Tue·Mar 4, 2025Tuesday·March 4, 2025

1. 01*

   Probing Superheavy Dark Matter with Exoplanets

   Mehrdad Phoroutan-Mehr🇺🇸 · Tara Fetherolf🇺🇸

   Exoplanets, with their large volumes and low temperatures, are ideal celestial detectors for probing dark matter (DM) interactions. DM particles can lose energy through scattering with the planetary interior and become gravitationally captured if their interaction with the visible sector is sufficiently strong. In the absence of annihilation, the captured DM thermalizes and accumulates at the planet's center, eventually collapsing into black holes (BH). Using gaseous exoplanets as an example, we demonstrate that BH formation can occur within an observable timescale for superheavy DM with masses greater than $10^6\mathrm{GeV}$ and nuclear scattering cross sections. The BHs may either accrete the planetary medium or evaporate via Hawking radiation, depending on the mass of the DM that formed them. We explore the possibility of periodic BH formation within the unconstrained DM parameter space and discuss potential detection methods, including observations of planetary-mass objects, pulsed high-energy cosmic rays, and variations in exoplanet temperatures. Our findings suggest that future extensive exoplanet observations could provide complementary opportunities to terrestrial and cosmological searches for superheavy DM.

   hep-phPRD(2025)·7 citations
2. 02*

   Dynamical Scaling in Pair Production for Scalar QED

   Deepak Sah🇮🇳 · Manoranjan P. Singh🇮🇳

   We report on the dynamical scaling of momentum spectra for particle-antiparticle pairs at finite times within the framework of scalar Quantum Electrodynamics (QED). The analysis focuses on the momentum spectra in two different choices of adiabatic mode functions, which are related by a Wronskian normalization condition. Oscillations in the momentum spectra are attributed to quantum interference effects in the adiabatic number basis. A novel dynamical scaling behavior emerges when examining the oscillatory momentum spectra of pairs created by a Sauter pulsed field at intermediate times. While the oscillatory spectra are observed at distinct times in the two different choices, they overlap when time is rescaled by the point marking the initiation of the first occurrence of the Residual ParticleAntiparticle Plasma (RPAP) stage (or end of the transient stage) for the central momentum case. This scaling identifies the approximate time at which real particle-antiparticle pair formation becomes possible, shifting the focus from asymptotic times to finite-time dynamics. Additionally, in the multi-photon regime, we find that the momentum spectra exhibit a multi-modal profile structure at finite times, consistent across both choices and also follow the dynamical scaling in this case as well.

   hep-phphysics.plasm-phPhys.Scripta(2025)·1 citation
3. 03*

   One-loop off-shell quark-gluon vertex in arbitrary gauge and dimensions: a streamlined approach through the second-order formalism of QCD

   Victor Miguel Banda Guzmán🇲🇽 · Adnan Bashir🇲🇽

   The standard Feynman rules used for perturbative calculations in quantum chromodynamics (QCD) are derived from a Lagrangian that is first-order in derivatives. It includes a three-point quark-gluon vertex which obscures the precise disentangled manner in which spin and momentum are interchanged during these interactions. An unambiguous understanding of this interchange is insightful for efficiently extracting physically relevant information from various Green's functions. To separate the scalar and spin degrees of freedom and gain physical insight from the outset, we examine the quark-gluon vertex using the less commonly employed second-order formalism of QCD. We compute this off-shell vertex in arbitrary space-time dimensions and covariant gauges by using scalar integrals with shifted dimensions, which include higher powers of the propagators, within a combined first- and second-order formalism. This approach naturally identifies the transverse components of the quark-gluon vertex, even before evaluating the tensor Feynman integrals. We also compute the on-shell version of this vertex using exclusively the second-order formalism, facilitating a precise identification of spin and momentum interchange. Through analyzing the Pauli form factor at $k^2=0$ (where $k$ represents the momentum of the external gluon), we find that only a specific set of second-order Feynman diagrams are relevant for calculating the electromagnetic and chromomagnetic dipole moments. These diagrams represent quantum processes in which the spin of the incoming quark changes only once due to interactions with the virtual gluons that form the quark-gluon vertex. All other interactions involve only momentum interchange (scalar interactions). Our results are in complete agreement with those obtained from the first-order formalism.

   hep-phhep-thnucl-thPRD(2025)·2 citations
4. 04*

   A Comprehensive Framework for Electroweak Phase Transitions: Thermal History and Dynamics from Bubble Nucleation to Percolation

