Thu·Apr 17, 2025Thursday·April 17, 2025

1. 01*

   Quasi-particle hydrodynamics with momentum-dependent relaxation time

   Arghya Mukherjee🇮🇳 · Samapan Bhadury🇵🇱 · Pracheta Singha🇷🇴

   We formulate the relativistic dissipative hydrodynamics of a system of quasi-particles from the Boltzmann equation within the ambit of relaxation time approximation with modified collision kernels. We focus on two specific scenarios with single quasi-particle species, (i) the extended relaxation time approximation, and (ii) the novel relaxation time approximation. We find that both approaches lead to equivalent results up to first-order in spacetime gradients. We generalize the extended relaxation time approach to incorporate multiple quasi-particle species and obtain the corresponding expressions for the shear (${\eta }_s$) and bulk (${\zeta }_s$) viscous coefficients. As an application, we study the temperature dependence of the transport coefficients of hot QCD medium with quasi-gluon and (light and strange) quasi-quark sectors considering the power law ansatz for the momentum dependence of the relaxation time. We explore the impact of the power law exponent on the ratio ${\zeta }_s/{\eta }_s$. Our study suggests that in comparison to a constant exponent, a temperature dependent exponent in the power law ansatz is more suitable for modeling the quasi-particle dynamics in the relevant temperature regime of heavy ion collision.

   hep-phnucl-thPRD(2025)·4 citations
2. 02*

   One-loop pseudoscalar mass in a 2HDM with a $Z_3$ symmetry

   P.M. Ferreira🇵🇹 · Tomás F. Pinto🇵🇹

   A two-Higgs doublet model with a discrete $Z_3$ symmetry acquires, in its scalar and gauge sectors, an accidental continuous $U(1)$ symmetry. One therefore finds, after spontaneous symmetry breaking of those symmetries, that a massless pseudoscalar arises, as expected by Goldstone's theorem. In the fermion sector, however, it is possible to obtain Yukawa matrix textures which distinguish between the $Z_3$ and $U(1)$ symmetries, so one expects loop corrections to originate a non-zero pseudoscalar mass for the $Z_3$ case. We perform an explicit calculation that shows that at one-loop the pseudoscalar remains massless for all but one tested $Z_3$ Yukawa matrices. The pseudoscalar mass thus found is highly suppressed by the hierarchy of fermion masses.

   hep-phJHEP(2025)·2 citations
3. 03*

   An Application of Diagrammatic Renormalization to $2^{++}$ Tensor Di-Gluonium

   T. de Oliveira🇨🇦 · Siyuan Li🇨🇦 · T.G. Steele🇨🇦

   We apply the diagrammatic renormalization method to the NLO analysis of the $2^{++}$ tensor di-gluonium channel within the QCD sum-rules approach. Diagrammatic renormalization eliminates non-local divergences directly, avoiding the construction of renormalization factors and complications arising from operator mixing in the conventional renormalization method. The local divergences in QCD correlation functions contribute only to subtraction terms in dispersion relations in QCD sum-rules, making it particularly well-suited for diagrammatic renormalization as the local divergences do not enter sum-rules analysis. We provide a detailed example of renormalizing a representative NLO diagram and perform a comprehensive comparison of all non-zero NLO diagrams for $2^{++}$ tensor di-gluonium treated with both diagrammatic and conventional operator-mixing methods. The results from both approaches are in agreement, confirming the validity of diagrammatic renormalization. By simplifying the renormalization process, the diagrammatic renormalization method offers a practical alternative for higher-loop analysis of gluonium states and extensions to multi-quark systems.

   hep-phInt.J.Mod.Phys.A(2025)·0 citations
4. 04*

   $D^0-{\bar{D}}^0$ mixing in the Dyson-Schwinger approach

   Xiaotong Xie🇨🇳 · Hiroyuki Umeeda🇨🇳 · Jinglong Zhu🇨🇳

   In view of difficulty to reproduce observables in the $D^0-{\bar{D}}^0$ mixing via the operator product expansion, we discuss the Dyson-Schwinger approach to this process. Formulated by the parametrization of quark propagators, SU(3) breaking relevant to charm mixing is evaluated in such a way that properly takes account of dynamical chiral symmetry breaking. The ${\bar{D}}^0\to D^0$ transition is discussed in the vacuum-insertion approximation with locality of the light valence-quark field, represented by the decay constant of $D^0$ meson as well as relevant momentum integrals. It is found that dimensionless mass-difference observable in this approach leads to $|x|=(1.3-2.9)\times 10^{-3}$, the order of magnitude comparable to the HFLAV data, and thereby offering a certain improvement as a theoretical framework.

   hep-phhep-exPRD(2025)·2 citations
5. 05*

   Progress in $\mathcal{C}\mathcal{P}$ violating top-Higgs coupling at the LHC with Machine Learning

