Tue·Jan 28, 2025Tuesday·January 28, 2025

1. 01*

   Probing small-scale power spectrum with gravitational-wave diffractive lensing

   Sungjung Kim🇰🇷 · Han Gil Choi🇰🇷 · Sunghoon Jung🇰🇷

   We develop a novel way to probe subgalactic-scale matter distribution with diffractive lensing on gravitational waves. Five-year observations from Einstein Telescope and DECIGO are expected to probe $k=10^5\sim 10^8{\mathrm{Mpc}}^{-1}$ down to $P(k)=10^{-16}\sim 10^{-14}{\mathrm{Mpc}}^3$ level. These results can be interpreted in terms of primordial black holes in the range $M_{\mathrm{PBH}}\gtrsim 10^{-3}{M}_{\odot }$ down to $f_{\mathrm{PBH}}=10^{-6}$ level, or QCD axion minihalos in the range $m_a=10^{-3}\sim 10^{-12}\mathrm{eV}$. A key result of the paper is the approximate relation between the scale $k$ and the gravitational wave frequency $f$, derived in an ensemble of `multi-lensing' events. This relation enables direct measurement of the power spectrum at specific scales, with sensitivities characterized by model-independent kernels $\delta P(k)$. Additionally, we delineate the statistical properties of `multi-lensing' based on the `Fresnel number' $N_F$. When $N_F\gtrsim \mathcal{O}(1)$, the statistical significance can be approximately calculated by Variance of lensing effects, which is directly related to the power spectrum among other moments of matter distribution.

   hep-phastro-ph.COJHEP(2025)·7 citations
2. 02*

   Comparing strange and non-strange quark stars within resummed QCD at NLO

   Tulio E. Restrepo🇺🇸 · Jean-Loïc Kneur🇫🇷 · Constança Providência🇵🇹 · Marcus Benghi Pinto🇧🇷

   We employ the renormalization group optimized perturbation theory (RGOPT) resummation method to evaluate the equation of state (EoS) for strange ($N_f=2+1$) and non-strange ($N_f=2$) cold quark matter at NLO. This allows us to obtain the mass-radius relation for pure quark stars and compare the results with the predictions from perturbative QCD (pQCD) at NNLO. Choosing the renormalization scale to generate maximum star masses of order $M=2-2.6M_{\odot }$, we show that the RGOPT can produce mass-radius curves compatible with the masses and radii of some recently observed pulsars, regardless of their strangeness content. The scale values required to produce the desired maximum masses are higher in the strange scenario since the EoS is softer in this case. The possible reasons for such behavior are discussed. Our results also show that, as expected, the RGOPT predictions for the relevant observables are less sensitive to scale variations than those furnished by pQCD.

   hep-phastro-ph.HEnucl-thPRD(2025)·7 citations
3. 03*

   Geomagnetic constraints on Millicharged Dark Matter

   Ariel Arza🇨🇳 · Yuanlin Gong🇨🇳 · Jing Shu🇨🇳 · Lei Wu🇨🇳 · Qiang Yuan🇨🇳 · Bin Zhu🇨🇳

   Millicharged particles are well-motivated dark matter candidates arising in many extensions of the Standard Model. We show that, despite their tiny coupling $e_m$ to photons, millicharged dark matter (mDM) in the Earth's geomagnetic field can generate a quasi-static, monochromatic magnetic signal with angular frequency twice the mDM mass. Using null results from the SuperMAG and SNIPE Hunt collaborations, we constrain the effective charge of bosonic mDM in the mass range $10^{-18}$--$10^{-14}\text{eV}$. The resulting upper bounds exceed stellar cooling constraints by over thirteen orders of magnitude, demonstrating the power of this method.

   hep-phPRL(2026)·13 citations
4. 04*

   Exclusive $\eta$ production in proton-proton collisions at energies available at the GSI Facility for Antiproton and Ion Research

   Piotr Lebiedowicz🇵🇱

   The cross sections for the $pp\to pp\eta$ reaction are evaluated at energies relevant for the HADES, PANDA, and SIS100 experiments at GSI-FAIR. Consideration includes the $\eta$-bremsstrahlung mechanism involving intermediate proton exchange via the ${\pi }^0$, $\eta$, ${\rho }^0$, and $\omega$ exchanges and the mechanism involving the nucleon resonances $N(1535)$, $N(1650)$, $N(1710)$, and $N(1880)$ excited via the pseudoscalar- and/or vector-meson exchanges, depending on the model. The role of the $\omega \omega$- and ${\rho }^0{\rho }^0$-fusion processes with the reggeized vector-meson exchanges is also discussed. The calculation is done in an effective Lagrangian approach. To determine the parameters of the model, the $\gamma p\to \eta p$ and ${\pi }^{-}p\to \eta n$ reactions are studied and the results are then compared with the Crystal Ball and CLAS data. For the $pp\to pp\eta$ reaction, the model results are compared with the energy dependence of the cross section measured far from the threshold and with the differential distributions $d\sigma /d\cos {\theta }_{\eta }$ and $d\sigma /d{p}_{\eta }$ measured by the DISTO Collaboration. The comparison shows that the $N(1535)$ resonance is the dominant contribution and that other contributions are also important due to interference effects. Assuming that the $\rho$ exchange is the dominant resonant excitation process, the model is able to describe the available data, e.g., it reproduces the shape of the angular distributions measured by the DISTO Collaboration. Predictions are given for the HADES experiment at center-of-mass energy of $\sqrt{s}=3.46$ GeV, which can be verified in the near future, and for planned PANDA and SIS100 experiments at higher energies.

   hep-phhep-exPRC(2025)·0 citations
5. 05*

   Several problems on the measured hyperorder cumulants of net-proton distributions in heavy-ion collisions

   Lizhu Chen🇨🇳 · Ye-Yin Zhao🇨🇳 · Zhiming Li🇨🇳 · Yuanfang Wu🇨🇳

   Hyperorder cumulants $C_5/C_1$ and $C_6/C_2$ are recommended as sensitive observables to explore the QCD phase transition in heavy-ion collisions. Precisely measuring their results remains a difficult task in experiments, when employing the Centrality Bin Width Correction (CBWC) to suppress the initial volume fluctuations. Various techniques within the CBWC formula can lead to notable differences in the results. We will systematically investigate the application of the CBWC method to the measured net-proton $C_5/C_1$ and $C_6/C_2$ using the UrQMD model and Skellam-based simulations at $\sqrt{s_{NN}}$ = 11.5 GeV in Au + Au collisions. A recommended approach is proposed to calculate $C_5/C_1$ and $C_6/C_2$ in 0-40\% centrality. With statistics comparable to the RHIC Beam Energy Scan phase II (BES-II), our studies provide a baseline for analyzing net-proton $C_5/C_1$ and $C_6/C_2$ in relativistic heavy-ion collisions.

   hep-phhep-exJ.Phys.G(2025)·0 citations
6. 06*

   Supercooled Phase Transitions: Why Thermal History of Hidden Sector Matters in Analysis of Pulsar Timing Array Signals

   Jinzheng Li🇺🇸 · Pran Nath🇺🇸

   The detection of a gravitational wave background in the nano-Hertz frequency range from Pulsar Timing Array (PTA) observations offers new insights into evolution of the early universe. In this work we analyze gravitational wave data from PPTA, EPTA, and NANOGrav, as arising from a supercooled first-order phase transition within a hidden sector, characterized by a broken $U(1{)}_X$ gauge symmetry. Several previous works have discussed challenges in producing observable {PTA signal} from supercooled phases transitions. We discuss these challenges and show how they are overcome by inclusion in part of the proper thermal history of the hidden and the visible sectors. The analysis of this work demonstrates that thermal histories of hidden and visible sectors profoundly influence the gravitational wave power spectrum, an aspect not previously explored in the literature. Further, the analysis of this work suggests that supercooled phase transitions not only align with the Pulsar Timing Array observations but also show promise for gravitational wave detection by future gravitational wave detectors. Our analysis shows that the dominant contribution to the gravitational wave power spectrum for PTA signals comes from bubble collision while the sound wave and turbulence contributions are highly suppressed. It is also found that all the PTA events are of detonation type while deflagration and hybrid events are absent. The analysis presented in this work provides a robust framework for further investigations on the origin of gravitational wave power spectrum in the early universe and for their experimental observation in the future.

