇺 · Marton Nagy🇭🇺 · Mate Csanad🇭🇺

    In the era of precision measurements in high-energy heavy-ion physics, there is an increasing expectation towards phenomenological and theoretical studies to provide a better description of data. In recent years, multiple experiments have confirmed through two-pion Bose-Einstein correlation measurements that the shape of the two-pion pair source can be well described by Levy-stable distributions. However, direct comparisons of new phenomenological results with the data are still needed to understand the underlying phenomena and learn more about the nature of pion emission. In this paper, we present a three-dimensional analysis of the two-pion source in Monte-Carlo simulations of Au+Au collisions at 200 GeV per nucleon collision energy, and discuss a detailed comparison with the most recent centrality-dependent measurements from the PHENIX Collaboration.

    ↳ nucl-exhep-phnucl-thEPJC(2026)·5 citations
44. 44*

    Skewness-dependent moments of the pion GPD from nonlocal quark-bilinear correlators

    Xiang Gao🇺🇸 · Swagato Mukherjee🇺🇸 · Qi Shi🇺🇸 · Fei Yao🇺🇸 · Yong Zhao🇺🇸

    We present lattice QCD calculations of the odd Mellin moments of pion valence-quark generalized parton distribution (GPD) up to fifth order, $⟨x^4⟩$, and for the skewness range $[-0.33,0]$ using operator product expansion of bilocal quark-bilinear operators. The calculations are performed on an ensemble with lattice spacing $a=0.04\mathrm{fm}$ and valence pion mass $300$ $\mathrm{MeV}$, employing boosted pion states with momenta up to 2.428 GeV and momentum transfers reaching 2.748 GeV${}^2$. We employ ratio-scheme renormalization and next-to-leading-logarithmic resummed perturbative matching. At zero skewness, our results are consistent with previous lattice studies. By combining matrix elements at multiple values of skewness and momentum transfer, skewness-dependent moments are obtained through simultaneous polynomiality-constrained fits.

    ↳ hep-lathep-phnucl-exnucl-thPRD(2026)·14 citations
45. 45*

    Accurate and Efficient Emulation of Proton-Deuteron Scattering via the Reduced Basis Method and Active Learning

    Alex Gnech🇺🇸 · Xilin Zhang🇺🇸 · Christian Drischler🇺🇸 · R. J. Furnstahl🇺🇸 · Alessandro Grassi🇮🇹 · Alejandro Kievsky🇮🇹 · Laura E. Marcucci🇮🇹 · Michele Viviani🇮🇹

    We introduce highly accurate and efficient emulators for proton-deuteron scattering below the deuteron breakup threshold. We explore two different reduced-basis method strategies: one based on the Kohn variational principle and another on Galerkin projections of the underlying system of linear equations. We use the adaptive greedy algorithm previously developed for two-body scattering for optimal selection of high-fidelity training points in the input parameter space. We demonstrate that these emulators reproduce ab initio hyperspherical harmonics calculations of $R$-matrix elements with remarkable precision, achieving relative errors as low as $10^{-7}$ with a small number of training points, even in regions of strong nonlinear parameter dependence. They also dramatically accelerate the exploration of the scattering predictions in the parameter space, a capability highly desired for calibrating (chiral) three-nucleon forces against scattering measurements. Our formalism can be further generalized to handle nucleon-deuteron scattering above the breakup threshold. These emulator developments will provide valuable tools to accelerate uncertainty quantification and rigorous parameter inference in the study of nuclear forces.

    ↳ nucl-thhep-phnucl-ex6 citations
46. 46*

    Entanglement asymmetry in gauge theories: chiral anomaly in the finite temperature massless Schwinger model

    Adrien Florio🇩🇪 · Sara Murciano🇫🇷

    The entanglement asymmetry has emerged in recent years as a practical quantity to study phases of matter. We present the first study of entanglement asymmetry in gauge theories by considering the chiral anomaly of the analytically solvable massless Schwinger model at both zero and finite temperatures. At zero temperature, we find the asymmetry exhibits logarithmic growth with system size. At finite temperature, we show that it is parametrically more sensitive to chiral symmetry-breaking than the corresponding local order parameter: while the chiral condensate decays exponentially, the asymmetry decreases only logarithmically. This establishes the entanglement asymmetry as a promising tool to probe (finite-temperature) phase transitions in gauge theories.