   A. Hammad🇯🇵 · Adil Jueid🇰🇷

   A precise measurement of the top-Higgs coupling is essential in particle physics, as it offers a powerful probe of potential new physics beyond the Standard Model (BSM), particularly scenarios involving $\mathcal{C}\mathcal{P}$ violation, which is a key condition in addressing the problem of baryon asymmetry of the universe. In this article, we review the recent progress in the studies of the the top-Higgs coupling at the Large Hadron Collider (LHC). We briefly highlight the recent Machine Learning (ML) algorithms being used and their role in constraining the $\mathcal{C}\mathcal{P}$ phase of the top-Higgs coupling with an emphasis on the future potential of beyond-the-traditional methods such as transformers and heterogeneous graphs in these studies.

   hep-phNPB(2025)·7 citations
6. 06*

   Light WIMPs and MeV Gamma-ray Detection with COSI

   Yu Watanabe🇯🇵 · Shigeki Matsumoto🇯🇵 · Christopher M. Karwin🇺🇸 · Tom Melia🇯🇵 · Michela Negro🇺🇸 · Thomas Siegert🇩🇪 · Yuki Watanabe🇯🇵 · Hiroki Yoneda🇩🇪 · Tadayuki Takahashi🇯🇵

   Light weakly interacting massive particles (WIMPs), whose masses are in the sub-GeV scale, have been attracting more attention due to the negative results searching for traditional WIMPs. The light WIMPs are expected to produce gamma rays from annihilation in the MeV energy region. Advancements in technology have opened up possibilities to precisely detect MeV gamma rays, leading to the upcoming space-based mission of the Compton Spectrometer and Imager (COSI). We comprehensively and quantitatively study the phenomenology of light WIMPs to determine if the COSI observations will probe their viable model parameter regions. We first construct models to describe light WIMPs based on the minimality and renormalizability of quantum field theory. Next, we impose various constraints on the models obtained from cosmological observations (CMB, BBN) and dark matter searches (accelerator, underground, astrophysical experiments, etc.). Finally, we identify viable parameter regions in each model and discuss whether or not COSI will be sensitive to the parameter regions. We find that a velocity-dependent annihilation cross-section is predicted in some regions, enabling COSI to detect the dark matter signal while avoiding severe constraints from cosmological observations.

   hep-phastro-ph.HEJHEP(2025)·11 citations
7. 07*

   Towards a Refined Understanding of Non-holomorphic Soft SUSY-Breaking Effects on the Higgs Boson Mass Spectra

   Muhammad Rehman🇵🇰 · Sven Heinemeyer🇪🇸

   We study the impact of the non-holomorphic (NH) soft supersymmetry-breaking terms $T_{33}^{\prime D}$ and ${\mu }^{\prime }$, which introduce additional SUSY-breaking effects beyond the holomorphic structure of the superpotential, on the Higgs boson mass spectrum in the NH Minimal Supersymmetric Standard Model (NHSSM). The term $T_{33}^{\prime D}$ modifies the scalar bottom-quark mass matrix and Higgs couplings, while ${\mu }^{\prime }$ affects the mass matrices of charginos and neutralinos. In our analysis, we incorporate constraints from charge- and color-breaking (CCB) minima where we find that a portion of the parameter space is excluded by these constraints. Focusing on the allowed parameter space, the NH contributions to the light $\mathcal{C}\mathcal{P}$-even Higgs boson mass, $M_h$, from ${\mu }^{\prime }$ and $T_{33}^{\prime D}$ can reach up to $1.4\mathrm{GeV}$ and $90\mathrm{MeV}$, respectively. For the heavy $\mathcal{C}\mathcal{P}$-even Higgs boson mass, $M_H$, and the charged Higgs boson mass, $M_{H^{\pm }}$, these contributions can be substantially larger in certain regions of the parameter space, reaching up to $44\mathrm{GeV}$ for $M_H$ and $42\mathrm{GeV}$ for $M_{H^{\pm }}$ due to ${\mu }^{\prime }$, and up to $60\mathrm{GeV}$ due to $T_{33}^{\prime D}$ for both $M_H$ and $M_{H^{\pm }}$. These corrections are significantly larger than the expected future experimental precision for Higgs boson masses and should therefore be considered in precision analyses for future experiments.

   hep-phPRD(2025)·4 citations
8. 08*

   Predictions for neutron star mergers from the gauge/gravity duality

   Matti Jarvinen🇰🇷

   The gauge/gravity duality, combined with information from lattice QCD, nuclear theory, and perturbative QCD, can be used to constrain the equation of state of hot and dense QCD. I discuss an approach based on the holographic V-QCD model, which includes both nuclear and quark matter phases, separated by a first order phase transition. By using this model in state-of-the-art simulations of neutron star binaries, I study the formation of quark matter during the merger process, and its effect on the threshold mass for prompt collapse into a black hole.