   hep-phastro-ph.HEPRD(2025)·18 citations
7. 07*

   Bottomonia in an unquenched quark model

   Ru-Hui Ni🇨🇳 · Qian Deng🇨🇳 · Jia-Jun Wu🇨🇳 · Xian-Hui Zhong🇨🇳

   The bottomonium spectrum is systematically studied within an unquenched quark model. Based on a good description of both the masses and widths for the well-established states, we further give predictions for the higher $S$-, $P$-, and $D$-wave bottomonium states up to a mass region of $\sim 11.3$ GeV. For the vector states, the $S$-$D$ mixing and dielectron decays are studied. Additionally, to understand the role of the higher vector resonances in the $e^{+}{e}^{-}$ annihilation reaction, we evaluate the cross section by combining our quark model predictions for the mass, dielectron and strong decay properties. It is found that (i) The mass shifts of the high $b\bar{b}$ states due to the coupled-channel effects are the order of a few tens MeV, most of the high-lying resonances contain significant non-$b\bar{b}$ components. (ii) The ${{\rm Y}}_1(3D,5D,6D)$ states significantly mix with ${\rm Y}(4S,6S,7S)$, respectively, which is mainly induced by the intermediate hadronic loops. (iii) The non-$b\bar{b}$ components will lead a significant suppression for the dielectron decay widths of some vector resonances.(iv) The threshold effects of open-bottom meson pairs can cause rich bump structures in the cross section of $e^{+}{e}^{-}\to b\bar{b}$. Our model shows that the ${\rm Y}(10753)$ may arise from threshold effects due to the strong coupling between ${\rm Y}(4S)$ and ${\bar{B}}^{\ast }{B}^{\ast }$.

   hep-phhep-exPRD(2025)·14 citations
8. 08*

   Are Parton Showers in a Quark-Gluon Plasma Strongly Coupled? A Theorist's Test

   Peter Arnold🇺🇸 · Omar Elgedawy🇺🇸 · Shahin Iqbal🇵🇰

   We study whether in-medium showers of high-energy quarks and gluons can be treated as a sequence of individual splitting processes or whether there is significant quantum overlap between where one splitting ends and the next begins. Accounting for the Landau-Pomeranchuk-Migdal (LPM) effect, we calculate such overlap effects to leading order in high-energy ${\alpha }_s(\mu )$ for the simplest theoretical situation. We investigate a measure of overlap effects that is independent of physics that can be absorbed into an effective value ${\hat{q}}_{eff}$ of the jet-quenching parameter $\hat{q}$.

   hep-phPoS(2025)·0 citations
9. 09*

   Study on the Distribution Amplitude of the Scalar Meson $K_0^{\ast }(1430)$

   Chen Wang🇨🇳 · Yuanyuan Ma🇨🇳 · Zhijun Wang🇨🇳 · Yanjun Sun🇨🇳

   Based on sum rules, we explore the twist-2 distribution amplitude of the $K_0^{\ast }(1430)$ meson, treating it as the ground state of a quark-antiquark system. We posit that the spacetime distance $x$ should be infinitesimally close to the quark separation $z$. By incorporating quark distance corrections, with $x^2\approx z^2\approx xz$, the calculated moments yield additional insights. Moreover, we employ light-cone sum rules to compute the form factors for the semi-leptonic decay process $B_s\to K$. The reliability of the computed distribution amplitude is confirmed through its comparison with the form factor.

   hep-phnucl-th0 citations
10. 10*

    Improved global determination of two-meson distribution amplitudes from multi-body $B$ decays

    Da-Cheng Yan🇨🇳 · Hsiang-nan Li🇹🇼 · Zhou Rui🇨🇳 · Zhen-Jun Xiao🇨🇳 · Ya Li🇨🇳

    We improve the perturbative QCD (PQCD) formalism for multi-body charmless hadronic $B$ meson decays, such as $B\to V{P}_3\to P_1{P}_2{P}_3$, by resolving the possible discrepancy in parametrizing the contribution of the $P$-wave resonance $V$ to the two-meson distribution amplitudes (DAs) associated with the pairs $P_1{P}_2=\pi \pi ,K\pi ,KK$. The determination of the Gegenbauer moments in the two-meson DAs is then updated in the global fit of the improved PQCD factorization formulas at leading order in the strong coupling ${\alpha }_s$ to available data for branching ratios and polarization fractions of three- and four-body $B$ decays. The convergence of the Gegenbauer expansion of the resultant two-meson DAs is manifest. The satisfactory quality of the fit implies the consistency of the PQCD framework for multi-body $B$ decays and the universality of the nonperturbative two-meson DAs. In particular, the predicted longitudinal polarization fraction $f_0(B_s^0\to K^{\ast 0}{\bar{K}}^{\ast 0})=28.2_{-9.5}^{+8.8}\%$ with the updated Gegenbauer moments matches well the measurement. The observable $L_{K^{\ast 0}{\bar{K}}^{\ast 0}}=7.7_{-3.8}^{+4.9}$, defined as the ratio of the longitudinal amplitudes of the two $U$-spin related channels $B_s^0\to K^{\ast 0}{\bar{K}}^{\ast 0}$ and $B^0\to K^{\ast 0}{\bar{K}}^{\ast 0}$, accommodates the current data within errors. It is found that the direct $CP$ asymmetries ${\mathcal{A}}_{\mathrm{CP}}^{0,||,\perp }$ in the polarization states of some four-body decays $B\to V_1{V}_2\to (P_1{P}_2)(P_3{P}_4)$ might be large, but the destruction among them result in small net $CP$ violation. Our predictions can be confronted with LHCb and Belle-II data in the future.

    hep-phEPJC(2025)·6 citations
11. 11*

    Roles of $\Delta (1232)$, $N^{\ast }(1520)$, and $N^{\ast }(1650)$ resonances in $\gamma p\to {\pi }^0{\pi }^{0}p$ reaction within an effective Lagrangian approach

    Meng-Yuan Dai🇨🇳 · Si-Wei Liu🇨🇳 · Cheng Chen🇨🇳 · De-Min Li🇨🇳 · En Wang🇨🇳 · Ju-Jun Xie🇨🇳

    Roles of the $\Delta (1232)$, $N^{\ast }(1520)$, and $N^{\ast }(1650)$ resonances in the $\gamma p\to {\pi }^0{\pi }^{0}p$ reaction near threshold is investigated within an effective Lagrangian approach. We have calculated the differential cross sections of the $\gamma p\to {\pi }^0{\pi }^{0}p$ reaction by including the contributions from the $\Delta (1232)$, $N^{\ast }(1520)$, and $N^{\ast }(1650)$ intermediate states decaying into ${\pi }^{0}p$ via the $s$-channel nucleon pole and $t$-channel $\rho$ exchange, and found that the current experimental measurements can be well reproduced. The production of $\Delta (1232)$ is mainly from the mechanism of the $s$-channel nucleon pole, while the $N^{\ast }(1520)$ and $N^{\ast }(1650)$ are produced from the mechanism of the $t$-channel $\rho$ exchange. It is expected that more experimental data on the $\gamma p\to {\pi }^0{\pi }^{0}p$ reaction can be used to explore the properties of the low-lying excited baryon states and also the scalar $f_0(500)$ and $f_0(980)$ mesons.

    hep-phnucl-thCPC(2025)·6 citations
12. 12*

    Investigate the glueball-like particle $X(2370)$ in $B$ meson decays

    Xiao-Tong Li🇨🇳 · Guang-Yu Wang🇨🇳 · Qi-An Zhang🇨🇳

    Based on the collected data on $J/\psi \to \gamma K_S^0{K}_S^0{\eta }^{\prime }$, the BESIII experiment has conducted an analysis of the mass and spin parity of the $X(2370)$ particle. The findings are consistent with the characteristics expected of the lightest pseudoscalar glueball. We point out that further exploration of this particle's nature can be pursued through investigations of heavy bottom meson decays. Assuming the identity of $X(2370)$ as a pseudoscalar glueball, we compute the form factors for $B\to X(2370)$ transitions in the factorization approach. With these results, the estimated branching fractions for semileptonic $B$ decays into $X(2370)$ can reach the order of $10^{-6}$ and those for nonleptonic decays can reach the order $10^{-8}$. These results suggest that decays of $B$ meson into $X(2370)$ are detectable at experimental facilities like Belle-II. Future experimental endeavors hold promise in expanding our understanding of glueball physics, contributing to the ongoing exploration surrounding this intriguing particle.

    hep-phEPJC(2025)·9 citations
13. 13*

    VacuumTunneling: A package to solve bounce equation with renormalization factor

    Banghui Hua🇨🇳 · Jiang Zhu🇨🇳

    The Vacuum tunneling rate $\Gamma$ from the effective action is a key to studying the cosmological first-order phase transition(FOPT). One solid way to compute the $\Gamma$ is to start with the derivative expansion of the effective action and solve the bounce equation numerically. In this process, the renormalization factor $Z$ of the tunneling field may play a center rule, which is not considered in existing packages. Therefore, we present a \texttt{Mathematica} package \vt to compute the bounce action with or without the renormalization factor. Applying the \vt package, we find that the presence of $Z$ has a significant impact on the action, as well on the tunneling path. We provide some concrete examples to demonstrate the difference between the solution with and without the renormalization factor, both in the action and tunneling path. This package is based on the modified shooting and path deformation method. We also made some optimizations for the super-cooling phase transition(thick wall scenario), in which other numerical package works poorly. This package works as long as the expressions can give values of the potential and the renormalization at a certain field point. This means the input potential and the renormalization can be merely numerical quantities without analytical expressions. The computation time can be as short as 1 second in single-field tunneling and several seconds in multi-field cases.

