Tue·May 13, 2025Tuesday·May 13, 2025

1. 01*

   Probing light neutralinos from pair-produced sleptons with displaced vertices at the high-luminosity LHC

   Giovanna Cottin🇨🇱 · Juan Carlos Helo🇨🇱 · Fabián Hernández-Pinto🇨🇱 · Nicolás A. Neill🇨🇱 · Zeren Simon Wang🇨🇳

   We study light neutralinos (${\tilde{\chi }}_1^0$) with masses ranging from 10 GeV to several hundred GeV within the framework of R-parity-violating (RPV) supersymmetry. These light neutralinos can be long-lived, decaying with a macroscopic displacement (order cm) inside the LHC main detectors. Complementing previous works on the subject, here we focus on their production through the electroweak pair production of left-chiral sleptons (${\tilde{e}}_L$), with the signal process $pp\to {\tilde{e}}_L^{+}{\tilde{e}}_L^{-}\to e^{+}{\tilde{\chi }}_1^0{e}^{-}{\tilde{\chi }}_1^0$. In contrast to the previous study with a singly produced slepton, where the RPV coupling ${\lambda }_{111}^{\prime }$ induces both the production and decay of the light neutralino, in our scenario the production proceeds through Drell-Yan-like processes that are essentially independent of RPV couplings. Correspondingly, we implement a displaced-vertex search strategy for which our numerical analysis shows that the high-luminosity LHC can probe ${\lambda }_{111}^{\prime }$ values up to three orders of magnitude smaller, and neutralino masses up to about four times larger than those accesible in the previously studied single-slepton production scenario.

   hep-phJHEP(2025)·3 citations
2. 02*

   Electroweak Triplet Scalar Contribution to $SO(10)$ Leptogenesis

   Chee Sheng Fong🇧🇷 · Ketan M. Patel🇮🇳

   We show that electroweak triplet scalar can significantly impact baryogenesis via leptogenesis in concrete and predictive $SO(10)$ GUTs, even when light neutrino masses arise predominantly from the type-I seesaw mechanism. This is illustrated within a minimal renormalisable $SO(10)$ model with $10$ and $\overline{126}$ scalars in the Yukawa sector and a global Peccei-Quinn-like symmetry. The quark-lepton unification and the flavour structure of the fundamental Yukawa couplings enforce type-I dominance in the light neutrino masses, also suppressing the triplet-induced CP asymmetries in the right-handed neutrino decays. However, the triplet's own decays introduce a new CP-violating source, which can enhance or suppress the total baryon asymmetry. For triplet mass near the right-handed neutrino mass scale, this contribution can dominate, making it essential in assessing the viability of $SO(10)$ leptogenesis scenarios.

   hep-phJHEP(2025)·6 citations
3. 03*

   RGE solver for the complete dim-7 SMEFT interactions and its application to $0\nu \beta \beta$ decay

   Yi Liao🇨🇳 · Xiao-Dong Ma🇨🇳 · Hao-Lin Wang🇨🇳 · Xiang Zhao🇨🇳

   We present an automatic renormalization group equations (RGEs) solver, D7RGESolver, designed for the precise numerical solution of one-loop RGEs of dimension-7 (dim-7) operators within the standard model effective field theory (SMEFT). This tool is capable of calculating the RGE effects of dim-5 and dim-7 SMEFT operators between any two scales above the electroweak scale. We take the nuclear neutrinoless double beta ($0\nu \beta \beta$) decay process as an example to appreciate the importance of the running effects in phenomenological studies. Our analysis demonstrates that $0\nu \beta \beta$ decay can constrain nearly all dim-7 SMEFT operators involving first-generation leptons that violate lepton number by two units, after accounting for RGE effects. Specifically, we have placed meaningful constraints on 55 dim-7 Wilson coefficients, compared to only 10 from a simple tree-level analysis. Certain operators exhibit much stricter constraints when RGE effects are included, especially for the operators that mix with neutrino mass operators. We provide a complete code documentation for D7RGESolver, along with examples of its usage and interfacing with external automated codes for calculating $0\nu \beta \beta$ decay. The D7RGESolver code is available at: \href{https://github.com/ZhaoXiang210/D7RGESolver}{Github: D7RGESolver}

   hep-phJHEP(2025)·5 citations
4. 04*

   Using neutron stars to probe dark matter charged under a $L_{\mu }-L_{\tau }$ symmetry

   Nicole F. Bell🇦🇺 · Giorgio Busoni🇦🇺 · Avirup Ghosh🇦🇺

   Kinetic heating of old cold neutron stars, via the scattering of dark matter with matter in the star, provides a promising way to probe the nature of dark matter interactions. We consider a dark matter candidate that is a Standard Model singlet Dirac fermion, charged under a $U(1{)}_{L_{\mu }-L_{\tau }}$ symmetry. Such dark matter interacts with quarks and electrons only via loop-induced couplings, and hence is weakly constrained by direct-detection experiments and cosmic-microwave background observations. However, tree-level interactions with muons enable the dark matter to interact efficiently with the relativistic muon component of a neutron star, heating the star substantially. Using a fully relativistic approach for dark matter capture in the star, we show that observations of old cold neutron stars can probe a substantial, yet unexplored, region of parameter space for dark matter masses in the range 100 MeV - 100 GeV.

   hep-phJCAP(2025)·7 citations
5. 05*

   Implementing Errors on Errors: Bayesian vs Frequentist

   Satoshi Mishima🇯🇵 · Kin-ya Oda🇯🇵

   When combining apparently inconsistent experimental results, one often implements errors on errors. The Particle Data Group's phenomenological prescription offers a practical solution but lacks a firm theoretical foundation. To address this, D'Agostini and Cowan have proposed Bayesian and frequentist approaches, respectively, both introducing gamma-distributed auxiliary variables to model uncertainty in quoted errors. In this Letter, we show that these two formulations admit a parameter-by-parameter correspondence, and are structurally equivalent. This identification clarifies how Bayesian prior choices can be interpreted in terms of frequentist sampling assumptions, providing a unified probabilistic framework for modeling uncertainty in quoted variances.

   hep-phastro-ph.IMhep-exstat.MEEPJC(2025)·0 citations
6. 06*

   The Generalized Uncertainty Principle. New Bounds and Trends

   Ezequiel Valero🇪🇸 · Hector Gisbert🇪🇸 · Victor Ilisie🇪🇸

   The Heisenberg uncertainty principle is one of the fundamental pillars of quantum mechanics and quantum field theory. It is normally introduced by postulating the commutation relations $[{\hat{x}}^i,{\hat{p}}^j]=i\hslash {\delta }^{ij}$. However, as suggested by some quantum gravity models and string theory, this basic principle no longer holds true in the presence of a minimal length, possible the Plank length, and modifications of the commutation have been proposed i.e., of the form $[{\hat{x}}^{\mu },{\hat{p}}^{\nu }]=-i\hslash (1+{\beta }_0{\hat{p}}^2/{\Lambda }^2){\eta }^{\mu \nu }$(plus possible additional terms). In this work we will consider the previous modified uncertainty principle in terms of an effective field theory, comment upon some theoretical subtleties that are often overlooked in the literature, and constrain, for the first time, the $\Lambda$ scale with the Compton high-energy experimental data. Our findings suggest that high-energy experiments are potentially sensitive to these corrections and could serve as an effective framework for probing possible violations of the Heisenberg uncertainty principle

   hep-phClass.Quant.Grav.(2026)·2 citations
7. 07*

   Six-dimensional light-front Wigner distributions of the proton

   Yirui Yang🇨🇳 · Tianbo Liu🇨🇳 · Bo-Qiang Ma🇨🇳

   We investigate six-dimensional quark Wigner distributions of the proton in a light-front quark spectator-diquark model. Benefiting from the light-front boost-invariant longitudinal variable $\tilde{z}$, these light-front Wigner distributions provide complete information of parton distribution in the phase space and the correlation with spins. At the leading twist, one can define 16 independent distribution functions in according to different combinations of quark and proton polarizations. Numerical results of all these Wigner distributions are presented, unraveling rich structures of the proton, which may potentially provide new observables to be explored at future experiments.