    ↳ hep-thcond-mat.stat-mechhep-phnucl-th+1PRD(2026)·11 citations
47. 47*

    A short blanket for cosmology: the CMB lensing anomaly behind the preference for a negative neutrino mass

    Andrea Cozzumbo🇮🇹 · Mattia Atzori Corona🇮🇹 · Riccardo Murgia🇮🇹 · Maria Archidiacono🇮🇹 · Matteo Cadeddu🇮🇹

    Recent analyses combining cosmic microwave background (CMB) and baryon acoustic oscillation (BAO) challenge particle physics constraints on the total neutrino mass, pointing to values smaller than the lower limit from neutrino oscillation experiments. To examine the impact of different CMB likelihoods from $Planck$, lensing potential measurements from $Planck$ and ACT, and BAO data from DESI, we introduce an effective neutrino mass parameter ($\sum {\tilde{m}}_{\nu }$) which is allowed to take negative values. We investigate its correlation with two extra parameters capturing the impact of gravitational lensing on the CMB: one controlling the smoothing of the peaks of the temperature and polarization power spectra; one rescaling the lensing potential amplitude. In this configuration, we infer $\sum {\tilde{m}}_{\nu }=-0.018_{-0.089}^{+0.085}\text{eV}(68\%\text{C.L.})$, which is fully consistent with the minimal value required by neutrino oscillation experiments. We attribute the apparent preference for negative neutrino masses to an excess of gravitational lensing detected by late-time cosmological probes compared to that inferred from $Planck$ CMB angular power spectra. We discuss implications in light of the DESI BAO measurements and the CMB lensing anomaly.

    ↳ astro-ph.COhep-ph11 citations
48. 48*

    Gravitational waves from parabolic encounters: A study of linear and nonlinear memory

    Samik Dutta🇧🇷 · Ankur Chhabra🇮🇳 · Aritra Banerjee🇮🇳 · Sajal Mukherjee🇮🇳 · Subhendra Mohanty🇮🇳

    The memory effect is known to introduce a permanent displacement in the gravitational wave (GW) detectors after the passage of a GW signal. While the $\text{linear memory}$ adheres to the source properties, the $\text{non-linear memory}$ is a secondary effect sourced by the GW itself. In the present work, we discuss GW signals with both these kinds of memory effects, while focusing on the parabolic limit of an encounter. This special case is theoretically intriguing and emerges as a limiting situation for both eccentric and hyperbolic events. However, in this paper, we argue that a simple extrapolation of memory calculations for eccentric or hyperbolic cases to the parabolic case may lead to incorrect estimations. Therefore, we treat the parabola as a special case and use an intrinsic parameterization, with which we calculate gravitational wave signals and their energy spectrum via an effective field theory formalism. Unlike the hyperbolic case, which is known to have linear memory, we notice that parabolic encounters bring out new features in the zero frequency limit (ZFL). The exactly parabolic case is studied here primarily as an idealized separatrix between bound and unbound motion, and our analysis highlights some of the key challenges and salient aspects of GW memory in this regime.

    ↳ gr-qchep-phhep-thPRD(2026)·1 citation
49. 49*

    Gradient RG Flow in Scalar-Fermion QFTs

    William H. Pannell🇬🇧 · William Patrick Ronayne🇬🇧 · Andreas Stergiou🇬🇧

    The gradient property of the renormalisation group (RG) is examined to four-loop order in scalar-fermion systems in $d=4$ and $d=4-\epsilon$ dimensions. The crucial role played by the beta shift, which is a modification of the standard dim-reg beta function, is elucidated, and specific conditions that it needs to satisfy for the RG flow to be gradient are derived. Over a thousand gradient-flow conditions are found, all of which are scheme-independent and satisfied whenever the full set of results needed to check them is available. It is shown, in the framework of the $\epsilon =4-d$ expansion, that the space of conformal field theories (CFTs) is dominated by those with non-zero beta shift as the number of fields grows. Physical properties of CFTs obtained as solutions where the beta functions are not zero in the $\epsilon$ expansion are discussed.

    ↳ hep-thcond-mat.stat-mechhep-phJHEP(2026)·5 citations

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