    hep-phastro-ph.COComput.Phys.Commun.(2025)·6 citations
14. 14*

    One-loop induced contributions to the rare decay of $A_0\to h_0{h}_0\gamma$ in Two Higgs Doublet Models

    Dzung Tri Tran (Duy Tan Univ.)🇻🇳 · L. T. Hue (VLU)🇻🇳 · Thanh Huy Nguyen (HCMUS)🇻🇳 · Vo Quoc Phong (HCMUS)🇻🇳 · Khiem Hong Phan (Duy Tan Univ.)🇻🇳

    The analytic expressions for one-loop contributions to the rare decay process $A_0\to h_0{h}_0\gamma$ within the CP-conserving of Two Higgs Doublet Models are first reported in this paper. Analytic results are presented in term of scalar one-loop Passarino-Veltman functions following the standard output of the packages~{\tt LoopTools} and {\tt Collier}. In this context, physical results for the computed process are easily generated by using one of these packages. The numerical checks are proposed to verify for the analytic results in this paper. The checks rely on the renormalization conditions that the decay amplitude must be the ultraviolet finiteness and infrared finiteness. The amplitude consisting of an external photon always obeys the Ward identity. This will be confirmed numerically in this article. In phenomenological results, the decay rates of $A_0\to h_0{h}_0\gamma$ are evaluated at several points in the allowed regions of the parameter space. Furthermore, the differential decay widths with respect to the invariant mass of Higgs-pair in final states are studied.

    hep-ph1 citation
15. 15*

    Dark Chiral Phase Transition Driven by Chemical Potential and its Gravitational Wave Test

    Zhaofeng Kang🇨🇳 · Jiang Zhu🇨🇳

    In this article, for the first time, we explore the scenario that the dark-QCD sector has a large chemical potential $\mu$ (on the order of magnitude of temperature) of dark quarks. It leads to a complex-valued Polyakov loop and tilts the partial confinement effect, driving the dark-QCD phase transition to a first-order one in the early universe. We present a toy model via the Affleck-Dine mechanism that could generate degenerate dark quarks. Our study, in the framework of PNJL, focuses on the dynamical impacts of a large chemical potential on the chiral phase transition without turning on the KMT instanton term. We plot the phase diagram of the dark-QCD in the chiral limit. The resulting first-order phase transition actually refers to a chiral phase transition, with the transition to the confinement vacuum being a cross-over. Following the phase diagram, we find that increasing $\mu$ can considerably prolong the duration of the phase transition and also the release of latent heat, which together make the cosmic dark-QCD phase transition at the critical temperature above 1 GeV and below 100 GeV produce gravitational wave signal in the intermediate frequency band, which is well probable in space detectors such as BBO

    hep-phhep-thJHEP(2025)·6 citations
16. 16*

    Probing ALP couplings to electroweak gauge bosons

    Jin Sun🇰🇷 · Zhi-Peng Xing🇨🇳 · Seokhoon Yun🇰🇷

    Motivated by the more and more abundant experimental data, we revisit the couplings of axion-like particle (ALP) to electroweak gauge bosons across the ALP mass range from MeV to 100 GeV. The current and future experimental limits on the couplings are extended. The ALP coupling to $W$-bosons gives rise to flavor-changing ALP-quark couplings at the one-loop level. These flavor-changing couplings deserve further investigation under current experimental constraints, especially those stemming from rare meson decays and neutral meson mixing processes. Additionally, flavor-conserving couplings of the ALP to Standard Model (SM) fermions arise at the one-loop level as well from ALP-electroweak gauge boson couplings, even in the absence of tree-level couplings to these SM fermions, with consequent ALP decays to the SM fermions leading to constraints on the ALP-electroweak gauge boson couplings. We also investigate processes relevant to $Z$-boson measurements, such as the invisible decay $Z\to a\gamma$, subsequent decays $Z\to 3\gamma$ and $Z\to \gamma ll$, as well as constraints from oblique parameters ($S,T,U$). Our study highlights that rare two-body decays of pseudoscalar mesons offer the most sensitive probes of ALP couplings to electroweak gauge bosons from the loop-induced flavor-violating interactions for ALP masses below the kinematic threshold, while $Z$-boson decays complementarily explore larger ALP masses. Future lepton colliders, such as CEPC and FCC-ee operating at the $Z$-pole, along with SHiP, provide further opportunities to probe ALP couplings to electroweak gauge bosons.

    hep-phCPC(2025)·6 citations
17. 17*

    Effective Lepton Flavor Violating couplings at Muon Collider

    Sukanta Dutta🇮🇳 · Purnath Unnikrishnan🇮🇳 · Yashasvi🇮🇳

    We estimate the sensitivity of Wilson coefficients of the lepton flavor-violating dimension-six operators at the proposed ${\mu }^{+}{\mu }^{-}$ collider. We compute the signal significance at $\sqrt{s}$ = 3 and 10 TeV, respectively, with an integrated luminosity of 1 and 10 ab${}^{-1}$ corresponding to unpolarized and polarized initial muon beams. Using the optimal observable method for the kinematic distributions, we study the measurement errors of the effective couplings at the 1-sigma level.

    hep-phhep-exSpringer Proc.Phys.(2026)·0 citations
18. 18*

    Searching for long-lived particles from stopped pions and muons at the CiADS-BDE

    Zeren Simon Wang🇨🇳 · Yu Zhang🇨🇳 · Liangwen Chen🇨🇳

    The CiADS-BDE is a beam-dump experiment recently proposed for searching for light, long-lived particles (LLPs) at China initiative Accelerator Driven System. Primarily thanks to the large numbers of protons on target at the experiment, it has been shown to be sensitive to large, unique regions of the parameter space of dark photon, with a small detector volume of $\mathcal{O}(0.01\text{–}1)$ m${}^3$. Here, we explore the search prospect of the CiADS-BDE for a series of new-physic models predicting LLPs that could emanate from decays at rest of charged pions and muons at the facility, namely, heavy neutral leptons, axionlike particles, and light binos in the R-parity-violating supersymmetry. For these benchmark models, we find that the CiADS-BDE can also probe vast parameter regions beyond the existing bounds.

    hep-phhep-ex2 citations
19. 19*

    Microscopic composite systems bound by strong gravity in extra dimensions as candidates for dark matter

    V. V. Flambaum🇦🇺

    In the Arkani-Hamed-Dimopoulos-Dvali (ADD) model with n extra compactified dimensions, the gravitational potential scales as 1/r^{n+1} and becomes significantly stronger at short distances. We investigate the possibility of forming small-sized composite systems of Standard Model particles bound by this potential. Such bound states, composed of quarks, neutrinos, axions, or other particles, exhibit a small cross-section-to-mass ratio, making them viable candidates for dark matter.

    hep-phastro-ph.COnucl-thphysics.atom-phPRD(2025)·2 citations
20. 20*

    Analysis of axion-like particles in a top-quark pair production at the CLIC

    S.C. İnan🇹🇷 · A.V. Kisselev🇷🇺

    We examine a contribution of axion-like particles (ALPs) to a top pair production via the collision of Compton backscattered photons at the CLIC operating in a $\gamma \gamma$ mode. The exclusion bounds on the ALP-top quark coupling depending on the ALP mass $m_a$ are given. The mass range 10 GeV -- 10 TeV is considered. We have obtained that for $m_a=10$ GeV the ALP-top quark couplings as small as $0.17$ TeV${}^{-1}$ and $0.11$ TeV${}^{-1}$ can be probed at the CLIC with the energy of 1.5 TeV and 3 TeV, respectively. A comparison with other constraints on the ALP-top coupling is given.

    hep-phhep-exEPJC(2025)·6 citations
21. 21*

    Finite size effects on the transport coefficients of strongly interacting QCD matter