   hep-phEPJC(2025)·5 citations
8. 08*

   Approximate Minimal SU(5), Several Fundamental Scales, Fluctuating Lattice

   Holger Bech Nielsen🇩🇰

   Having shortly reviewed our idea of the grand unified SU(5) being only exact in a classical limit, in a truly existing lattice, an ontological lattice, we go over to putting a series of different physical energy scales such the approximate unification scale for the SU(5)(without any SUSY), the Planck scale, and e.g. the scale of see-saw neutrino masses into a certain plot showing the energy scales on a straight line. This straight line of this plot supposed to result from such an ontological lattice, that fluctuates in link size a and lattice density in a very strong way according to a log normal distribution. The point is that different energy scales result from the link size of the lattice to different powers, like the averages a to the n th , where the power n depends on the type of scale considered. Since the n th root of the average of the n th power of the link size in the fluctuating lattice is very strongly dependent on the power n, because of very huge fluctuations, the different types of physical energy scales can get very different. With a Galton i.e. log normal distribution of the link size the various energy scales have their logarithms fall into a nice straight line versus the power of the link size, on which they depend. Our model gives a surprisingly good number for the small deviations of the experimental electron-and muon-anomalous magnetic moment from the pure Standard Model value.

   hep-phhep-latPoS(2025)·2 citations
9. 09*

   Flavor-Dependent Dynamical Spin-Orbit Coupling in Light-Front Holographic QCD: A New Approach to Baryon Spectroscopy

   Fidele J. Twagirayezu🇺🇸

   In this article, we propose a novel extension of Light-Front Holographic Quantum Chromodynamics (QCD) to study the effects of spin-orbit coupling on the baryon spectrum by introducing a flavor-dependent dynamical spin-orbit potential. This potential, modulated by the holographic coordinate and quark flavor, accounts for the mass hierarchy of quarks and the nonperturbative dynamics of confinement. By incorporating an exponentially decaying coupling that varies with the confinement scale, we capture the interplay between short-distance and long-distance spin-orbit interactions, particularly for heavy-light baryons. An optional coupling to holographic glueball fields further enriches the model, introducing nonperturbative QCD effects. The resulting modified light-front wave equation predicts flavor-dependent mass splittings and Regge trajectories, offering improved descriptions of both light and heavy baryon spectra. We discuss the implementation, parameter fitting, and testable predictions for experimental validation, particularly for heavy baryons observed at LHCb and Belle II. This approach bridges light and heavy quark dynamics, advancing the holographic modeling of baryon spectroscopy.

   hep-phFew Body Syst.(2026)·2 citations
10. 10*

    Pseudoscalar Meson Parton Distributions Within Gauge-Invariant Nonlocal Chiral Quark Model

    Parada T. P. Hutauruk🇰🇷

    In this paper, I investigate the gluon distributions for the kaon and pion, as well as the improvement of the valence-quark distributions, in the framework of the gauge-invariant nonlocal chiral quark model (NL$\chi$QM), where the momentum dependence is taken into account. I then compute the gluon distributions for the kaon and pion that are dynamically generated from the splitting functions in the DGLAP QCD evolution. In a comparison with the recent lattice QCD and JAM global analysis results, it is found that the results for the pion gluon distributions at $Q=$ 2 GeV, which is set based on the lattice QCD, have a good agreement with the recent lattice QCD data; this is followed up with the up valence-quark distribution of the pion results at $Q=$ 5.2 GeV in comparison with the reanalysis experimental data. The prediction for the kaon gluon distributions at $Q=2$ GeV is consistent with the recent lattice QCD calculation.

    hep-phnucl-thSymmetry(2025)·6 citations
11. 11*

    Searching for dark matter annihilation in the Sun with the IceCube Upgrade

    Dan Hooper🇺🇸 · Fabrizio Vassallo🇺🇸

    The IceCube Upgrade will provide unprecedented sensitivity to dark matter particles annihilating in the core of the Sun. For dark matter candidates with spin-dependent couplings to nuclei and that annihilate significantly to tau leptons or neutrinos, we find that the IceCube Upgrade will be capable of testing parameter space that is beyond the reach of existing direct detection experiments. After calculating the sensitivity of the IceCube Upgrade to dark matter annihilation in the Sun, we explore dark matter models that could be tested by this experiment, identifying two classes of scenarios as promising targets for such searches.

    hep-phastro-ph.COastro-ph.HEPRD(2025)·6 citations
12. 12*

    Hadroproduction data support tetraquark hypothesis for ${\chi }_{c1}(3872)$

    Wai Kin Lai🇨🇳 · Hee Sok Chung🇰🇷

    We show that the recently proposed tetraquark hypothesis for the nature of the ${\chi }_{c1}(3872)$ results in a formalism for inclusive production rates that has no unknown parameters. We employ this formalism to compute hadroproduction rates of ${\chi }_{c1}(3872)$ at the Large Hadron Collider, which agree with measured prompt and nonprompt cross sections. Thus we find that the tetraquark hypothesis for ${\chi }_{c1}(3872)$ is well supported by hadroproduction data.

    hep-phPRD(2025)·8 citations
13. 13*

    One-loop corrections to the neutrino in the N-B-LSSM

    Shuang Di🇨🇳 · Shu-Min Zhao🇨🇳 · Ming-Yue Liu🇨🇳 · Xing-Yu Han🇨🇳 · Song Gao🇨🇳 · Xing-Xing Dong🇨🇳

    In this paper, we study one-loop corrections to the neutrino mass matrix in the N-B-LSSM. We obtain the N-B-LSSM from the $U(1)$ extension of the minimal supersymmetric standard model(MSSM). By adding three generation right-handed neutrino superfields and three Higgs singlets, the model generates tiny neutrino masses at the tree level through the first type seesaw mechanism. However, one-loop corrections are essential for understanding neutrino masses and mixing angles. In our calculations, the one-loop corrections contribute approximately 10\% to the total result. We calculate the neutrino mass variance and mixing angle from both normal order neutrino mass spectrum and inverse order neutrino mass spectrum. Crucially, these corrections are 3-5 times larger than current experimental uncertainties. And they have implications for future neutrino oscillation experiments. This study provides new theoretical support for exploring the mechanism of neutrino mass generation in the supersymmetric model and provides clues for exploring new physics beyond the Standard Model (SM).

    hep-phJHEP(2025)·1 citation
14. 14*

    A $p_T$-ratio observable for studies of intrinsic transverse momentum of partons from Drell-Yan $p_T$ spectra

    Wenxiao Zhan🇨🇳 · Siqi Yang🇨🇳 · Minghui Liu🇨🇳 · Liang Han🇨🇳 · Francesco Hautmann🇬🇧

    The determination of the intrinsic transverse momentum distribution of partons is central both for applications of parton shower Monte Carlo generators and for QCD studies of transverse momentum dependent (TMD) parton densities. Valuable information on this distribution is provided by experimental measurements of Drell-Yan transverse momentum $p_T$, in the region of low transverse momenta, with fine binning in $p_T$. However, such fine-binning measurements are challenging, as they require an extremely delicate control of systematic uncertainties. We suggest a $p_T$ observable based on measuring ratios between cross sections of suitably defined low-$p_T$ and high-$p_T$ regions. This observable does not rely on any dedicated partition of bins and has lower systematic uncertainties, and is shown to provide a good sensitivity to the intrinsic transverse momentum.

    hep-ph4 citations
15. 15*

    Instability of quantum fluctuation around classical nonlinear massive wave solution in Higgs potential and particle creations

    Yoshio Kitadono🇹🇼 · Tomohiro Inagaki🇯🇵

    We discuss the dynamics of the quantum fluctuation around the nonlinear massive wave solution in the Higgs potential. In particular, we analyze the stability and instability of the mode function. Using the stability condition for Hill's equation, we obtain the instability region of the mode function in the quantum fluctuation as the function of the parameters in the mode equation. We show that the two types of the instabilities of the system in the particle number can be understood by the Floquet's exponents in the instability parameter region. The analysis will be useful to understand the dynamics of the quantum field theory around the nonlinear massive wave solution when the classical background slightly deviates from the constant background during the middle stage of the phase transition.