   hep-phhep-thPoS(2025)·0 citations
9. 09*

   Extended scalar sectors from all angles -- Mostly at lepton colliders

   Tania Robens🇭🇷

   I briefly discuss the current state of the art for models with extended scalar sectors and give examples for corresponding investigations, with a focus on processes at lepton colliders.

   hep-phPoS(2025)·3 citations
10. 10*

    A Light Lepton-flavor-violating Flavon: the Messenger of Neutrino Mixing and Muon $g-2$

    Shuyang Han🇨🇳 · Zhaofeng Kang🇨🇳

    In neutrino physics, a class of models with local or global family symmetries may be invoked, and then a flavon field is needed to realize the full neutrino mixing. This flavon may shed light on the long-standing muon $g-2$ puzzle. In this work, we explore this idea in the $(B-L{)}_{13}$ gauge extension to the standard model (SM), in which realistic neutrino mixing requires both a SM singlet flavon $s$ and a vector-like lepton (VLL) doublet. The dominant coupling between the flavon and leptons is in the manner of lepton-flavor-violation (LFV). Through an analytical analysis of the SM lepton-VLL mixing matrix, we find that the parameter space of the $s\bar{\mu }e$-type flavon to explain the muon $g-2$ has been completely excluded by the specific LFV process, muonium-antimuonium oscillation. But the $s\bar{\mu }\tau$-type flavon still has the opportunity; however, it confronts the strong constraint from $\tau \to \mu$ conservation and, in particular, the lepton flavor universality test of $Z$ boson decay, which arises due to our way to realize the LFV flavon. The surviving flavon is highly predictable, with mass in the narrow window $m_{\tau }\lesssim m_s\lesssim 1.5m_{\tau }$ and LFV coupling strength $\sim 10^{-2}$. Besides, it leaves a TeV scale VLL with a multi-lepton signature at the LHC.

    hep-phPRD(2025)·1 citation
11. 11*

    Heavy neutrino mixing prospects at hadron colliders: a machine learning study

    Si-Yu Chen🇨🇳 · Yu-Peng Jiao🇨🇳 · Shi-Yu Wang🇨🇳 · Qi-Shu Yan🇨🇳 · Hong-Hao Zhang🇨🇳 · Yongchao Zhang🇨🇳

    We apply machine learning to the searches of heavy neutrino mixing in the inverse seesaw in the framework of left-right symmetric model at the high-energy hadron colliders. The Majorana nature of heavy neutrinos can induce the processes $pp\to W_R^{\pm }\to {\ell }_{\alpha }^{\pm }N\to {\ell }_{\alpha }^{\pm }{\ell }_{\beta }^{\mp ,\pm }jj$, with opposite-sign (OS) and same-sign (SS) dilepton and two jets in the final state. The distributions of the charged leptons $\ell =e,\mu$ and jets and their correlations are utilized as input for machine learning analysis. It is found that for both the OS and SS processes, XGBoost can efficiently distinguish signals from the standard model backgrounds. We estimate the sensitivities of heavy neutrino mass $m_N$ and their mixing in the OS and SS $ee$, $\mu \mu$ and $e\mu$ final states at $\sqrt{s}=14$ TeV, 27 TeV and 100 TeV. It turns out that the heavy neutrinos can be probed up to 17.1 TeV and 19.5 TeV in the OS and SS channels, respectively. The sine of the mixing angle of heavy neutrinos can be probed up to the maximal value of $\sqrt{2}/2$ and 0.69 in the OS and SS channels, respectively.

    hep-ph1 citation
12. 12*

    Study on charmonium(-like) mesons within a diabatic approach

    Zi-Zhao Zhang🇨🇳 · Rong Li🇨🇳 · Bo-Chao Liu🇨🇳

    In this work, we study the charmonium(-like) spectrum below 4.1 GeV using the diabatic approach, which offers a unified description of conventional and unconventional heavy meson states. Compared to previous studies, we consider a more realistic $c\bar{c}$ potential with including the spin-dependent interactions, which allows us to obtain more states and get more insights on the charmonium spectrum. Based on our calculation, we obtain the masses of the charmonium spectrum which align with the experimental data well. We also present the probabilities of finding various components, i.e. $c\bar{c}$ or meson-meson pair, in those states. Our results support the arguments that the ${\chi }_{c1}(3872)$, $\psi (4040)$ and ${\chi }_{c2}(3930)$ have significant molecular components. In addition, our calculations show that the ${\chi }_{c0}(3860)$ and $\psi (3770)$ can be looked as the candidates for the charmonium states ${\chi }_{c0}(2P)$ and $\psi (1D)$, respectively.

    hep-phCPC(2025)·1 citation
13. 13*

    Search for additional scalar bosons within the Inert Doublet Model in a final state with two leptons at the FCC-ee

    Anubha Bal🇬🇧 · Edward Curtis🇬🇧 · Anne-Marie Magnan🇬🇧 · Benedikt Maier🇬🇧 · Tania Robens🇭🇷 · Nicholas Wardle🇬🇧