    Dhananjay Singh🇮🇳 · Arvind Kumar🇮🇳

    The role of finite volume effects on the various transport coefficients of strongly interacting quark matter is analyzed in the Polyakov chiral SU(3) quark mean field model (PCQMF) at finite temperatures and chemical potentials incorporating fermionic vacuum term. Using a non-zero lower momentum cutoff and two different forms of the Polyakov loop potentials with quark back reaction, we study the following viscous properties: specific shear viscosity ($\eta /s$), normalized bulk viscosity (${\zeta }_b/s$), and conductivity properties: electrical conductivity (${\sigma }_{el}/T$), thermal conductivity ($\kappa /T^2$). Along with this, some essential thermodynamic quantities in the context of transport properties, such as the square of the speed of sound ($c_s^2$) and the specific heat ($c_v$) at a constant volume, are computed. Finite size effects are applied to the vacuum term and its influence on the effective quark masses, thermodynamic quantities, and transport coefficients is studied. The temperature dependence of the transport coefficients is obtained through the kinetic theory approach with the relaxation time approximation. The size of the system has been found to have significant effects on all transport coefficients. We find that all the transport coefficients increase as the size of the system is reduced. We have also studied the specific sound channel $(\eta +3{\zeta }_b/4)/s$ and the bulk-to-shear viscosity ratio ${\zeta }_b/\eta$. The effect of finite size is found to be more prominent in the transition region and vanishes at high $T$. The transition temperature $T_{\chi }$ is found to decrease as the system size (characterized by $R$) decreases. At finite chemical potentials, $T_{\chi }$ is shifted to lower values compared to the case of the vanishing chemical potential.

    hep-phPRD(2025)·8 citations
22. 22*

    Determination of ${\alpha }_s(M_Z)$ via a high-precision effective coupling ${\alpha }_s^{g_1}(Q)$

    Qing Yu🇨🇳 · Xing-Gang Wu🇨🇳 · Hua Zhou🇨🇳 · Jian-Ming Shen🇨🇳

    We propose a novel method to determine the strong coupling of quantum chromodynamics (QCD) and fix its running behavior at all scales by using the Bjorken sum rules (BSR). The BSR defines an effective coupling ${\alpha }_s^{g_1}(Q)$ which includes the nonperturbative high-twist corrections and perturbative QCD (pQCD) corrections to the leading-twist part. For the leading-twist part of ${\alpha }_s^{g_1}(Q)$, we adopt the infinite-order scale-setting procedure of the principle of maximum conformality (${\mathrm{PMC}}_{\infty }$) to deal with its pQCD corrections, which reveals the intrinsic conformality of series and eliminates conventional renormalization scheme-and-scale ambiguities. Using the ${\mathrm{PMC}}_{\infty }$ approach, we not only eliminate \textit{the first kind of residual scale dependence} due to uncalculated higher-order terms, but also resolve the previous ``self-consistence problem". The holographic light-front QCD model is used for ${\alpha }_s^{g_1}(Q)$ in the infrared region, which also reveals a conformal behavior at $Q\to 0$. As a combination, we obtain a precise ${\alpha }_s^{g_1}(Q)$ at all scales, which matches well with the known experimental data with $p$-value $\sim 99\%$, we determine the strong coupling constant at the critical scale $M_Z$, ${\alpha }_s(M_Z)=0.1191\pm 0.0012\mp 0.0006$, where the first error comes from $\Delta \kappa$ of LFHQCD model and the second error is from \textit{the second kind of residual scale dependence} that is negligible.

    hep-phPRD(2025)·1 citation
23. 23*

    Systematic analysis of the form factors of $B_c$ to $P$-wave charmonia and corresponding weak decays

    Jie Lu🇨🇳 · Dian-Yong Chen🇨🇳 · Guo-Liang Yu🇨🇳 · Zhi-Gang Wang🇨🇳 · Bin Wu🇨🇳

    In this article, the vector, axial vector and tensor form factors of $B_c\to {\chi }_{cJ}$ ($J=0,1,2$) and $B_c\to h_c$ are analyzed within the framework of three-point QCD sum rules. With the calculated vector and axial vector form factors, we directly study the decay widths and branching ratios of semileptonic decays $B_c^{-}\to {\chi }_{cJ}l{\bar{\nu }}_l,h_{c}l{\bar{\nu }}_l$ $(l=e,\mu$ and $\tau )$ and analyze the nonleptonic decays $B_c^{-}\to {\chi }_{cJ}{\pi }^{-},{\chi }_{cJ}{K}^{-},{\chi }_{cJ}{\rho }^{-},{\chi }_{cJ}{K}^{\ast -}$, $B_c^{-}\to h_c{\pi }^{-},h_c{K}^{-},h_c{\rho }^{-},h_c{K}^{\ast -}$ by using the naive factorization approach (NFA). These results can provide more information to understand the properties of $B_c$ meson and $P$-wave charmonia and to study the heavy quark dynamics.

    hep-phPRD(2025)·7 citations
24. 24*

    The First Particles

    Fa Peng Huang🇨🇳

    After cosmic inflation, the universe is cold and almost empty. Thus, the inflation field should decay to the particles for BBN through the so-called reheating process. Later, the matter-antimatter asymmetry and dark matter are produced. In this chapter, the ``first particle" production between the inflation phase and BBN phase is introduced. We focus on the reheating, electroweak baryogenesis, and leptogenesis.

    hep-ph8 citations
25. 25*

    Double heavy quarkonia production with color-octet channels at Z factory and at the CEPC/FCC-ee

    Xiao-Peng Wang🇨🇳 · Guang-Zhi Xu🇨🇳 · Kui-Yong Liu🇨🇳

    Within the NRQCD framework, we calculate the exclusive production of double heavy quarkonium(double charmonium and double bottomonium) at future super $Z$ factory and at the CEPC/FCC-ee. The color-octet(CO) channels in the ${\gamma }^{\ast }/Z^{\ast }$-propagated process are considered along with the color-singlet(CS) channels. We found that the contributions of CO states to the total cross section are significant or dominant for many processes within energy region at $Z$ factory and at the CEPC/FCC-ee. The experimental measurements will help us to verify the CO mechanism. Among these CO channels, the gluon fragmentation into ${}^3{S}_1^8$ states is most important. Thus, the comparison between the theoretical results and future data will give a strong constraint to the matrix elements $⟨\mathcal{O}\left({}^3{S}_1^{[8]}\right)⟩$. Additionally, we consider the relativistic corrections to both the CS and CO channels which decrease the cross sections significantly. Specially, the $K$ factors are about $0.5$ for most charmonium channels. We get estimates of the events for double heavy quarkonium production. The final events of $J/\psi +{\eta }_c$, $J/\psi +J/\psi$, ${\rm Y}+{\eta }_b$, ${\rm Y}+{\rm Y}$ production would be (22, 570, 71, 61) and (206, 5343, 665, 576) at the CEPC (2-year) and at the FCC-ee (4-year) for the $Z$ factory mode, respectively.

    hep-phPRD(2025)·3 citations
26. 26*

    Supercooled Dark Scalar Phase Transitions explanation of NANOGrav data

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

    The evidence of a Stochastic Gravitational Wave Background (SGWB) in the nHz frequency range is posed to open a new window on the Universe. A preferred explanation relies on a supercooled first order phase transition at the 100 MeV - GeV scale. In this article, we address the feasibility going from the particle physics model to the production of the gravitational waves. We take a minimal approach for the dark sector model introducing the fewest ingredients required, namely a new U(1) gauge group and a dark scalar that dynamically breaks the symmetry. Supercooling poses challenges in the analysis that put under question the feasibility of this explanation: we address them, going beyond previous studies by carefully considering the effects of a vacuum domination phase and explicitly tracking the phase transition from its onset to its completion. We find that the proposed model can successfully give origin to the observed PTA SGWB signal. The strong supercooling imposes a correlation between the new gauge coupling and the scalar quartic one, leading to a significant hierarchy between the (heavier) gauge boson and the dark scalar. Ultimately, information on phase transitions from SGWB observations could provide a direct probe of the microphysics of the Early Universe and be used to guide future searches of dark sector in laboratories.

    hep-phPLB(2025)·24 citations
27. 27*

    Ultra-cold neutrons in qBounce experiments as laboratory for test of chameleon field theories and cosmic acceleration

    Derar Altarawneh🇯🇴 · Roman Höllwieser🇩🇪

    The accelerating expansion of the Universe, attributed to dark energy, has spurred interest in theories involving scalar fields such as chameleon field theories. These fields, which couple to matter with density-dependent effective mass, offer a promising explanation for cosmic acceleration. Experiments leveraging ultra-cold neutrons (UCNs) provide an innovative approach to testing these theories. The existence of a chameleon field, being responsible for the current phase of cosmic acceleration, is investigated by analysing a free fall of ultra-cold neutrons from the gap between two mirrors after their bouncing between these two mirrors. We analyse a deformation of the wave functions of the quantum gravitational states of ultra-cold neutrons, induced by a chameleon field, and find a new upper bound $\beta \le 6.5\times 10^8$ on the chameleon-matter coupling constant $\beta$ from the unitarity condition. This result refines previous estimates and highlights the potential of ultra-cold neutron experiments as laboratories for exploring scalar field theories and fundamental physics.