    hep-phPRD(2025)·1 citation
16. 16*

    $\varphi$ meson properties in dense resonance matter at finite temperature

    Manpreet Kaur🇮🇳 · Arvind Kumar🇮🇳

    The effective mass and decay width of the $\varphi$ meson in the isospin asymmetric hot and dense resonance matter are studied using the effective Lagrangian framework considering the $\varphi K\bar{K}$ interactions at one-loop level. In addition to spin$-1/2$ octet baryons, we consider the effect of resonances ${\Delta }^{++,+,0,-},{\Sigma }^{\ast \pm ,0},{\Xi }^{\ast 0,-},{\Omega }^{-}$, on the properties of $\varphi$ meson. The in-medium effects on the $\varphi$ meson properties are simulated through the effective masses of kaons and antikaons computed using the chiral SU(3) hadronic mean field model in the presence of resonance baryons. The loop integral appearing in the computation of $\varphi$ meson self energies is regularized using the dipole form factor with a cutoff parameter. The presence of resonance baryons within the medium at finite temperature is observed to significantly modify the effective mass and decay width of $\varphi$ mesons. Examining the $\varphi$ meson masses and decay width within a dense medium is anticipated to be essential for understanding experimental results from heavy-ion collision experiments.

    hep-phnucl-thPRD(2025)·5 citations
17. 17*

    Imperfect Axions

    Luca Di Luzio🇮🇹

    In this contribution, I'll discuss two classes of effects--additional sources of CP violation and PQ breaking--that offer a slightly different take on axion physics. Both are tied to the idea that the axion solution to the strong CP problem might not be exact, hence the title ``Imperfect Axions''.

    hep-ph1 citation
18. 18*

    CP Violation in Hadronic Weak Decays of Charmed Baryons in the Topological Diagrammatic Approach

    Hai-Yang Cheng🇹🇼 · Fanrong Xu🇨🇳 · Huiling Zhong🇨🇳

    CP violation in the charmed baryon sector is generally expected to be very small, of order $10^{-4}$ or even smaller. Nevertheless, large long-distance penguin topologies can be induced through final-state rescattering. At the hadron level, they are manifested as the triangle and bubble diagrams. However, these diagrams consist of not only the penguin but also other tree topologies. Therefore, we focus on the flavor structure of the these diagrams and project out their contributions to penguin and tree topologies. The analysis is performed within the framework of the topological diagram approach and the irreducible SU(3) approach in which the SU(3) flavor symmetry of QCD is realized to describe the nonleptonic decays of charmed baryons. CP violation at the per mille level is found in the following decay modes: ${\Lambda }_c^{+}\to p{\pi }^0,{\Lambda }_c^{+}\to p{\eta }^{\prime },{\Xi }_c^0\to {\Sigma }^0\eta$ and ${\Xi }_c^{+}\to {\Sigma }^{+}\eta$. CP asymmetries in the last three modes receive sizable contributions from the SU(3)-flavor-singlet hairpin diagram.

    hep-phhep-exPRD(2025)·11 citations
19. 19*

    Enhancement of photon emission rate near QCD critical point

    Yukinao Akamatsu🇯🇵 · Masayuki Asakawa🇯🇵 · Masaru Hongo🇯🇵 · Mikhail Stephanov🇺🇸 · Ho-Ung Yee🇺🇸

    We compute photon emission rate enhancement near the QCD critical point using an effective theory of dynamic critical phenomena and derive a universal photon spectrum. The emission rate scales similarly to conductivity, increasing with the correlation length ($\xi$), diverging at the critical point. The spectrum exhibits $\omega d{N}_{\gamma }/d^{3}k\propto {\omega }^{-1/2}$ in the scaling regime, with the transition occurring at a frequency comparable to shear damping rate $\omega \sim {\gamma }_{\eta }/{\xi }^2$, reflecting the nonequilibrium properties of the near-critical liquid.

    hep-phcond-mat.stat-mechhep-thnucl-ex+1PRD(2026)·4 citations
20. 20*

    Lepton mass textures from non-invertible multiplication rules

    Tatsuo Kobayashi🇯🇵 · Hajime Otsuka🇯🇵 · Morimitsu Tanimoto🇯🇵 · Haruki Uchida🇯🇵

    We study the lepton mass textures, which are derived by ${\mathbb{Z}}_2$ gauging of ${\mathbb{Z}}_M$ symmetries. We can obtain various textures for the Yukawa couplings in the charged lepton sector, but the patterns of neutrino mass matrices are limited. All the obtained textures can not be realized by group-theoretical symmetries, and certain textures can lead to realistic results.

    hep-phJHEP(2025)·35 citations
21. 21*

    Dark photon in parity-violating electron scatterings

    A. W. Thomas🇦🇺 · X. G. Wang🇦🇺 · A. G. Williams🇦🇺

    We proposed that parity-violating electron scattering (PVES) offers a powerful tool to probe the hypothetical dark photon. We calculated the dark photon contributions to PVES asymmetries in both elastic and deep-inelastic scattering (DIS). These contributions are characterised by the corrections to the standard model couplings $C_{1q},C_{2q}$, and $C_{3q}$. At low scales, the corrections to $C_{1q}$ and $C_{3q}$ could be as large as $5\%$ were a dark photon to exist. In DIS at very high $Q^2$, of relevance to HERA or the EIC, the dark photon could induce substantial corrections to $C_{2q}$, suggesting as large as $10\%$ uncertainties in the extraction of valence parton distribution functions. We also extracted the favoured regions of the dark photon parameter space by fitting the parity violation data and the CDF $W$ boson mass, which prefer a heavy dark photon with mass above the $Z$-boson mass.

    hep-phhep-exPoS(2025)·2 citations
22. 22*

    Lepton Number Violation Higgs Decay at Muon Collider

    Fa-Xin Yang🇨🇳 · Feng-Lan Shao🇨🇳 · Zhi-Long Han🇨🇳 · Fei Huang🇨🇳 · Yi Jin🇨🇳 · Honglei Li🇨🇳

    In this paper, we consider the scalar singlet extension of type-I seesaw, where a scalar singlet $S$ and heavy neutral lepton $N$ are further introduced. The Majorana mass term of heavy neutral lepton is generated through the Yukawa interaction with the scalar singlet, which then induces the lepton number violation decays of SM Higgs $h$ and heavy Higgs $H$ via mixing of scalars. As a pathway to probe the origin of heavy neutral lepton mass, we investigate the lepton number violation Higgs decay signature at the TeV-scale muon collider. The dominant production channel of Higgs bosons at the TeV-scale muon collider is via vector boson fusion. So we perform a detailed analysis of the signal process ${\mu }^{+}{\mu }^{-}\to {\nu }_{\mu }{\bar{\nu }}_{\mu }h/H\to {\nu }_{\mu }{\bar{\nu }}_{\mu }NN$ followed by $N\to {\mu }^{\pm }jj$, where the two jets from $W$ boson decay are treated as one fat-jet $J$. With an integrated luminosity of $1(10){\text{ab}}^{-1}$, the 3 (10) TeV muon collider could discover the lepton number violation SM Higgs decay $h\to {\mu }^{\pm }{\mu }^{\pm }JJ$ signature for the Higgs mixing parameter $\sin \alpha >0.05(0.009)$. Meanwhile, a large parameter space can be detected by the lepton number violation heavy Higgs decay $H\to {\mu }^{\pm }{\mu }^{\pm }JJ$ signature for $m_H\lesssim 1(3)$ TeV and $\sin \alpha \gtrsim 0.03(0.005)$ at the 3 (10) TeV muon collider. Therefore, the lepton number violation SM and heavy Higgs decay signatures are both promising at the TeV scale muon collider.