    We present a search for new scalar bosons predicted by the Inert Doublet Model at an $e^{+}{e}^{-}$ machine with centre-of-mass energies of 240 and 365 GeV. Within this model, four additional scalar bosons ($H,A,H^{+}$ and $H^{-}$) are predicted. Due to an additional symmetry, the lightest new scalar, here chosen to be $H$, is stable and provides an adequate dark matter candidate. The search for pair production of the new scalars is investigated in final states with two electrons or two muons, in the context of the future circular collider proposal, FCC-ee. Building on previous studies in the context of the CLIC proposal, this analysis extends the search to detector-level objects, using a parametric neural network to enhance the signal contributions over the Standard Model backgrounds, and sets projected exclusion and discovery contours in the $M_A-M_H$ vs. $M_H$ plane. With a total integrated luminosity of 10.8 (2.7) ab${}^{-1}$ for $\sqrt{s}=240$ (365) GeV, the discovery reach for the model goes up to $m_H=108$ (157) GeV for $M_A-M_H=15$ GeV. For exclusion, almost the entire phase-space available in the $M_A-M_H$ vs. $M_H$ plane is expected to be ruled out at 95\% CL, reaching up to $M_H=110$ (165) GeV.

    hep-phhep-exEPJC(2025)·7 citations
14. 14*

    How Accidental was Inflation?

    Ignatios Antoniadis🇹🇭 · John Ellis🇬🇧 · Wenqi Ke🇺🇸 · Dimitri V. Nanopoulos🇺🇸 · Keith A. Olive🇺🇸

    Data on the cosmic microwave background (CMB) are discriminating between different models of inflation, disfavoring simple monomial potentials whilst being consistent with models whose predictions resemble those of the Starobinsky $R+R^2$ cosmological model. However, this model may suffer from theoretical problems, since it requires a large initial field value, threatening the validity of the effective field theory. This is quantified by the Swampland Distance Conjecture, which predicts the appearance of a tower of light states associated with an effective ultra-violet cutoff. This could be lower than the inflation scale for cases with an extended period of inflation, leading to an additional problem of initial conditions. No-scale supergravity models can reproduce the predictions of the Starobinsky model and accommodate the CMB data at the expense of fine-tuning of parameters at the level of $10^{-5}$. Here, we propose a solution to this problem based on an explicit realisation of the Starobinsky model in string theory, where this `deformation' parameter is calculable and takes a value of order of the one corresponding to the Starobinsky inflaton potential. Within this range, there are parameter values that accommodate more easily the combination of Planck, ACT and DESI BAO data, while also restricting the range of possible inflaton field values, thereby avoiding the swampland problem and predicting that the initial conditions for inflation compatible with the CMB data are generic.

    hep-phastro-ph.COgr-qchep-thJCAP(2025)·43 citations
15. 15*

    dSphobic Dark Matter

    Asher Berlin🇺🇸 · Joshua W. Foster🇺🇸 · Dan Hooper🇺🇸 · Gordan Krnjaic🇺🇸

    We present a mechanism that allows thermal relic dark matter to annihilate efficiently in the Galactic Halo and in galaxy clusters, but not in the lower-velocity environments of dwarf spheroidal (dSph) galaxies. We realize this within a complete model in which the dark matter consists of two distinct states separated by a small mass splitting. An indirect detection signal is generated only through the coannihilations of these two states, requiring both to be present. In the halo of the Milky Way, the dark matter particles in the lighter state can be excited into the long-lived heavier state through scattering. Once excited, these heavier particles can coannihilate with those in the lighter state, yielding a gamma-ray signal with little or no suppression. By contrast, the dark matter particles in dwarf galaxies do not possess enough kinetic energy to be excited, thereby suppressing the coannihilation rate and corresponding indirect detection signals from those systems. This framework breaks the predictive relationship that ordinarily exists between these respective gamma-ray signals and complicates our ability to interpret the results of indirect detection searches.

    hep-phastro-ph.COJCAP(2026)·8 citations
16. 16*

    Search for Axions in Magnetic White Dwarf Polarization at Lick and Keck Observatories

    Joshua N. Benabou🇺🇸 · Christopher Dessert🇺🇸 · Kishore C. Patra🇺🇸 · Thomas G. Brink🇺🇸 · WeiKang Zheng🇺🇸 · Alexei V. Filippenko🇺🇸 · Benjamin R. Safdi🇺🇸

    We present the most sensitive search to date for light axion-like particles with masses below a micro-eV, using spectropolarimetric data collected from the Lick and Keck Observatories. The conversion of optical photons emitted from the surface of a magnetic white dwarf (MWD) into axions in the strong magnetic field around the star induces a nearly wavelength-independent linear polarization in the observed starlight. We analyze the Stokes parameters $(U,Q,I)$ measured with the Kast spectrograph at the Lick Observatory toward the MWDs SDSS J033320+000720 and ZTF J190132+145807, and with the LRISp-ADC instrument at the Keck Observatory toward ZTF J190132+145807, SDSS J002129+150223, and SDSS J100356+053825 to search for this effect. The data show no evidence of axion-induced linear polarization, and we set world-leading constraints on the axion-photon coupling $|g_{a\gamma \gamma }|\lesssim 1.7\times 10^{-12}{\mathrm{GeV}}^{-1}$ at the $95\%$ confidence level for masses $m_a\lesssim 2\times 10^{-7}\mathrm{eV}$.