    hep-phhep-thJ.Nucl.Energy(2025)·4 citations
28. 28*

    A radiative seesaw in a non-holomorphic modular $S_3$ flavor symmetry

    Hiroshi Okada🇨🇳 · Yuta Orikasa🇨🇿

    We study a non-holomorphic modular $S_3$ flavor symmetry in which we analyze neutrino sector, dark matter, and lepton flavor violations. The active neutrino mass is generated via one-loop level. We achieve chi-square analysis and demonstrate some predictions in cases of normal hierarchy with fermionic or bosonic dark matter and inverted hierarchy of fermionic or bosonic dark matter.

    hep-phJCAP(2026)·20 citations
29. 29*

    The Signals of Doomsday I: False Higgs vacuum decay signatures

    Amartya Sengupta🇺🇸 · Dejan Stojkovic🇺🇸 · De-Chang Dai🇹🇼

    The measured standard model parameters indicate that we might live in a false Higgs vacuum, though with a very long lifetime. However, small black holes can serve as catalysers and significantly speed up the phase transition. In fact, bubbles of true vacuum might already exist in our universe. If the propagation of the bubble walls slows down due to interaction with the surrounding matter and plasma, these signals can reach us before the bubble wall hits us. Using the vacuum mismatch method, we calculate the spectrum of the Higgs particles produced by such a bubble until the terminal velocity is reached. In addition, we show that frictional dissipation at the terminal wall velocity generates a large population of thermally produced Higgs particles, which continues even after the mismatch channel shuts off. Since the Higgs is neutral, a good part of the final decay products (after hadronization, annihilation and decay of unstable particles) will be photons and neutrinos, which will then act as a long-range signature. For the conservative set of parameters used here, the thermal channel produces a macroscopically large burst of high energy neutrinos and photons from Higgs decays, which could be detectable from sufficiently nearby bubbles with current or upcoming multi messenger facilities.

    hep-phhep-thPhys.Dark Univ.(2026)·3 citations
30. 30*

    The charming case of $X(3872)$ and ${\chi }_{c1}(2P)$

    Pietro Colangelo🇮🇹 · Fulvia De Fazio🇮🇹 · Giuseppe Roselli🇮🇹

    More than twenty years have elapsed since the discovery of ${\chi }_{c1}(3872)$ (previously denoted as $X(3872)$), and an impressive amount of theoretical and experimental studies has been devoted to its properties, decays and production mechanisms. Despite the extensive work, a full understanding of the nature of ${\chi }_{c1}(3872)$ is still missing. In the present study we reconsider a theoretical framework based on the heavy quark large mass limit to analyse the radiative decays of heavy quarkonia, in particular the electric dipole transitions of ${\chi }_{c1}(2P)$ to S-wave charmonia. The results favourably compare to recent measurements for ${\chi }_{c1}(3872)$, obtained by the LHCb Collaboration, if this meson is identified with ${\chi }_{c1}(2P)$.

    hep-phhep-exhep-latPRD(2025)·10 citations
31. 31*

    Axion-like Particle Conversion in the Solar Magnetic Field

    Elisa Todarello🇬🇧

    Axion-like particles (ALPs), hypothetical extensions of the Standard Model, can convert into photons in an external magnetic field. Two recent studies~\cite{Todarello:2023ptf, Ruz:2024gkl} explored the phenomenology of ALP-photon conversion in the magnetic field of the solar atmosphere. Dark matter ALPs convert into radio photons and may be detected with next-generation radio interferometers, while ALPs produced in the solar core convert into X-rays. Thanks to solar observation acquired with the NuSTAR X-ray telescope, Ref.~\cite{Ruz:2024gkl} establishes stringent robust bounds on the ALP-photon coupling over a large portion of parameter space.

    hep-phastro-ph.COPoS(2025)·1 citation
32. 32*

    Further study on excited ${\Xi }_{Q{Q}^{\prime }}$ via photoproduction at CEPC and FCC-ee

    Hong-Hao Ma🇨🇳 · Juan-Juan Niu🇨🇳 · Lei Guo🇨🇳

    Within the framework of NRQCD, the photoproduction of doubly heavy baryons ${\Xi }_{cc}$, ${\Xi }_{bc}$, ${\Xi }_{bb}$ and their $P$-wave excited states has been systematically investigated. The production mechanism is that a color anti-triplet or sextuplet diquark $⟨Q{Q}^{\prime }⟩$ is first produced, and then evolved into a corresponding doubly heavy baryon ${\Xi }_{Q{Q}^{\prime }}$ via the subprocess $\gamma +\gamma \to ⟨Q{Q}^{\prime }⟩[n]+\overline{Q^{\prime }}+\bar{Q}\to {\Xi }_{Q{Q}^{\prime }}+\overline{Q^{\prime }}+\bar{Q}$. Here, $Q^{(\prime )}$ denotes the heavy quark $b$ or $c$, [$n$] is the color and spin quantum number of intermediate diquark, which can be ${[}^3{S}_1{]}_{\bar{\text{3}}/\text{6}}$ and ${[}^1{S}_0{]}_{\bar{\text{3}}/\text{6}}$ for $S$-wave states, or ${[}^1{P}_1{]}_{\bar{\text{3}}/\text{6}}$ and ${[}^3{P}_J{]}_{\bar{\text{3}}/\text{6}}$ with $J=0,1,2$ for $P$-wave states. Predictions for the cross sections, differential distributions, and theoretical uncertainty have been analyzed. The results indicate that, at $\sqrt{s}=91$ GeV, the contribution of photoproduction for $P$-wave ${\Xi }_{cc}$, ${\Xi }_{bc}$, and ${\Xi }_{bb}$ is approximately $2.19\%$, $4.23\%$, $1.26\%$ of the contribution for $S$-wave, respectively. As the collision energy increases, the contribution of $P$-wave also increases. Assuming that the highly excited state can decay into ground state with $100\%$ efficiency, the total produced events at CEPC and FCC-ee can be as high as $\mathcal{O}(10^8)$, $\mathcal{O}(10^7),$ and $\mathcal{O}(10^5)$ corresponding to ${\Xi }_{cc}$, ${\Xi }_{bc}$, and ${\Xi }_{bb}$, respectively, which is very promising to be detected in future experiments.

    hep-phJHEP(2025)·6 citations
33. 33*

    Higgs and Flavour: BSM Overview

    Joe Davighi🇨🇭

    We discuss scenarios for BSM physics near the TeV, motivated by the hierarchy problem and the flavour puzzle, and review their experimental tests at present and future colliders. Strong LHC constraints on couplings to light quarks motivate $U(2)$-like flavour symmetries as a means of lowering the new physics scale: this is demonstrated by general SMEFT analyses, and is also seen in composite Higgs solutions to the hierarchy problem. We discuss flavour non-universal gauge interactions as a possible origin for $U(2)$-like flavour symmetries which, in addition to allowing new physics to be lighter, opens up a simultaneous low-scale solution to the flavour puzzle. We focus on `flavour deconstructed' gauge interactions close to the TeV, and show how this non-universal gauge structure can be combined with Higgs compositeness in a way that better accommodates the requisite tuning in the Higgs mass.

    hep-ph2 citations
34. 34*

    Triply heavy tetraquark states in a mass-splitting model

    Shi-Yuan Li🇨🇳 · Yan-Rui Liu🇨🇳 · Zi-Long Man🇨🇳 · Cheng-Rui Shu🇨🇳 · Zong-Guo Si🇨🇳 · Jing Wu🇨🇳

    In a modified chromomagnetic interaction model, assuming $X(4140)$ to be the lowest $1^{++}$ $cs\bar{c}\bar{s}$ tetraquark and treating it as the reference state, we systematically investigated the masses of the triply-heavy tetraquark states $QQ\bar{Q}\bar{q}$ ($Q=c,b;q=u,d,s$). Because of their higher masses, no stable tetraquarks were found. Using a simple scheme, we also estimated the partial widths of the rearrangement decay channels and relevant ratios. A compact triply heavy tetraquark candidate would be favored if its observed mass and partial width ratios were comparable with our predictions. We hope that the present work will be helpful for further studies.