    hep-phhep-exJHEP(2025)·6 citations
23. 23*

    Parton helicities at arbitrary x and Q2 in double-logarithmic approximation

    B.I. Ermolaev🇷🇺

    Description of spin-dependent hadronic processes at high energies in terms of parton helicities is a both effective and technically convenient means. In the present paper, we obtain explicit expressions for the parton helicities when either Collinear or KT forms of QCD Factorization are used. Starting our studies with calculation of the helicities in the double-logarithmic approximation (DLA) in the region of small x and large Q^2, we generalize the results in order to obtain formulae valid at arbitrary x and Q^2. We argue against using Collinear Factorization, when the parton orbital angular momenta are accounted for, and prove that KT Factorization should be used instead. We also consider in detail the small-x asymptotics of the parton helicities, compare them with the DGLAP-asymptotics in LO,NLO, etc and prove that the DGLAP asymptotics are less singular at small x than the Regge asymptotics

    hep-phhep-exEPJC(2026)·4 citations
24. 24*

    Investigating sub-MeV dark matter annihilation to neutrinos using direct detection experiments

    Boris Betancourt Kamenetskaia🇩🇪 · Jong-Chul Park🇰🇷 · Merlin Reichard🇩🇪 · Gaurav Tomar🇮🇳

    Dark matter (DM) could self-annihilate into neutrinos in dense regions of the Universe. We consider the resulting flux of neutrinos from the Milky Way DM halo and derive exclusion limits on the annihilation cross-section using XENONnT electron recoil data. Assuming a $J$-factor independent of the annihilation cross-section, we find leading limits for DM masses below $\mathcal{O}$(MeV). Self-annihilating DM affects the DM halo via dissolution, introducing a cross-section dependency on the halo profile and thus the $J$-factor. We discuss such a situation in more detail, finding that the signal rate is below the experimental sensitivity of XENONnT, leaving the annihilation cross-section unconstrained.

    hep-phhep-exPRD(2025)·3 citations
25. 25*

    Predictions for Identified Hadron (${\pi }^{\pm }$, $K^{\pm }$ and $p(\overline{p})$) Production and Collective Dynamics in Oxygen-Oxygen Collisions at $\sqrt{s_{NN}}$= 7 TeV with EPOS4, AMPT-SM, and Angantyr in Pythia 8

    Rabia Bashir🇵🇰 · Ramoona Shehzadi🇵🇰 · M. U. Ashraf🇺🇸 · A. M. Khan🇺🇸

    We study the dynamics of identified hadrons (${\pi }^{\pm }$, $K^{\pm }$ and $p(\overline{p})$) production in $O+O$ collisions at $\sqrt{s_{\mathrm{NN}}}=7$TeV using recently updated version of EPOS4, string melting version of A Multi-Phase Transport Model (AMPT-SM) and Angantyr model, incorporated within Pythia 8. We examine the interplay between different mechanisms implemented in these models. Predictions for charged particle multiplicity ($d{N}_{ch}/d\eta$), transverse momentum ($p_T$) spectra of identified hadrons, particle yield ($dN/dy$) and mean transverse mass ($⟨m_T⟩$) are presented. To probe the collective behavior of the produced particles, the $p_T$-differential kaons-to-pion and proton-to-pion ratios are studied. While AMPT incorporates some flow effects, EPOS4's implementation of full hydrodynamic flow proves significantly more effective. In contrast, the flow effects in Pythia 8 are substantially weaker compared to the other models. The upcoming $O+O$ data from the LHC will help constrain the parameters of these models.

    hep-phEur.Phys.J.Plus(2025)·3 citations
26. 26*

    Higgs Inflation with Vector-Like Quark Stabilisation and the ACT spectral index

    John McDonald🇬🇧

    Recently, the Atacama Cosmology Telescope (ACT) collaboration has reported a scalar spectral index $n_s=0.9743\pm 0.0034$. This is substantially larger than the classical prediction of Higgs Inflation, $n_s\approx 0.965$, which is 2.74$\sigma$ below the ACT mean value. We show that when an otherwise metastable Standard Model Higgs Inflation potential is stabilised by the addition of vector-like quark pairs and the potential is renormalised in the Jordan frame, the value of $n_s$ is generally larger than 0.965 and can explain the ACT observation. As an example, assuming the 2022 PDG direct measurement central value for the t quark mass, $m_t=172.69$ GeV, and central values for the SM inputs to the renormalisation group equations, we obtain $n_s=0.9792-0.9844$ for the case of three isosinglet vector-like B quarks with mass $m_Q$ in the range 1-3 TeV, with the lowest value of the $n_s$ range being 1.44$\sigma$ above the ACT mean value. The model predicts primordial gravitational wave with tensor-to-scalar ratio $r=7.87\times 10^{-3}-1.21\times 10^{-2}$ for $m_Q=$ 1-3 TeV, which will be easily observable in forthcoming CMB experiments. Observation of vector-like quarks of mass close to 1 TeV mass combined with a large tensor-to-scalar ratio $r\sim 0.01$ would support the model.

    hep-phastro-ph.COJCAP(2026)·19 citations
27. 27*

    Estimates of the masses of heavy right-handed neutrino particles using the seesaw mechanism

    V. V. Khruschov🇷🇺 · S. V. Fomichev🇷🇺

    The mass estimates of active and sterile (right-handed) neutrinos are considered at the phenomenological level using the seesaw mechanism. It is assumed that the neutrino mass values depend on three characteristic scales, and the sum of the active neutrino mass values is limited from above by 0.06 eV. The neutrino mass values are estimated, as well as the observable neutrino mass values, namely, the average mass m_C of active neutrinos and the kinematic neutrino mass m_{\beta} of beta-decay.

    hep-ph1 citation
28. 28*

    Towards a test of the Born rule in high-energy collisions

    Antony Valentini🇬🇧 · Mira Varma🇺🇸

    We consider how the Born rule, a fundamental principle of quantum mechanics, can be tested for particles created on the shortest timescales ($\sim 10^{-25}\mathrm{s}$) currently accessible at high-energy colliders. We focus on targeted tests of the Born rule for spin or polarisation probabilities, which offer a particularly clean experimental signal, and which can be described by a simple hidden-variables model of two-state systems proposed by Bell. These probabilities test a remarkable feature of the quantum formalism, whereby expectation values for incompatible experiments are linearly related. Born-rule violations can be parameterised by nonlinear expectation values for quantum measurements of spin or polarisation, together with anomalies in ensemble averages, which may then be constrained by experiment. Notable experiments considered here include the recent detection of single photons from top-quark decay, and the indirect measurement of tau-lepton polarisation. Repurposing these experiments as tests of the Born rule, however, presents several challenges, which are discussed in this paper.

    hep-phhep-thquant-phPRD(2025)·2 citations
29. 29*

    Primordial Black Holes and Gravitational Waves in Extensions of the Standard Model

    Indra Kumar Banerjee🇮🇳 · Ujjal Kumar Dey🇮🇳 · Shaaban Khalil🇪🇬

    We investigate the phenomenology of a Standard Model extension incorporating an inert scalar doublet and a gauged $U(1{)}_{B-L}$ symmetry. Our analysis reveals regions of the parameter space that support strong first-order phase transitions, including cases featuring two successive transitions. Each transition can generate a stochastic gravitational wave background within the sensitivity reach of upcoming experiments. Remarkably, the high-scale transition may also produce primordial black holes with appreciable abundance.

    hep-phPoS(2025)·0 citations
30. 30*

    A Likelihood Ratio Framework for Highly Motivated Subdominant Signals

    S. Ansarifard🇮🇷

    In particle physics and cosmology, distinguishing subtle new physics signals from established backgrounds is a fundamental and persistent challenge for phenomenologists. This paper discuss a simple and robust statistical framework to evaluate the compatibility of highly motivated (HM) theoretical models with the residuals of experimental results, focusing on scenarios where the data appear consistent with background predictions. A likelihood ratio test is developed that compares null and alternative hypotheses, emphasizing cases where new physics introduces small deviations from the background. The practicality of the framework is highlighted, and in addition to its limitations, strategies to simplify complex background modeling are discussed.