    hep-phastro-ph.HEastro-ph.SR30 citations
17. 17*

    Factorization for Collider Dataspace Correlators

    Andrew J. Larkoski🇺🇸

    A metric on the space of collider physics data enables analysis of its geometrical properties, like dimensionality or curvature, as well as quantifying the density with which a finite, discrete ensemble of data samples the space. We provide the first systematically-improvable precision calculations on this dataspace, presenting predictions resummed to next-to-leading logarithmic accuracy, using the Spectral Energy Mover's Distance (SEMD) as its metric. This is accomplished by demonstration of factorization of soft and collinear contributions to the metric at leading power and renormalization group evolution of the single-scale functions that are present in the factorization theorem. As applications of this general framework, we calculate the two-point correlator between pairs of jets on the dataspace, and the measure of the non-Gaussian fluctuations in a finite dataset. For the non-Gaussianities, our calculations validate the existence of a universal structure that had been previously observed in simulated data. As byproducts of this analysis, we also calculate the two-loop anomalous dimension of the SEMD metric and show that the original Energy Mover's Distance metric is identical to the SEMD through next-to-next-to-leading logarithmic accuracy.

    hep-phhep-exPRD(2025)·2 citations
18. 18*

    Tests of quantum contextuality in particle physics

    M. Fabbrichesi🇮🇹 · R. Floreanini🇮🇹 · E. Gabrielli🇮🇹 · L. Marzola🇪🇪

    Quantum contextuality refers to the impossibility of assigning a predefined, intrinsic value to a physical property of a system independently of the context in which the property is measured. It is, perhaps, the most fundamental feature of quantum mechanics. The many states with different spin that particle physics provides are the ideal setting for testing contextuality. We verify that the polarization states of single spin-1 massive particles produced at colliders are contextual. We test $W^{+}$ gauge bosons produced in top-quark decays, $J/\psi$ and $K^{\ast }(892{)}^0$ mesons in $B$-meson decays and $\varphi$ mesons in ${\chi }_c^0$ and ${\chi }_c^1$ charmonium decays by reinterpreting the data and the analyses of the ATLAS, LHCb, Belle II and BESIII experimental collaborations, respectively. The polarization states of these four particles show contextuality with a significance larger than $5\sigma$. We also discuss the presence of quantum contextuality in spin states of bipartite systems formed by spin-1/2 particles. We test $\Lambda$ and $\Sigma$ baryons reinterpreting two BESIII data analyses, and pairs of top quarks utilizing a recent analysis of the CMS collaboration. Quantum contextuality is present with a significance exceeding $5\sigma$ also in these cases. In addition, we study the feasibility of testing quantum contextuality by means of $Z$ boson production in association with the Higgs boson, $Z$ and $W$ bosons pairs created in Higgs boson decays and with pairs of $\tau$ leptons. For the latter, we use Monte Carlo simulations that mimic the settings of SuperKEKB and of future lepton colliders. Experiments at high energies, though not designed for the purpose, perform surprisingly well in testing for quantum contextuality.

    hep-phhep-exquant-phPRD(2025)·10 citations
19. 19*

    Natural complex plane for kaon CKM data: framework, status and future

    Avital Dery🇨🇭

    Kaon physics can be used to independently determine three out of the four parameters of the CKM matrix, without any B physics input. Treating one parameter, $|V_{us}|$, or alternatively Wolfenstein $\lambda$, as well known, we show that the natural plane for the presentation of kaon CKM information is spanned by the combinations $\left(A^2(1-\hat{\rho }),A^2\hat{\eta }\right)$. In this way, the use of B physics inputs is avoided, as well as the artificial inflation of errors due to parametric uncertainties, mainly due to $|V_{cb}|$. We show that the current status of kaon CKM constraints, impacted by recent advances in measurement and theory, is characterized by four allowed regions, and find that incoming data will inevitably disfavor a number of them, either confirming the CKM paradigm as dominant, or discovering a departure from the Standard Model.

    hep-phhep-exPRD(2025)·7 citations
20. 20*

    Gravitational wave signatures of non-singular matter bouncing cosmology in NANOGrav and beyond