    hep-phhep-exhep-latSymmetry(2025)·7 citations
35. 35*

    Neutrino reheating predictions with non-thermal leptogenesis

    Xinyi Zhang🇨🇳

    Connecting inflation with neutrino physics through non-thermal leptogenesis via direct inflaton-right-handed neutrino (RHN) coupling naturally incorporates neutrino reheating, leaving no ambiguity regarding the early history of the Universe. In ref.~\cite{Zhang:2023oyo}, we demonstrate that non-thermal leptogenesis from inflaton decay expands the viable parameter space compared to thermal leptogenesis and provides a natural link to inflation. In this work, we refine our previous findings by closely examining the dynamics of neutrino reheating. We first calculate the duration of neutrino reheating on a general basis, then analyze inflationary observables consistent with neutrino reheating across four models, establishing a direct connection between baryon asymmetry and the spectral index. This approach places these two important observables on the same plane and yields specific predictions that help break the degeneracy among inflationary models. The well-motivated and economical framework offers a simple, natural, and testable description of the early Universe.

    hep-phastro-ph.COJHEP(2025)·1 citation
36. 36*

    Two-body Hidden Charm Decays of $D$ Wave Charmonia

    Xiao-Yu Qi🇨🇳 · Qi Wu🇨🇳 · Xing-Dao Guo🇨🇳 · Dian-Yong Chen🇨🇳

    The experimental observations of ${\psi }_2(3823)$ and ${\psi }_3(3842)$ make $D$ wave charmonia family abundant. In the present work, we investigate the hidden charm decay processes of spin triplets of the $D$-wave charmonia with the meson loop mechanism. The model parameter ${\alpha }_{\Lambda }$ is determined by reproducing the branching fraction of $\psi (3770)\to J/\psi \eta$. With this range of model parameter values, the branching fractions (partial widths) of $\psi (3770)\to {\eta }_c\omega$, ${\psi }_2(3823)/{\psi }_3(3842)\to J/\psi \eta$, ${\psi }_2(3823)/{\psi }_3(3842)\to {\eta }_c\omega$ are estimated. Our estimations find that the partial width of ${\psi }_2(3823)\to J/\psi \eta$ is $\left(29.64_{-4.63}^{+4.01}\right)\mathrm{keV}$, and the partial width ratio of ${\psi }_2(3823)\to J/\psi \eta$ relative to ${\psi }_2(3823)\to \gamma {\chi }_{c1}$ is about $10\%$, which could be tested by further precise measurements from the BESIII, Belle II and LHCb Collaborations.

    hep-phEPJC(2025)·5 citations
37. 37*

    Aspects of the dilute Glasma

    Markus Leuthner🇦🇹

    The Glasma is a semiclassical nonequilibrium state describing the earliest stage in relativistic heavy-ion collisions predicted by the Color Glass Condensate effective theory. It is characterized by strong color fields, which are sourced by color currents pertaining to hard partons in the colliding nuclei. We introduce the (3+1)D dilute Glasma framework, which incorporates the longitudinal and transverse structure of colliding particles and describes the rapidity-dependence of observables like the energy-momentum tensor. This is in stark contrast to the canonical picture of boost-invariance, where nuclei are infinitesimally thin in longitudinal direction, and the rapidity-dependence of observables is lost. We discuss the derivation of the (3+1)D dilute Glasma field-strength tensor, which relies on linearizing the Yang-Mills equations in the dilute approximation, i.e., assuming weak sources. The dilute Glasma energy-momentum tensor can efficiently be evaluated numerically on a lattice. Employing a generalized 3D McLerran-Venugopalan model, we discuss numerical results for the collisions of heavy ions at energies corresponding to experiments at RHIC and the LHC. We discover longitudinal flow that differs significantly from Bjorken flow and argue that this is a consequence of taking into account the longitudinal extension of nuclei. Furthermore, we find limiting fragmentation as a universal feature of the dilute Glasma analytically and numerically. Finally, we study the applicability of the dilute Glasma to proton-proton collisions and show the necessary modifications to reproduce experimental multiplicity distributions.

    hep-phnucl-th4 citations
38. 38*

    Mechanical properties of the nucleon from the generalized parton distributions

    The MMGPDs Collaboration · Muhammad Goharipour · Hadi Hashamipour · H. Fatehi · Fatemeh Irani · K. Azizi · S.V. Goloskokov

    The proton's internal structure is characterized not only by its charge and magnetic distribution but also by its mechanical and mass properties, which are encoded in the energy-momentum tensor (EMT) of quantum chromodynamics (QCD). These properties provide insights into the spatial distributions of energy, pressure, and shear forces within the proton. Understanding the proton's internal structure, including properties such as its mechanical and mass radii, is essential for unraveling the complex interplay between quarks and gluons that govern its stability and dynamics. In this study, we investigate the gravitational form factors (GFFs) of the proton, particularly the D-term, which encodes key information about the internal stress distribution, pressure, and shear forces within the nucleon. Using a model for skewness-dependent generalized parton distributions constructed from the double-distribution representation, we extract the quark contribution to the $D(t)$ GFF of the EMT by analyzing available data on Compton form factors. We then employ this extracted GFF to explore the mechanical properties of the proton, including its mechanical and mass radii, as well as the internal pressure and shear force distributions. Our results provide new insights into the proton's internal structure and contribute to the broader understanding of nucleon properties.

    hep-phhep-exhep-latPRD(2025)·33 citations
39. 39*

    Nucleon Form Factors from GPDs

    Leila Ghasemzadeh🇮🇷 · Pegah Sartipi YarAahmadi🇮🇷 · Fatemeh Arbabifar🇮🇷 · Nader Morshedian🇮🇷 · Shahin Atashbar Tehrani🇮🇷

    In this study, we introduce a novel ansatz for Generalized Parton Distributions (GPDs), named GSAMA24. This ansatz aims to provide a more accurate and comprehensive description of the internal structure of hadrons by incorporating advanced parameterizations and fitting techniques. We compare the performance of the GSAMA24 ansatz with three established models: the Extended Regge (ER), Modified Gaussian (MG), and M-HS22 ansatz. The GSAMA24 ansatz is designed to address limitations observed in previous models by offering improved flexibility in the ( $t$ )-dependence and skewness parameter $\xi$. Our analysis involves fitting the GSAMA24 ansatz to experimental form factor data and evaluating its predictive power against the ER, MG, and M-HS22 models. The comparison is based on key metrics such as the accuracy of form factor predictions, the consistency with known GPD properties, and the computational efficiency of the fitting process. Results indicate that the GSAMA24 ansatz provides a superior fit to the experimental data, particularly in the high momentum transfer region, where it outperforms the ER and MG models. Additionally, the GSAMA24 ansatz demonstrates better agreement with the theoretical expectations of GPD behavior compared to the M-HS22 model. These findings suggest that the GSAMA24 ansatz is a promising tool for future studies of hadronic structure and could significantly enhance our understanding of the spatial and momentum distributions of quarks and gluons within hadrons.

    hep-phPRC(2025)·2 citations
40. 40*

    Exclusive semileptonic decays of $D$ and $D_s$ mesons into orbitally and radially excited states of strange and light mesons

    V.O. Galkin🇷🇺 · I.S. Sukhanov🇷🇺

    Semileptonic decays of $D$ and $D_s$ mesons into orbitally and radially excited strange and light mesons are studied in detail within the framework of the relativistic quark model based on the quasipotential approach and quantum chromodynamics. The hadronic matrix elements of the weak current between meson states are calculated with the consistent account of relativistic effects including contributions of the intermediate negative energy states and boosts of the meson wave functions from the rest to moving reference frame. The invariant form factors that parameterize these matrix elements are obtained as the overlap integrals of the initial and final meson wave functions. Their dependence on the square of the transferred momentum $q^2$ is explicitly determined within the whole accessible kinematic range. A convenient analytical approximation for numerical values of form factors is given. These form factors and helicity formalism are employed for the calculation of the differential and total semileptonic decay rates of charm mesons into excited strange and light mesons. Different asymmetry and polarization parameters are also evaluated. The obtained results are compared with other theoretical calculations and available experimental data. Reasonable agreement with experimentally measured semileptonic decay branching fractions and upper bounds is obtained.

    hep-phhep-exPRD(2025)·8 citations
41. 41*

    Dynamic Neutrino Mass Ordering and Its Imprint on the Diffuse Supernova Neutrino Background

    Yuber F. Perez-Gonzalez🇪🇸 · Manibrata Sen🇮🇳

    Neutrino masses may have evolved dynamically throughout the history of the Universe, potentially leading to a mass spectrum distinct from the normal or inverted ordering observed today. While cosmological measurements constrain the total energy density of neutrinos, they are not directly sensitive to a dynamically changing mass ordering unless future surveys achieve exceptional precision in detecting the distinct imprints of each mass eigenstate on large-scale structures. In this work, we investigate the impact of a dynamic neutrino mass spectrum on the diffuse supernova neutrino background (DSNB), which is composed of neutrinos from all supernova explosions throughout cosmic history and is on the verge of experimental detection. The dynamic evolution of neutrino masses with redshift changes the propagation of neutrinos inside the supernova. Since neutrino oscillations are highly sensitive to the mass spectrum, we show that the electron neutrino survival probability carries distinct signatures of the evolving neutrino mass spectrum. Our results show that a dynamic neutrino mass spectrum can modify the DSNB flux in an energy-dependent way. However, we find that the current level of spectral shape uncertainty in DSNB modeling makes a direct detection beyond the reach of present and near-future experiments. Nonetheless, our study highlights the DSNB as a probe of redshift-dependent neutrino properties once the astrophysical systematics are brought under control.