    hep-phastro-ph.CO1 citation
31. 31*

    Dark Matter in Multi-Singlet Extensions of the Standard Model

    Maria Gonçalves🇵🇹 · Margarete Mühlleitner🇩🇪 · Rui Santos🇵🇹 · Tomás Trindade🇵🇹

    We study the simplest extensions of the Standard Model (SM) that provide Dark Matter (DM) candidates, built with the addition of real singlets and new ${\mathcal{Z}}_2$ symmetries. In this type of models the interactions between SM particles are not altered except for the new interactions stemming from the portal couplings that link the SM Higgs with the DM candidates. In the extension with just one singlet, DM masses below about 3.5 TeV are already excluded by the combination of relic density and direct detection (DD) constraints, except in the resonant case where the DM mass is close to half the Higgs mass, making them undetectable at the LHC. Adding just one more real singlet with an independent ${\mathcal{Z}}_2$ symmetry opens up a new mass window for one of the DM candidates and decreases the lower bound on the mass of the other. Adding more singlets with independent ${\mathcal{Z}}_2$ symmetries will not change this picture dramatically. If instead we add new singlets all odd under the same ${\mathcal{Z}}_2$ symmetry, the allowed mass region for the DM candidate (i.e., the lightest dark sector scalar) will span the entire mass range from half the Higgs mass to the TeV scale. In principle, such light particles could be probed at the LHC in mono-$X$ searches. Although they are still out of reach with the current LHC DM searches, there are good chances to probe the models in some final states at the High-Luminosity (HL-LHC) stage of the LHC.

    hep-phJHEP(2026)·9 citations
32. 32*

    Tagging fully hadronic exotic decays of the vectorlike $\mathbf{B}$ quark using a graph neural network

    Jai Bardhan🇮🇳 · Tanumoy Mandal🇮🇳 · Subhadip Mitra🇮🇳 · Cyrin Neeraj🇮🇳 · Mihir Rawat🇮🇳

    Following up on our earlier study in [J. Bardhan et al., Machine learning-enhanced search for a vectorlike singlet B quark decaying to a singlet scalar or pseudoscalar, Phys. Rev. D 107 (2023) 115001; arXiv:2212.02442], we investigate the LHC prospects of pair-produced vectorlike $B$ quarks decaying exotically to a new gauge-singlet (pseudo)scalar field $\Phi$ and a $b$ quark. After the electroweak symmetry breaking, the $\Phi$ decays predominantly to $gg/bb$ final states, leading to a fully hadronic $2b+4j$ or $6b$ signature. Because of the large Standard Model background and the lack of leptonic handles, it is a difficult channel to probe. To overcome the challenge, we employ a hybrid deep learning model containing a graph neural network followed by a deep neural network. We estimate that such a state-of-the-art deep learning analysis pipeline can lead to a performance comparable to that in the semi-leptonic mode, taking the discovery (exclusion) reach up to about $M_B=1.8(2.4)$ TeV at HL-LHC when $B$ decays fully exotically, i.e., BR$(B\to b\Phi )=100\%$.

    hep-phcs.LGhep-exPRD(2025)·2 citations
33. 33*

    Exploring Potential Higgs Resonances at 650 GeV and 95 GeV in the 2HDM Type III

    Rachid Benbrik🇲🇦 · Mohammed Boukidi🇲🇦 · Khouloud Kahime🇲🇦 · Stefano Moretti🇬🇧 · Larbi Rahili🇲🇦 · Bassim Taki🇲🇦

    Recent searches by the CMS collaboration at the Large Hadron Collider (LHC) in the `diphoton plus $b\bar{b}$ final state' have revealed an excess near 650 GeV, which might indicate the presence of a (broad) heavy resonance decaying into a Standard Model (SM) Higgs boson and an additional particle. At the same time, both ATLAS and CMS as well as all experiments at the Large Electron-Position (LEP) collider have reported excesses consistent with a light Higgs boson channel around 95 GeV, suggesting a potential connection between these two signals. In this study, we investigate these anomalies within the context of the CP-conserving 2-Higgs-Doublet Model (2HDM) Type~III. In our proposed scenario, a heavy CP-odd Higgs boson $A$ with a mass near 650 GeV decays into a SM-like Higgs boson $H$ and a $Z$ boson, with the $H$ boson subsequently decaying into diphotons and the $Z$ boson decaying into $b\bar{b}$ pairs. To explain the excess around 95 GeV, we independently select the mass of the light CP-even Higgs boson of the model $h$ to be around this value. This configuration allows for a consistent explanation of both the high- and low-mass excesses observed in the experiments. Through a detailed analysis, we demonstrate that these two signals can be fitted simultaneously at the 2.5$\sigma$ significance level, offering a promising solution to the observed anomalies and potentially hinting at new physics Beyond the Standard Model (BSM).

    hep-phPLB(2025)·12 citations
34. 34*

    A Superalgebra Within: representations of lightest standard model particles form a ${\mathbb{Z}}_2^5$-graded algebra

    N. Furey🇩🇪

    It is demonstrated how a set of particle representations, familiar from the Standard Model, collectively form a superalgebra. Those representations mirroring the internal behaviour of the Standard Model's gauge bosons, and three generations of fermions, are each included in this algebra, with exception only to those irreps involving the top quark. This superalgebra is isomorphic to the Euclidean Jordan algebra of $16\times 16$ hermitian matrices, $H_{16}(\mathbb{C}),$ and is generated by division algebras. The division algebraic substructure enables a natural factorization between internal and spacetime symmetries. It also allows for the definition of a ${\mathbb{Z}}_2^5$ grading on the algebra. Those internal symmetries respecting this substructure are found to be $\mathfrak{su}(3{)}_C\oplus \mathfrak{su}(2{)}_L\oplus \mathfrak{u}(1{)}_Y,$ in addition to four iterations of $\mathfrak{u}(1)$. For spatial symmetries, one finds multiple copies of $\mathfrak{so}(3)$. Given its Jordan algebraic foundation, and its apparent non-relativistic character, the model may supply a bridge between particle physics and quantum computing. We close by describing current research directions. These include (1) detailing how this construction fits into the larger picture of Bott Periodic Particle Physics, first introduced in [1], [2], [3], (2) investigating how the origin of these particle representations might be grounded in the unsung algebra $\mathbb{O}\oplus \mathbb{H}\oplus \mathbb{C}\oplus \mathbb{R}$, and (3) proposing how these two directions may merge by reframing the model in terms of the 16$\mathbb{R}$ dimensional sedenion algebra, $\mathbb{S}.$

    hep-phAnnalen Phys.(2025)·4 citations
35. 35*

    Dark Matter Velocity Distributions for Direct Detection: Astrophysical Uncertainties are Smaller Than They Appear

    Dylan Folsom🇺🇸 · Carlos Blanco🇺🇸 · Mariangela Lisanti🇺🇸 · Lina Necib🇺🇸 · Mark Vogelsberger🇺🇸 · Lars Hernquist🇺🇸

    The sensitivity of direct detection experiments depends on the phase-space distribution of dark matter near the Sun, which can be modeled theoretically using cosmological hydrodynamical simulations of Milky Way-like galaxies. However, capturing the halo-to-halo variation in the local dark matter speeds -- a necessary step for quantifying the astrophysical uncertainties that feed into experimental results -- requires a sufficiently large sample of simulated galaxies, which has been a challenge. In this Letter, we quantify this variation with nearly 100 Milky Way-like galaxies from the TNG50 simulation, the largest sample to date at this resolution. Moreover, we introduce a novel phase-space scaling procedure that endows every system with a reference frame that accurately reproduces the local standard-of-rest speed of our Galaxy, providing a principled way of extrapolating the simulation results to real-world data. The ensemble of predicted speed distributions is well characterized by the standard halo model, a Maxwell-Boltzmann distribution truncated at the escape speed, though the individual distributions can deviate from it, especially at high speeds. The dark matter-nucleon cross section limits placed by these speed distributions vary by ~60% about the median. This places the 1-sigma astrophysical uncertainty at or below the level of the systematic uncertainty of current ton-scale detectors, even down to the energy threshold. The predicted uncertainty remains unchanged when subselecting on those TNG50 galaxies with merger histories similar to the Milky Way. Tabulated speed distributions, as well as Maxwell-Boltzmann fits, are provided for use in computing direct detection bounds or projecting sensitivities.