    Theodoros Papanikolaou🇮🇹

    Non-singular matter bouncing cosmological setups are of particular interest since apart from adressing the initial singularity problem they can give rise as well to a nearly scale-invariant curvature power spectrum on scales $k<10^4{\mathrm{Mpc}}^{-1}$, favored by Cosmic Microwave Background (CMB) experiments. Interestingly enough, one can find that within such non-singular bouncing cosmological setups, curvature perturbations grow on super-horizon scales during the matter contracting phase. In this work, we account for the evolution of cosmological perturbations during the transition to the Hot Big Bang expanding Universe, finding at the end naturally enhanced curvature perturbations on very small scales at horizon-crossing time during the expanding phase. These enhanced cosmological perturbations can induce gravitational waves (GWs) due to second order gravitational interactions and collapse as well to form primordial black holes (PBHs), with the latter acting as one of the most viable dark matter candidates. Remarkably, we find an induced GW background with a universal infrared (IR) frequency scaling of $f^2$, in excellent agreement with the recently released $\mathrm{nHz}$ GW data by the NANOGrav collaboration, being potentially detectable as well by other GW observatories such as LISA and ET, depending on the values of the bouncing cosmological parameters at hand.

    ↳ gr-qcastro-ph.COhep-phPoS(2025)·0 citations
21. 21*

    Low-energy neutrino responses for 71Ga by electron capture rates, charge exchange reactions and shell model calculations

    Yoritaka Iwata🇯🇵 · Hiroyasu Ejiri🇯🇵 · Shahariar Sarkar🇮🇳

    Weak Gamow-Teller (GT) responses for low-lying states in ${}^{71}\mathrm{Ga}$ are crucial for studying low-energy solar neutrinos and the Ga anomaly, i.e., the possible transition to the sterile state. The responses for the ground state, the first excited state, and the second excited state are evaluated for the first time using the experimental electron capture rates, the experimental charge exchange reaction (CER) rates corrected for the tensor-interaction effect and the theoretical interacting shell model (ISM) calculations. The contributions from the two excited states to the solar and ${}^{51}\mathrm{Cr}$ neutrinos are found to be $4.2\pm 1.2\%$ of that for the ground state. This is slightly larger than the ISM values but little smaller than the CER values without corrections for the tensor interaction effect. The Ga anomaly is far beyond the uncertainty of the obtained nuclear responses.

    ↳ nucl-thhep-phnucl-exPRC(2026)·0 citations
22. 22*

    Entropy bounds from quantum thermodynamics

    Massimo Giovannini🇨🇭

    Within an inherently classical perspective, there is always an unavoidable energy cost associated with the information deletion and this common lore is at the heart of the Landauer's conjecture that does not impose, per se, any relevant limit on the information acquisition. Although such a mindset should generally apply to systems of any size, its quantum mechanical implications are particularly intriguing and, for this reason, we examine here a minimal physical structure where the system and the environment are described, respectively, by a pair of quantum oscillators coupled by an appropriate Hermitian interaction able to amplify the entropy of the initial state. Since at the onset of the dynamical evolution the system is originally in a pure state, its entropy variation is always positive semidefinite and the Landauer's conjecture should not impose any constraint. Nonetheless, provided the quantum amplification is effective, it turns out that the entropy variation of the system always undershoots the heat transferred to the environment. When the initial thermal state of the environment is characterized by a chemical potential, the entropy growth is bounded both by the particles and by the heat flowing to the environment. The limits deduced in the quantum thermodynamical framework are also scrutinized from a field theory standpoint where species of different spins are copiously produced (especially in a cosmological context) thanks to the rapid variation of the space-time curvature.

    ↳ quant-phastro-ph.COgr-qchep-ph+1PRD(2025)·0 citations
23. 23*

    The axial-vector form factor of the nucleon in a finite box

    Felix Hermsen🇳🇱 · Tobias Isken🇩🇪 · Matthias F. M. Lutz🇩🇪 · Rob G. E. Timmermans🇳🇱

    We consider the axial-vector form factor of the nucleon in a finite box. Starting from the chiral Lagrangian with nucleon and Delta-isobar degrees of freedom, we address, at the one-loop level, the impact of two types of finite-volume effects. On the one hand, there are the implicit effects from the in-box values of the nucleon and Delta-isobar masses. On the other hand, there are the explicit effects caused by computing the in-box loop integrals with the values of the nucleon and Delta-isobar masses obtained in the infinite-volume limit. Selected numerical results are shown for three lattice ensembles. We show that the implicit effects dominate the in-box form factor. Our results are presented in terms of a set of basis functions that generalize the Passarino-Veltman reduction scheme to the finite-box case, such that only scalar loop integrals have to be performed. The techniques we developed are more generally relevant for lattice studies of hadronic quantities.

    ↳ hep-lathep-ph3 citations
24. 24*

    Enhancement of primordial curvature perturbations in $R^3$-corrected Starobinsky-Higgs inflation

    Jinsu Kim🇨🇳 · Xinpeng Wang🇨🇳 · Ying-li Zhang🇨🇳 · Zhongzhou Ren🇨🇳

    We provide a systematic study of the Starobinsky-Higgs inflation model in the presence of an additional cubic term of the Ricci scalar. We investigate, in particular, the effects of the cubic term on the spectral index $n_s$ and the tensor-to-scalar ratio $r$. Through both analytical and numerical analyses, we show that the $R^3$-corrected Starobinsky-Higgs model can achieve compatibility with cosmic microwave background observations while producing distinct observational signatures with different frequency ranges. In addition, we discuss the complementarity between different observational probes, including the scalar-induced gravitational waves and spectral distortions, offering an independent probe of the enhanced curvature perturbations. Detection prospects are also discussed.