    hep-phEPJC(2026)·4 citations
42. 42*

    Cosmological Consequences of Domain Walls Biased by Quantum Gravity

    Yann Gouttenoire🇮🇱 · Stephen F. King🇬🇧 · Rishav Roshan🇬🇧 · Xin Wang🇬🇧 · Graham White🇬🇧 · Masahito Yamazaki🇯🇵

    One of the simplest standard model extensions leading to a domain wall network is a real scalar $S$ with a $Z_2$ symmetry spontaneously broken during universe evolution. Motivated by the swampland program, we explore the possibility that quantum gravity effects are responsible for violation of the discrete symmetry, triggering the annihilation of the domain wall network. We explore the resulting cosmological implications in terms of dark radiation, dark matter, gravitational waves, primordial black holes, and wormholes connected to baby universes.

    hep-phastro-ph.COgr-qchep-thPRD(2025)·28 citations
43. 43*

    Theory of neutrino slow flavor evolution. Part II. Space-time evolution of linear instabilities

    Damiano F. G. Fiorillo🇩🇪 · Georg G. Raffelt🇩🇪

    Slow flavor evolution (defined as driven by neutrino masses and not necessarily ``slow'') is receiving fresh attention in the context of compact astrophysical environments. In Part~I of this series, we have studied the slow-mode dispersion relation following our recently developed analogy to plasma waves. The concept of resonance between flavor waves in the linear regime and propagating neutrinos is the defining feature of this approach. It is best motivated for weak instabilities, which probably is the most relevant regime in self-consistent astrophysical environments because these will try to eliminate the cause of instability. We here go beyond the dispersion relation alone (which by definition applies to infinite media) and consider the group velocities of unstable modes that determines whether the instability relaxes within the region where it first appears (absolute), or away from it (convective). We show that all weak instabilities are convective so that their further evolution is not local. Therefore, studying their consequences numerically in small boxes from given initial conditions may not always be appropriate.

    hep-phastro-ph.HEJHEP(2025)·28 citations
44. 44*

    Solving the strong CP problem

    Alessandro Strumia🇮🇹

    I briefly review solutions to the strong CP problem based on axions, parity invariance, CP-invariance, and present a new idea based on CP as part of a spontaneously broken flavour symmetry such as a U(1) or modular invariance.

    hep-phPoS(2025)·6 citations
45. 45*

    Normalizing Flow-Assisted Nested Sampling on Type-II Seesaw Model

    Rajneil Baruah🇮🇳 · Subhadeep Mondal🇮🇳 · Sunando Kumar Patra🇮🇳 · Satyajit Roy🇮🇳

    We propose a novel technique for sampling particle physics model parameter space. The main sampling method applied is Nested Sampling (NS), which is boosted by the application of multiple Machine Learning (ML) networks, e.g., Self-Normalizing Network (SNN) and Normalizing Flow (specifically RealNVP). We apply this on Type-II Seesaw model to test the efficacy of the algorithm. We present the results of our detailed Bayesian exploration of the model parameter space subjected to theoretical constraints and experimental data corresponding to the 125 GeV Higgs boson, $\rho$-parameter, and the oblique parameters. All associated data, figures, and trained ML models can be found here: https://github.com/sunandopatra/MLNS-T2SS

    hep-phEPJC(2025)·3 citations
46. 46*

    Effects of sub-nucleonic fluctuations on the longitudinal structure of heavy-ion collisions

    Oscar Garcia-Montero🇩🇪 · Sören Schlichting🇩🇪 · Jie Zhu🇨🇳

    Sub-nuclear fluctuations in the initial state of heavy-ion collisions impact not only transverse long-range correlations of small systems, but also the creation of longitudinal structures, seen in particle detectors as longitudinal decorrelation observables. In this work, we study the emergence of long-range rapidity correlations in nuclear collisions based on the 3D resolved McDIPPER initial state model, and for the first time, connect it to experimental observables using the 3+1D viscous hydrodynamics framework CLVisc. We include different sources of fluctuations at the nucleon and subnucleon level and study the effects of these additional fluctuation sources on the longitudinal structure of relevant observables, such as the flow decorrelations and directed flow.

    ↳ nucl-thhep-phPRD(2025)·12 citations
47. 47*

    The Double EFT Expansion in Quantum Gravity

    José Calderón-Infante🇨🇭 · Alberto Castellano🇺🇸 · Alvaro Herráez🇩🇪

    In this work, we aim to characterize the structure of higher-derivative corrections within low-energy Effective Field Theories (EFTs) arising from a UV-complete theory of quantum gravity. To this end, we use string theory as a laboratory and argue that such EFTs should exhibit a $\text{double EFT expansion}$ involving higher-curvature operators. The $\text{field-theoretic}$ expansion is governed by the mass of the lightest (tower of) new degrees of freedom, as expected from standard field theory considerations. Conversely, the $\text{quantum-gravitational}$ expansion is suppressed relative to the Einstein-Hilbert term by the quantum gravity cutoff, ${\Lambda }_{\mathrm{QG}}$, above which no local gravitational EFT description remains valid. This structure becomes manifest in the so-called $\text{asymptotic regime}$, where a hierarchy between the Planck scale and ${\Lambda }_{\mathrm{QG}}$ emerges, the latter identified herein as the species scale. Most notably, we demonstrate the features of the double EFT expansion through an amplitudes-based approach in (toroidal compactifications of) ten-dimensional Type IIA string theory, and via a detailed analysis of the supersymmetric black hole entropy in 4d $\mathcal{N}=2$ supergravities derived from Type II Calabi-Yau compactifications. We provide further evidence for our proposal across various string theory setups, including Calabi-Yau compactifications of M/F-theory and Type II string theory. Finally, we explore the implications of this framework for the Wilson coefficients of the aforementioned higher-curvature operators, revealing potentially significant constraints in the asymptotic regime and highlighting a remarkable interplay with recent results from the S-matrix bootstrap program.

    ↳ hep-thgr-qchep-phSciPost Phys.(2025)·40 citations
48. 48*

    Estimating the Black Hole Spin for the X-Ray Binary MAXI J1727-203 Based on Insight-HXMT

    Haifan Zhu · Wei Wang🇨🇳

    We constrain the spin of the black hole (BH) candidate MAXI J1727-203 using Insight-HXMT data. Due to limited HXMT observations covering only part of the outburst, NICER data were used to analyze the full outburst's state transitions, we identified two of three HXMT observations in the high soft state and applied the continuum-fitting method to measure the spin. Based on previous estimates and continuum spectral fittings, we explored the parameter space and found that the best-fitting values were $(D,i,M)\approx (6\text{kpc},30^{\circ },12M_{\odot })$. We also tested the variation of these parameters using Monte Carlo simulations, sampling over 3000 sets within the parameter ranges: $5.9\text{kpc}<D<7\text{kpc}$, $24^{\circ }<i<35^{\circ }$, and $10M_{\odot }<M<14M_{\odot }$, yielding a spin measurement of $a=0.34_{-0.19}^{+0.15}$ (1$\sigma$). In addition, we analyzed NuSTAR data in low hard state and found a good fit with the {\tt tbabs*(diskbb+powerlaw)} model, with no significant iron line features observed in the residuals, then the previous reflection model results suggesting an extremely high spin would over-estimate the BH spin.

    ↳ astro-ph.HEastro-ph.SRhep-phApJ(2025)·1 citation
49. 49*

    Elementary considerations on possible entropy-driven cosmological evolutions

    Jamy-Jayme Thézier🇫🇷 · Aurélien Barrau🇫🇷 · Killian Martineau🇫🇷

    For several independent reasons, the idea that notorious sources of entropy could exist in the Universe has been recently revived. Taking advantage of a new framework accounting for non-equilibrium processes in cosmology, we explicitly investigate the cosmological dynamics as a function of the entropy production, focusing on the stability of the system. An exhaustive investigation is performed. As the main physical conclusion, we show that for a wide class of entropy source terms, the fluid dynamics converges towards an effective cosmological constant. Constraints on the associated entropic force are also obtained.