    hep-phastro-ph.COastro-ph.GAPRL(2025)·19 citations
36. 36*

    Constraining anomalous $Wtb$ and related SMEFT couplings using low-energy and electroweak precision observables

    Subhajit Kala🇮🇳 · Lipika Kolay🇮🇳 · Lopamudra Mukherjee🇨🇳 · Soumitra Nandi🇮🇳

    We investigate constraints on couplings of Standard Model effective field theory (SMEFT) operators contributing to $Wtb$ effective vertex at tree level. We study the one-loop level impact of these couplings on the low-energy flavour changing charged and neutral current processes and on the electroweak precision observables. We use the available data on these relevant processes to constrain the associated SMEFT/$Wtb$ couplings. Solving the renormalisation group equations, we connect the SMEFT couplings at different scales and use the bounds at low energy to obtain the relevant bounds at the large scale $\Lambda$. Our findings indicate significantly improved constraints on the couplings compared to existing constraints on $Wtb$ couplings by ATLAS and CMS. Additionally, we predict branching ratios for various top-FCNC processes, which exceed SM expectations by several orders of magnitude but remain within the reach of future colliders. These SMEFT couplings, or anomalous couplings of the effective $Wtb$ vertex, can further constrain different UV-complete and simplified models that generate such interactions at the tree or loop level.

    hep-phhep-exJHEP(2025)·7 citations
37. 37*

    Warm Inflation with Pseudo-scalar Couplings

    Edward Broadberry🇺🇸 · Anson Hook🇺🇸 · Sagnik Mondal🇺🇸

    Inflaton couplings during warm inflation result in the production of a thermal bath. Thermal friction and fluctuations can dominate the standard de Sitter analogues, resulting in a modified slow-roll scenario with a new source of density fluctuations. Due to issues with back-reaction, it is advantageous to consider inflaton couplings with the thermal bath that are pseudo-scalar in nature, e.g., derivative interactions or topological $F\tilde{F}$ couplings. We demonstrate that {\it every single} existing model of warm inflation utilizing pseudo-scalar couplings needs to be corrected to properly account for all of the chemical potentials that the thermal bath acquires in response to the inflaton coupling. These chemical potentials are for non-conserved charges, and are non-zero only because of the applied inflaton couplings. The model-dependent chemical potentials modify the fluctuation-dissipation theorem, making the relationship between the thermal friction and thermal fluctuations model-dependent. In extreme cases, these chemical potentials can cause the friction term to vanish while thermal fluctuations remain non-zero. In the context of a simple example, we demonstrate how to calculate the chemical potentials, thermal friction, and thermal fluctuations using both the Boltzmann equations and by calculating thermal expectation values, showing explicitly that the two approaches give the same result.

    hep-phastro-ph.COhep-thJHEP(2026)·9 citations
38. 38*

    Interplay between Electroweak Symmetry Breaking and Higgs Portal Dark Matter

    Sreemanti Chakraborti🇬🇧 · André Milagre🇵🇹 · Rui Santos🇵🇹 · João P. Silva🇵🇹

    Models of Dark Matter must contend with the fact that the presence of electroweak symmetry breaking along the thermal evolution of the Universe modifies the masses, interactions and, thus, the thermally averaged cross sections. We study in detail the impact of taking (not taking) the presence of the electroweak symmetry breaking into account in the calculations of the Dark Matter relic density in Higgs portal models, providing a model-independent measure of such differences. By focusing on a particular model, we show that ignoring this effect can lead to the inclusion (exclusion) of wrong (viable) regions of parameter space.

    hep-ph1 citation
39. 39*

    Asteroseismological constraints on--and hints of--dark matter interactions

    Stephanie Beram🇨🇦 · Aaron C. Vincent🇨🇦

    If dark matter interacts with nuclei or electrons, then elastic collisions with constituents of stars will cause some of the galactic dark matter to fall below the escape velocity and become gravitationally bound. For asymmetric dark matter (which does not self-annihilate), the large accumulated population of dark matter can act as an additional source of heat transport, altering stellar structure and evolution. These effects can be probed by the use of asteroseismology. Here, we demonstrate this effect via numerical simulations. We use Monte Carlo-calibrated heat transport calculations, with a focus on the erasure of the convective core in stars that are slightly more massive than the Sun. We find limits on spin-dependent dark matter-nucleon and dark matter-electron interactions using asteroseismological data from a nearby sub-giant star. More tantalizingly, we find a $\gtrsim 4\sigma$ preference for dark matter-electron interactions for dark matter masses $\lesssim 3.5$ GeV and cross sections ${\sigma }_{\chi -e}\sim 10^{-34.5}$ cm${}^2$, albeit in strong tension with limits from Earth-based direct detection experiments.

    hep-phastro-ph.COastro-ph.SR1 citation
40. 40*

    Dynamical Up-quark Mass Generation in QCD-like theories

    Csaba Csáki🇺🇸 · Tuhin S. Roy🇮🇳 · Maximilian Ruhdorfer🇺🇸 · Taewook Youn🇺🇸

    We calculate the dynamically generated up quark mass in some QCD-like theories with $F=3$ light flavors, obtained from supersymmetric QCD perturbed via anomaly mediated supersymmetry breaking. We match the low-energy effective theory to the traditional chiral Lagrangian of QCD and determine the coefficients to next-to-leading order in chiral perturbation theory, while also varying the number of colors $N$. We find that the dynamically generated up quark mass vanishes in the large $N$ limit, and is small for $F<N$, however for $F=N$ there is a sizeable $O(1)$ contribution. While our results are reliable only for small supersymmetry breaking, we observe that extrapolating the $F=N$ result to large supersymmetry breaking would lead to a dynamical up quark mass that is large enough to account for its entire physical mass.

    hep-phnucl-thPRD(2026)·2 citations
41. 41*

    BSM reach of rare charm decays, including the rising star ${\Lambda }_c\to p{\mu }^{+}{\mu }^{-}$

    Hector Gisbert🇪🇸 · Gudrun Hiller🇩🇪 · Dominik Suelmann🇩🇪

    We perform the first global fit of rare charm transitions using recent data on $D^0\to {\mu }^{+}{\mu }^{-}$, $D^{+}\to {\pi }^{+}{\mu }^{+}{\mu }^{-}$, ${\Lambda }_c\to p{\mu }^{+}{\mu }^{-}$ and $D^0\to {\pi }^{+}{\pi }^{-}{\mu }^{+}{\mu }^{-}$ decays, including angular observables. We work out constraints on new physics in the framework of the weak effective field theory. While angular observables in $D^0\to {\pi }^{+}{\pi }^{-}{\mu }^{+}{\mu }^{-}$ decays provide sensitivities to different QCD models, future null tests in ${\Lambda }_c\to p{\mu }^{+}{\mu }^{-}$ look more promising to extract limits because of less hadronic uncertainties. This marks ${\Lambda }_c\to p{\mu }^{+}{\mu }^{-}$ as the rising star of rare charm decays.

    hep-phhep-ex0 citations
42. 42*

    Analysis of Two Models for the Angular Structure of the Outflows Producing the Swift/XRT "Larger-Angle Emission" of Gamma-Ray Bursts

    A. Panaitescu

    The instantaneous emission from a relativistic surface endowed with a Lorentz factor $\Gamma$ that decreases away from the outflow symmetry axis can naturally explain the three phases observed by Swift/XRT in GRBs and their afterglows (GRB tail, afterglow plateau and post-plateau). We expand the analytical formalism of the "Larger-Angle Emission" model previously developed for "Power-Law" outflows to "n-Exponential" outflows (e.g. exponential with $n=1$ and Gaussian with $n=2$) and compare their abilities to account for the X-ray emission of XRT afterglows. We assume power-law $\Gamma$-dependences of two spectral characteristics (peak-energy and peak intensity) and find that, unlike Power-Law outflows, n-Exponential outflows cannot account for plateaus with a temporal dynamical range larger than 100. To include all information existing in the Swift/XRT measurements of X-ray aferglows (0.3-10 keV unabsorbed flux and effective spectral slope), we calculate 0.3 keV and 10 keV light-curves using a broken power-law emission spectrum of peak-energy and low-and high-energy slopes that are derived from the effective slope measured by XRT. This economical peak-energy determination is found to be consistent with more expensive spectral fits. The angular distributions of the Lorentz factor, comoving frame peak-energy, and peak-intensity ($\Gamma (\theta ),E_p^{\prime }(\theta ),i_p^{\prime }(\theta )$) constrain the (yet-to-be determined) convolution of various features of the production of relativistic jets by solar-mass black-holes and of their propagation through the progenitor/circumburst medium, while the $E_p^{\prime }(\Gamma )$ and $i_p^{\prime }(\Gamma )$ dependences may constrain the GRB dissipation mechanism and the GRB emission process.