    ↳ astro-ph.COgr-qchep-phJCAP(2025)·67 citations
25. 25*

    QCD${}_2$ 't Hooft model: 2-flavour mesons spectrum

    Aleksandr Artemev🇷🇺 · Alexey Litvinov🇷🇺 · Pavel Meshcheriakov🇷🇺

    We continue analytical study of the meson mass spectrum in the large-$N_c$ two-dimensional QCD, known as the 't Hooft model, by addressing the most general case of quarks with unequal masses. Based on our previous work, we develop non-perturbative methods to compute spectral sums and systematically derive large-$n$ WKB expansion of the spectrum. Furthermore, we examine the behavior of these results in various asymptotic regimes, including the chiral, heavy quark, and heavy-light limits, and establish a precise coincidence with known analytical and numerical results obtained through alternative approaches.

    ↳ hep-thhep-phmath-phmath.MPPRD(2025)·13 citations
26. 26*

    Can asteroid-mass PBHDM be compatible with catalyzed phase transition interpretation of PTA?

    Jiahang Zhong🇨🇳 · Chao Chen🇨🇳 · Yi-Fu Cai🇨🇳

    Primordial black holes (PBHs) can catalyze first-order phase transitions (FOPTs) in their vicinity, potentially modifying the gravitational wave (GW) signals from PTs. In this study, we investigate the GWs from strong PTs catalyzed by PBHs. We consider high PBH number densities, corresponding to asteroid-mass PBH dark matter (DM) when the GWs from FOPTs peak in the nanohertz band. We calculate the PBH-catalyzed FOPT GWs from both bubble collision GWs and scaler-induced gravitational waves (SIGWs). We find that while low PBH number densities amplify the GW signals due to the formation of large bubbles, high PBH number densities suppress them, as the accelerated phase transition proceeds too rapidly. This suppression renders the signals unable to explain pulsar timing array (PTA) observations. By conducting data fitting with the NANOGrav 15-year dataset, we find that the PBH catalytic effect significantly alters the estimation of PT parameters. Notably, our analysis of the bubble collision GWs reveals that, the asteroid-mass PBHs ($10^{-16}-10^{-12}{M}_{\odot }$) as the whole dark matter is incompatible with the PT interpretation of pulsar timing array signals. However, incorporating SIGWs can reduce this incompatibility for PBHs in the mass range $10^{-14}-10^{-12}{M}_{\odot }$.

    ↳ astro-ph.COgr-qchep-phJCAP(2025)·6 citations
27. 27*

    Global $\Lambda$ polarization in heavy-ion collisions at high baryon density

    Yu. B. Ivanov🇷🇺

    Based on the model of three-fluid dynamics (3FD), the global $\Lambda$ polarization ($P_{\Lambda }$) is calculated in Au+Au collisions at 3 $\le \sqrt{s_{NN}}\le$ 9 GeV, in which high baryon density is achieved. Various contributions to $P_{\Lambda }$ are considered: those from the thermal vorticity, meson field, thermal shear and spin-Hall effect. Feed-down from higher-lying resonances is also taken into account. The results are compared with available data. Special attention is payed to the collision energies of $\sqrt{s_{NN}}=$ 3, 3.2, 3.5, 3.9, and 4.5 GeV, for which a thorough scan of the energy, rapidity, and centrality dependence of $P_{\Lambda }$ is performed. The results for 3 GeV reasonably well reproduce the corresponding STAR data. While the results at $\sqrt{s_{NN}}=$ 3.2, 3.5, 3.9, and 4.5 GeV can be considered as predictions for results of measurements within the STAR fixed-target (STAR-FXT) programthat are expected in the nearest future. It is predicted that a broad maximum of $P_{\Lambda }$ is reached at $\sqrt{s_{NN}}\approx$ 3--3.9 GeV, exact position of which depends on the centrality and width of the midrapidity range of observation. Impact of the meson-field, thermal-shear and spin-Hall-effect contributions to $P_{\Lambda }$ is also studied.