    ↳ gr-qcastro-ph.COhep-phInt.J.Mod.Phys.D(2025)·0 citations
50. 50*

    Three-dimensional core-collapse supernova models with phenomenological treatment of neutrino flavor conversions

    Kanji Mori🇯🇵 · Tomoya Takiwaki🇯🇵 · Kei Kotake🇯🇵 · Shunsaku Horiuchi🇺🇸

    We perform three-dimensional supernova simulations with a phenomenological treatment of neutrino flavor conversions. We show that the explosion energy can increase to as high as ~10^51 erg depending on the critical density for the onset of flavor conversions, due to a significant enhancement of the mean energy of electron antineutrinos. Our results confirm previous studies showing such energetic explosions, but for the first time in three-dimensional configurations. In addition, we predict neutrino and gravitational wave (GW) signals from a nearby supernova explosion aided by flavor conversions. We find that the neutrino event number decreases because of the reduced flux of heavy-lepton neutrinos. In order to detect GWs, next-generation GW telescopes such as Cosmic Explorer and Einstein Telescope are needed even if the supernova event is located at the Galactic center. These findings show that the neutrino flavor conversions can significantly change supernova dynamics and highlight the importance of further studies on the quantum kinetic equations to determine the conditions of the conversions and their asymptotic states.

    ↳ astro-ph.HEastro-ph.SRhep-phPubl.Astron.Soc.Jap.(2025)·48 citations
51. 51*

    Novel Dark Matter Signatures

    A. Argiriou🇬🇷 · G. Cantatore🇮🇹 · S.A. Cetin🇹🇷 · E. Georgiopoulou🇬🇷 · D.H.H. Hoffmann🇨🇳 · S. Hofmann🇩🇪 · M. Karuza🇭🇷 · A. Kryemadhi🇺🇸 · M. Maroudas🇩🇪 · A. Mastronikolis🇬🇧 · E. L. Matteson · K. Özbozduman🇹🇷 and 7 other authors

    Celestial observations often exhibit inexplicable planetary dependencies when the timing of an observable is projected onto planetary heliocentric positions. This is possible only for incident, non-relativistic streams. Notably, the celebrated dark matter (DM) in the Universe can form streams in our vicinity with speeds of about 240 km/s. Since gravitational impact scales with $1/(\text{velocity}{)}^2$, all solar system objects, including the Sun and the Moon, act as strong gravitational lenses, with their focal planes located within the solar system. Even the Moon can focus penetrating particles toward the Earth at speeds of up to approximately 400 km/s, covering a large portion of the phase space of DM constituents. Consequently, the unexpected planetary dependencies of solar system observables may provide an alternative to Zwicky's tension regarding the overestimated visible cosmic mass. In this work, an overlooked but unexpected planetary dependency of any local observable serves as an analogue to Zwicky's cosmic measurements, particularly if a similar mysterious behavior has been previously noted. Thus, a persistent, unexpected planetary dependency represents a new tension between observation and expectation. The primary argument supporting DM in line with Zwicky's paradigm is this planetary dependency, which, on a local scale, constitutes the novel tension between observation and expectation. In particular, the recurrent planetary dependency of diverse observables mirrors Zwicky's cosmic tension with the overestimated visible mass. No other approach accounts for so many otherwise striking and mysterious observations in physics and medicine.

    ↳ astro-ph.EPastro-ph.IMastro-ph.SRgr-qc+2PoS(2025)·5 citations
52. 52*

    Imaging nuclei by smashing them at high energies: how are their shapes revealed after destruction?

    Jiangyong Jia🇺🇸

    High-energy nuclear collisions have recently emerged as a promising ``imaging-by-smashing'' approach that may reveal the intrinsic shapes of atomic nuclei. Here, I outline a conceptual framework for this technique, explaining how nuclear shapes are encoded during quark-gluon plasma formation and evolution, and how they can be decoded from final-state particle distributions. I highlight the method's potential to advance our understanding of both nuclear structure and quark-gluon plasma physics.

    ↳ nucl-thhep-phnucl-exphysics.atm-clus+1Rept.Prog.Phys.(2025)·14 citations
53. 53*

    Gamma rays from star clusters and implications for the origin of Galactic cosmic rays

    Pasquale Blasi (GSSI)🇮🇹

    Context. Star clusters are often invoked as contributors to the flux of Galactic cosmic rays and as sources potentially able to accelerate particles to $\sim$PeV energies. The gamma radiation with $E\gtrsim$ TeV recently observed from selected star clusters has profound implications for the origin of Galactic cosmic rays. Aims. We show that if the gamma rays observed from the Cygnus cocoon and Westerlund 1 are of hadronic origin, then the cosmic rays escaping the cluster at energies $\gtrsim$ 10 TeV must cross a grammage inside the cluster that exceeds the Galactic grammage. At lower energies, depending on the model adopted to describe the production of gamma rays, such grammage may exceed or be comparable with the grammage inferred from propagation on Galactic scales. Methods. The flux of gamma rays is analytically computed for a few models of injection of cosmic rays in star clusters, and compared with the flux measured from selected clusters. Results. In all models considered here, comparing the inferred and observed gamma ray fluxes at $E\gtrsim$ TeV, we conclude that CRs must traverse a large grammage inside or around the cluster before escaping. Clearly these implications would not apply to a scenario in which gamma rays are produced due to radiative losses of leptons in the cluster. Leptonic models typically require weaker magnetic fields, which in turn result in maximum energies of accelerated particles much below $\sim$ PeV. Conclusions. We conclude that if gamma ray emission in SCs is a generic phenomenon and if this radiation is due to hadronic interactions, either star clusters cannot contribute but a small fraction of the total cosmic ray flux at the Earth, or their contribution to the grammage cannot be neglected and the paradigm of Galactic transport should be profoundly revisited.

    ↳ astro-ph.HEhep-phAstron.Astrophys.(2025)·11 citations
54. 54*

    TOP2024: an overview of experimental results

    Abideh Jafari🇮🇷

    The $17^{\text{th}}$ edition of the international workshop on top quark physics featured a diverse set of outstanding results. This note is an attempt to summarize the workshop from the experimental perspective and suggest ways forward for the future investigations. As it has not been possible to touch upon every single physics analysis in this note, interested reader are referred to individual proceedings for details.

    ↳ hep-exhep-phSciPost Phys.Proc.(2026)·5 citations
55. 55*

    Geometrical origin of inflation in Weyl-invariant Einstein-Cartan gravity

    Georgios K. Karananas🇩🇪

    It is shown that the scalar degree of freedom built-in in the quadratic Weyl-invariant Einstein-Cartan gravity can drive inflation and with predictions in excellent agreement with observations.

    ↳ gr-qcastro-ph.COhep-phPLB(2025)·18 citations
56. 56*

    Greybody factors, reflectionless scattering modes, and echoes of ultracompact horizonless objects

    Romeo Felice Rosato🇮🇹 · Shauvik Biswas🇮🇳 · Sumanta Chakraborty🇮🇳 · Paolo Pani🇮🇹

    Motivated by a recently discovered connection between the greybody factors of black holes and the ringdown signal, we investigate the greybody factors of ultracompact horizonless objects, also elucidating their connection to echoes. The greybody factor of ultracompact objects features both low-frequency resonances and high-frequency, quasi-reflectionless scattering modes, which become purely reflectionless in the presence of symmetric cavity potentials, as it might be the case for a wormhole. We show that it is these high-frequency (quasi-)reflectionless scattering modes, rather than low-frequency resonances, to be directly responsible for the echoes in the time-domain response of ultracompact objects or of black holes surrounded by matter fields localized at large distances.

    ↳ gr-qcastro-ph.HEhep-phPRD(2025)·43 citations
57. 57*

    Relativistic chiral nuclear forces: status and prospects

    Jun-Xu Lu🇨🇳 · Yang Xiao🇨🇳 · Zhi-Wei Liu🇨🇳 · Li-Sheng Geng🇨🇳

    Understanding nuclear structure, reactions, and the properties of neutron stars from \textit{ab initio} calculations from the nucleon degrees of freedom has always been a primary goal of nuclear physics, in which the microscopic nuclear force serves as the fundamental input. So far, the Weinberg chiral nuclear force, first proposed by the Nobel laureate Weinberg, has become the \textit{de facto} standard input for nuclear \textit{ab initio} studies. However, compared to their non-relativistic counterparts, relativistic \textit{ab initio} calculations, which describe better nuclear observables, have only begun. The lack of modern relativistic nucleon-nucleon interactions is an important issue restricting their development. In this work, we briefly review the development and status of the Weinberg chiral nuclear force, as well as its limitations. We further present a concise introduction to the relativistic chiral nuclear force, show its description of the scattering phase shifts and observables such as differential cross sections, and demonstrate its unique features. Additionally, we show that the relativistic framework could be naturally extended to the antinucleon-nucleon interaction.

    ↳ nucl-thhep-lathep-phnucl-exIJMPE(2025)·10 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.