    ↳ astro-ph.HEhep-ph0 citations
43. 43*

    Phenomenology of baryon dynamics with directed flow in relativistic heavy-ion collisions

    Tribhuban Parida🇮🇳

    This thesis aims to elucidate the role of initial baryon stopping and its diffusion in heavy-ion collisions (HIC) using hydrodynamic model. In this regard, we have studied the observable-directed flow ($v_1$) of identified hadrons, particularly the $v_1$ of baryons and antibaryons, as well as the splitting observed between them in detail. We propose a new ansatz for the initial baryon distribution. By employing this initial baryon deposition model alongside a tilted energy distribution as inputs to a hybrid framework, we successfully describe the rapidity-odd $v_1$ of identified hadrons, including the elusive baryon-antibaryon splitting of $v_1$ across a wide range of $\sqrt{s_{NN}}$. Our model, incorporating baryon stopping and it's subsequent diffusion within a relativistic hydrodynamic framework and employing a crossover equation of state derived from lattice QCD calculations, establishes a non-critical baryonic baseline. Moreover, we demonstrate that recent STAR measurements of the centrality and system-size dependence of $v_1$ splitting between oppositely charged hadrons-attributed to electromagnetic field effects-are significantly influenced by background contributions from baryon stopping and its diffusion. Furthermore, we show that the rapidity dependence of the splitting of the rapidity-even component of $v_1$ between $p$ and $\bar{p}$ is highly sensitive to the initial baryon deposition scheme. If measured experimentally, this could constraint the rapidity dependence of the initial baryon deposition profile. Moreover, it could offer valuable phenomenological insights into the baryon junction picture and help refine constraints on the baryon diffusion coefficient of the medium. Notably, utilizing this phenomenologically successful baryon deposition model, we present the first estimation of the baryon diffusion coefficient for the strongly interacting QCD matter created in HIC.

    ↳ nucl-thhep-exhep-phnucl-ex4 citations
44. 44*

    Method for high-precision determination of the nucleon axial structure using lattice QCD: Removing $\pi N$-state contamination

    Yasumichi Aoki🇯🇵 · Ken-Ichi Ishikawa🇯🇵 · Yoshinobu Kuramashi🇯🇵 · Shoichi Sasaki🇯🇵 · Kohei Sato🇯🇵 · Eigo Shintani🇯🇵 · Ryutaro Tsuji🇯🇵 · Hiromasa Watanabe🇯🇵 · Takeshi Yamazaki (for the PACS Collaboration)🇯🇵

    We performed a precise calculation of physical quantities related to the axial structure of the nucleon using 2+1 flavor lattice QCD gauge configuration (PACS10 configuration) generated at the physical point with lattice volume larger than $(10\mathrm{fm}{)}^4$ by the PACS Collaboration. The nucleon matrix element of the axial-vector current has two types of the nucleon form factors, the axial-vector ($F_A$) form factor and the induced pseudoscalar ($F_P$) form factor. Recently lattice QCD simulations have succeeded in reproducing the experimental value of the axial-vector coupling, $g_A$, determined from $F_A(q^2)$ at zero momentum transfer $q^2=0$, at a percent level of statistical accuracy. However, the $F_P$ form factor so far has not reproduced the experimental values well due to strong $\pi N$ excited-state contamination. Therefore, we proposed a simple subtraction method for removing the so-called leading $\pi N$-state contribution, and succeeded in reproducing the values obtained by two experiments of muon capture on the proton and pion electro-production for $F_P(q^2)$. The novel approach can also be applied to the nucleon pseudoscalar matrix element to determine the pseudoscalar ($G_P$) form factor with the help of the axial Ward-Takahashi identity. The resulting form factors, $F_P(q^2)$ and $G_P(q^2)$, are in good agreement with the prediction of the pion-pole dominance model. In the new analysis, the induced pseudoscalar coupling $g_P^{\ast }$ and the pion-nucleon coupling $g_{\pi NN}$ can be evaluated with a few percent accuracy including systematic uncertainties using existing data calculated at two lattice spacings.

    ↳ hep-lathep-phPRD(2025)·11 citations
45. 45*

    Entanglement saturation in quantum electrodynamics scattering processes

    Massimo Blasone🇮🇹 · Silvio De Siena🇮🇹 · Gaetano Lambiase🇮🇹 · Cristina Matrella🇮🇹 · Bruno Micciola🇮🇹

    We investigate the properties of quantum electrodynamics (QED) two-particle scattering processes when an arbitrarily sharp filtering of the outgoing particles in momentum space is performed. We find that these processes are described by dynamical quantum maps, whose structure is such that any initial state is transformed into a maximally entangled state, after an infinite number of iterations of the map. This structural property is exactly realized if all the colliding particles are massive fermions while, when photons are involved, it is verified in a partial way, depending on the process under consideration.

    ↳ quant-phhep-ph10 citations
46. 46*

    Traversable wormholes from a smoothed string fluid in 4D Einstein-Gauss-Bonnet gravity

    C. R. Muniz🇧🇷 · M. S. Cunha🇧🇷 · L. C. N. Santos🇧🇷

    We investigate traversable wormhole solutions in four-dimensional Einstein-Gauss-Bonnet (EGB) gravity sourced by a smoothed string fluid. Originally proposed to model regular black holes, this energy density profile is adapted here to sustain wormhole geometries by allowing for a radially varying equation of state. We obtain zero-tidal-force solutions that satisfy all traversability criteria and remain globally regular. The Gauss-Bonnet (GB) coupling $\alpha$ plays a central role in shaping the throat geometry. We identify a parameter region ($\alpha \ge 1$, $\epsilon \le 0.1$) in which the null energy condition is satisfied in the vicinity of the throat, representing a significant improvement over general relativistic counterparts. The interplay between the smoothing scale $a$ and the string density $\epsilon$ ensures finite curvature invariants while reducing the violation of energy conditions. An analysis of the volume integral quantifier and the complexity factor further shows that strong EGB coupling simultaneously suppresses gravitational complexity and the total amount of exotic matter. These results establish a unified framework in which the same string fluid source can generate both regular black holes and stable traversable wormholes, depending on the strength of higher-curvature corrections.

    ↳ gr-qchep-phhep-thAnnals Phys.(2026)·3 citations
47. 47*

    Quarkyonic picture of isospin QCD

    Oleksii Ivanytskyi🇵🇱

    We suggest a new look onto the thermodynamics of cold isospin QCD matter described within the quarkyonic framework, when confining forces are essential only for the momentum states close to the Fermi sphere and lead to formation of the quark-antiquark correlations with quantum numbers of pions. Within this picture cold isospin QCD matter is constituted by the Bose-Einstein condensate of pions and free (anti)quarks. We develop a simple confining model of pions existing as the lowest energy $P$-state of in-medium three-dimensional harmonic oscillator and use it to show that under the conditions of isospin QCD quarkyonic matter can onset at densities significantly smaller than the overlap density of pions. Using the experimentally established pion charge radius we demonstrate that the onset density can be even lower than two nuclear saturation densities. To analyze the lattice QCD data we develop a field-theory inspired model of quark-antiquark-pion matter with vector-isovector repulsion among pions and (anti)quarks. The quark substructure of pions, which is one of the key elements of the model, is accounted for within the one-loop no-sea approximation and leads to an effective medium dependence of the pion mass. The latter is shown to be crucial for providing asymptotic vanishing of the pion density and pion condensate, which reflects pion dissociation due to asymptotic freedom of QCD. The proposed quarkyonic picture of isospin QCD agrees with the results of perturbative calculations on reaching the conformal limit of QCD and with the data of lattice simulations, which supports its viability and physical relevance.