    ↳ nucl-thhep-phnucl-exPRC(2025)·4 citations
28. 28*

    Sound waves from primordial black hole formations

    Zhuan Ning🇨🇳 · Xiang-Xi Zeng🇨🇳 · Zi-Yan Yuwen🇨🇳 · Shao-Jiang Wang🇨🇳 · Heling Deng🇺🇸 · Rong-Gen Cai🇨🇳

    We present a numerical investigation of primordial black hole (PBH) formation from super-horizon curvature perturbations and the subsequent generation and propagation of sound waves, which can serve as a new source of stochastic gravitational wave backgrounds (SGWBs) presented in a companion letter. Using the Misner-Sharp formalism with an excision technique, our simulations extend to significantly later times than previous work and indicate that the near-critical perturbations produce a distinct compression wave featuring both overdense and underdense shells, while significantly supercritical perturbations yield only an underdense shell. We also show that a softer equation of state suppresses the formation of compression waves. Furthermore, the comoving thickness of sound shells remains nearly constant during propagation and scales with the Hubble radius at horizon re-entry, thereby serving as a key link between the gravitational-wave peak frequency and PBH mass in the companion letter. These results offer new insights into the dynamics of PBH formation and suggest potential observational signatures of PBHs in the gravitational wave (GW) spectrum from associated sound waves.

    ↳ gr-qcastro-ph.COhep-phPRD(2026)·14 citations
29. 29*

    Long-time soliton dynamics via a coarse-grained space-time method

    Dung N. Pham🇺🇸 · Zoe Zager🇺🇸 · Wentao Fan🇺🇸 · Hakan E. Türeci🇺🇸

    We investigate the long-time dynamics of the Sine-Gordon (SG) model under a class of perturbations whose quantum field theoretic analog - via bosonization - corresponds to the massive Schwinger model describing 1+1D relativistic QED of Dirac fermions. Classical SG solutions offer critical insight into non-perturbative effects in this quantum theory, but capturing their long-time behavior poses significant numerical challenges. To address this, we extend a coarse-graining method to spacetime using a dual-mesh construction based on the Minkowski-metric. We first validate the approach against the well-studied variant of the SG model describing magnetic fluxon dynamics in Josephson transmission lines (JTLs), where analytical and numerical benchmarks exist. We then apply the method to the Schwinger-inspired SG model and uncover long-lived bound states - "Schwinger atoms" - in which a soliton is trapped by a fixed central charge. In certain regimes, the system exhibits limit cycles that give rise to positronium-like states of oppositely charged solitons, while in others such formation is suppressed. Accessing such long-time solutions requires a rigorous implementation of outgoing boundary conditions on a finite computational domain that provide radiative dissipation to allow relaxation toward states that exist only in an infinite domain. Here we provide such a construction. Our results also suggest the possibility of analog quantum simulation of relativistic quantum field theories with JTLs. These results demonstrate the utility of spatio-temporal coarse-graining methodology for probing non-perturbative structure formation in non-linear field theories.

    ↳ quant-phhep-phphysics.opticsPRA(2026)·1 citation
30. 30*

    Geometry of soft scalars at one loop

    Timothy Cohen🇨🇭 · Ipak Fadakar🇨🇭 · Andreas Helset🇨🇭 · Filippo Nardi🇨🇭

    We extend the soft theorems for scattering amplitudes of scalar effective field theories to one-loop order. Our analysis requires carefully accounting for the fact that the soft limit is not guaranteed to commute with evaluating IR-divergent loop integrals; new results for the soft limit of general scalar one-loop integrals are presented. The geometric soft theorem remains unmodified for any derivatively-coupled scalar effective field theory, and we conjecture that this statement holds to all orders. In contrast, the soft theorem receives nontrivial corrections in the presence of potential interactions, analogous to the case of non-Abelian gauge theories. We derive the universal leading-order correction to the scalar soft theorem arising from potential interactions at one loop. Explicit examples are provided that illustrate the general results.

    ↳ hep-thhep-phJHEP(2025)·12 citations
31. 31*

    A Model of Realistic Flavor Symmetry: Origin of Fermion Mass, Flavor Mixing and Leptogenesis

    Wei-Min Yang🇨🇳

    I proposed a unified model of particle physic and cosmology in \cite {1}, which can simultaneously account for these origin of the inflation, dark energy, dark matter, neutrino mass and baryon asymmetry. I here focus on the fermion flavor issues in the unified model, which were not addressed previously. I introduce a realistic flavor symmetry to generate the fermion mass and mixing, from which we naturally derive the relationship between the quark mixing and the lepton mixing, and reveal the source of the difference between them. In particular, I derive a neutrino mass matrix which has a special structure form and only contains four parameters, but its numerical solutions are exactly accurately fitting to all the measured data of the neutrino mass spectrum and lepton mixing, and finely predict $m_{{\nu }_2}=0.01037$ eV. In addition, I discuss a new scenario of the leptogenesis in the model, which arises from two CP-asymmetric decays of a super-heavy neutral Dirac fermion, its CP asymmetry is closely related to the neutrino mass and mixing, via which we can correctly predict the baryon asymmetry. Lastly, I give several approaches to test the model. In short, the model can simply and elegantly account for the fermion flavor issues and the baryon asymmetry, and it has realistic and testable significance, therefore we expect the ongoing and future experiments to test the model.

    ↳ physics.gen-phhep-ph0 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.