    ↳ nucl-thhep-phhep-thPRD(2025)·13 citations
48. 48*

    Estimating the Lensing Probability for Binary Black Hole Mergers in AGN disk by Using Mismatch Threshold

    Wen-Long Xu🇨🇳 · Yu-Zhe Li🇺🇸 · Yi-Gu Chen · Hui Li🇨🇳 · Wei-Hua Lei🇨🇳

    Stellar-mass binary black holes (BBH) may form, evolve, and merge within the dense environments of active galactic nuclei (AGN) disks, thereby contributing to the BBH population detected by gravitational wave (GW) observatories. Mergers occurring in AGN disks may be gravitationally lensed by the supermassive black hole at the AGN centre. The probability of such lensing events has been approximately estimated by using the Einstein criterion in previous work. However, a more reasonable approach to calculating the lensing probability should be based on whether the detector can distinguish the lensed GW waveform from the unlensed one. In this work, we calculate the lensing probability of LIGO sources embedded in AGN disk by relating threshold mismatch to the signal-to-noise ratio of the observed events. For the sensitivity of LIGO-Virgo-KAGRA O3 observation runs, our results indicate that the lensing probability is several times higher than previous estimates. If AGNs are indeed the primary formation channel for BBHs, we could quantify the probability of detecting the lensed GW events in such a scenario. The non-detections, on the other hand, will place stricter constraints on the fraction of AGN disk BBHs and even the birthplaces of BBH mergers.

    ↳ astro-ph.HEhep-phPRD(2026)·2 citations
49. 49*

    Violation of NCQ scaling in hadron elliptic flow in Au+Au collisions at $\sqrt{s_{NN}}=3.0-7.7GeV

    Xun Zhu🇨🇳 · Gao-Chan Yong🇨🇳

    We investigate the number-of-constituent-quark (NCQ) scaling of elliptic flow for various hadrons in non-central Au+Au collisions at \(\sqrt{s_{NN}} = 3.0\text{--}7.7\,\mathrm{GeV}\) using the AMPT model with string melting (SM) and pure hadron cascade (HC) modes. For the SM case, NCQ scaling is absent at \(\sqrt{s_{NN}} =3.0\,\mathrm{GeV}\) but is largely restored by \(\sqrt{s_{NN}} =3.9\,\mathrm{GeV}\). Although quark coalescence occurs at \(\sqrt{s_{NN}} =3.0\,\mathrm{GeV}\), the lack of NCQ scaling is attributed to the insufficient development of quark elliptic flow and the limited production of strange quarks and antiquarks. This finding suggests that NCQ scaling could not be considered a definitive signature of quark-gluon plasma (QGP) formation in the RHIC fixed-target energy region. For the HC case, as expected, no NCQ scaling is observed. However, a mass ordering in the elliptic flow emerges at \(\sqrt{s_{NN}} =4.5\,\mathrm{GeV}\), indicating that full thermalization may not be a prerequisite for mass ordering.

    ↳ nucl-thhep-phnucl-exPLB(2025)·4 citations
50. 50*

    Angular momentum of glasma

    Margaret E. Carrington🇨🇦 · Stanislaw Mrowczynski🇵🇱

    The earliest phase of an ultrarelativistic heavy ion collision can be described as a highly populated system of gluons called glasma. We study some glasma characteristics related to the system's angular momentum. The first one is the global angular momentum perpendicular to the reaction plane, which is spanned by the beam axis and impact parameter vector. We show that only a small fraction of the enormous initial angular momentum of the colliding ultrarelativistic nuclei is transferred to the glasma. Our main focus is the glasma angular momentum directed along the beam axis. This quantity has a local character and results from the inhomogeneous velocity field generated in the glasma. We calculate the vorticity and local angular momentum which show noticeably different behaviour. The results are analyzed in detail and discussed in the context of existing experimental data. We argue that neither vorticity nor thermal vorticity but instead the local angular momentum controls the polarization of final-state hadrons.

    ↳ nucl-thhep-phPRC(2026)·5 citations
51. 51*

    Isotropy Test with Quasars Using Method of Smoothed Residuals

    Akhil Antony🇰🇷 · Stephen Appleby · William L Matthewson🇰🇷 · Arman Shafieloo🇰🇷

    To assess the significance and scale dependence of anomalous large scale modes in the CatWISE quasar data, we generate smoothed number density fields on the sphere and study their extreme values -- maximum, minimum, maximum antipodal difference. By comparing these summary statistics to those obtained from random isotropic realisations of the data, we determine the statistical significance of large scale modes as a function of smoothing scale. We perform our analysis using five different versions of the data -- the original quasar map, the maps after separately subtracting the ecliptic bias and the CMB dipole, the map obtained after subtracting both, and the map after subtracting the ecliptic bias and anomalous dipole inferred in \cite{Secrest2021}. We find that the ecliptic-corrected, CMB dipole-removed map exhibits large scale modes that are in tension with random realisations of the data (p-values $p\lesssim 10^{-4}$), over a wide range of smoothing scales $\pi /8\le \delta \le \pi /2$. The most prominent feature in the data is an under-density in the southern galactic plane at $(b,\ell )=(-31^{\circ },78^{\circ })$, which reaches its highest statistical significance when smoothed on scales $\delta =\pi /6$ ($p=1.2\times 10^{-6}$). Notably, the minima statistics align with the maximum antipodal difference statistics, whereas the maxima do not. This suggests that the observed dipole-like behavior in the data is primarily driven by the under-density in the southern sky. The ecliptic corrected, anomalous dipole subtracted map reduces the significance of any residual anisotropic features, but an under-density in the south sky persists with p-value $p=0.0018$.

    ↳ astro-ph.COhep-phJCAP(2026)·2 citations
52. 52*

    Effective Quantum Gravitational Collapse in Metric Variables: The $\bar{\mu }$ Scheme

    L. Boldorini🇮🇹 · G. Montani🇮🇹

    We study, using the metric variables, how an effective theory for the Oppenheimer-Snyder gravitational collapse can be built with the $\bar{\mu }$ scheme from Loop Quantum Gravity (LQG). The collapse is analyzed for both the flat and spherical models. In both scenarios the effective theory make possible to avoid the formation of the singularity. The source of this is found in the presence of a negative pressure term inside the stress-energy tensor of the gravitational field. This pressure is analyzed and is concluded that the effective polymer model is the reason why the negative pressure appears. A characterization of the solutions for both models is also carried out, showing that the collapse is altered and avoided in favor of a transition from a black hole state to a white hole one, transition that occurs when the collapse has reached a Planckian regime.

    ↳ gr-qchep-phquant-ph1 citation
53. 53*

    Dynamics of $E_6$ Chiral Gauge Theories

    Andrew Goh🇺🇸 · Hitoshi Murayama🇺🇸 · Gup Singh🇺🇸 · Bethany Suter🇺🇸 · Jason Wong🇺🇸

    We present exact non-perturbative solutions to chiral gauge theories based on the $E_6$ gauge group and several matter fermions in the fundamental $27$-dimensional representation. They are obtained when supersymmetric versions are perturbed by small supersymmetry breaking by anomaly mediation. The universality classes obtained are very different from what can be conjectured by the tumbling hypothesis. In particular, the case with three $27$s may have an unbroken $\text{SU}(3)$ symmetry with massless composite fermions in $10$ of $\text{SU}(3)$. For this case, we employed numerical techniques to obtain the exact ground state.

    ↳ hep-thhep-phPRD(2025)·7 citations

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