   Haibin Chen🇨🇳 · Yun Jiang🇨🇳

   The electroweak phase transition (EWPT) is crucial for cosmology and particle physics, with a profound impact on electroweak baryogenesis, symmetry breaking, and gravitational wave (GW) signals. However, many studies overlook key aspects of EWPT dynamics, leading to misidentified patterns and overestimated GW signals. To address these gaps, we present a comprehensive framework for analyzing EWPTs, focusing on the vacuum's thermal history and dynamics from bubble nucleation to percolation. Using the ${\mathbb{Z}}_2$-odd real scalar singlet model, we demonstrate the occurrence of spontaneous ${\mathbb{Z}}_2$ symmetry breaking in the high-temperature vacuum, leading to diverse EWPT processes, including multi-step transitions and inverse symmetry breaking. We identify four distinct EWPT patterns, each characterized by unique symmetry-breaking mechanisms and associated with bubbles exhibiting distinct field configurations, which can be analyzed using a formalism based on energy density distributions developed here. A key finding is that bubble nucleation fails in extremely strong phase transitions (PTs) with low nucleation rates, or in ultra-fast PTs involving inverse $s$-bubbles that collapse instantly upon formation, both of which lead to false vacuum trapping and the absence of observable GW signals. In first-order PTs where nucleation succeeds, stronger transitions occur later in the universe's evolution, while weaker transitions proceed more rapidly. Multi-step transitions involving (inverse) ${\mathbb{Z}}_2$ symmetry breaking give rise to complex transition sequences and exotic bubble dynamics, such as sequential nucleation or the coexistence of bubbles from different vacua -- phenomena with significant implications for GW spectra, dark matter, and baryogenesis. This work advances our understanding of EWPT dynamics and lays the groundwork for future studies of EWPTs in BSM physics.

   hep-ph7 citations
5. 05*

   The $B^{-}\to J/\psi {\eta }^{\prime }{K}^{-}$ reaction and the $Y(4710)$ and $K_0^{\ast }(1430)$ contributions

   Wen-Tao Lyu🇨🇳 · Man-Yu Duan🇨🇳 · De-Min Li🇨🇳 · Bing Wang🇨🇳 · Dian-Yong Chen🇨🇳 · En Wang🇨🇳

   Motivated by the recent LHCb Collaboration analysis, we have investigated the process $B^{-}\to J/\psi {\eta }^{\prime }{K}^{-}$ by considering the contributions from the resonances $Y(4710)$ and $K_0^{\ast }(1430)$. Our results are in good agreement with the measured invariant mass distributions and the Dalitz plot of LHCb, which supports the existence of the $K_0^{\ast }(1430)$ and the $Y(4710)$ in the process $B^{-}\to J/\psi {\eta }^{\prime }{K}^{-}$. Since the decay mode of $Y(4710)\to J/\psi {\eta }^{\prime }$ is Okubo-Zweig-Iizuka (OZI) suppressed for the charmonium state, the measurements of the $\mathcal{B}(Y(4710)\to J/\psi {\eta }^{\prime })$ through the process $B^{-}\to J/\psi {\eta }^{\prime }{K}^{-}$ or other processes is helpful to understanding the nature of the $Y(4710)$. Thus, we advocate that Belle~II and LHCb Collaborations could perform the more precise analysis to confirm the evidence of the $Y(4710)$ state, which could be helpful to reduce the experimental uncertainties of its mass and width, and to explore its nature.

   hep-phPRD(2025)·1 citation
6. 06*

   Does $f_1(1420)$ have a double-peak structure?

   Bao-Xi Sun🇨🇳

   The one-pion exchange interaction between the kaon and the vector antikaon is investigated by solving the Schrodinger equation in the S-wave approximation. In addition to the $f_1(1285)$ particle, another bound state of $K{\bar{K}}^{\ast }$ is found, which is approximately 9 MeV below the threshold of $K{\bar{K}}^{\ast }$ and labeled $f_1(1378)$ for convenience in this manuscript. Under the outgoing wave condition, two resonance states of $K{\bar{K}}^{\ast }$ are produced by solving the Schrodinger equation with different coupling constants in the one-pion-exchange potential fixed with the binding energies of $K{\bar{K}}^{\ast }$ bound states $f_1(1285)$ and $f_1(1378)$ respectively. Both of the resonance states are located in the vicinity of 1400 MeV, and thus it is reasonable to assume that these two resonance states correspond to the $f_1(1420)$ particle in the review of the Particle Data Group although they arise from different couplings of the kaon and vector antikaon, respectively.

   hep-phnucl-th0 citations
7. 07*

   Threshold resummation for $ZZ$ production

   Pulak Banerjee🇮🇹

   We briefly review the status of threshold resummation for two massive $Z$-bosons in the Standard Model. We discuss some recent results for $Z$-boson pair production at next-to-next-to-leading order + next-to-next-to-leading logarithmic accuracy.

   hep-phEur.Phys.J.ST(2026)·1 citation
8. 08*

   Study of $1^{--}$ P wave charmoniumlike and bottomoniumlike tetraquark spectroscopy

   Zheng Zhao🇹🇭 · Attaphon Kaewsnod🇹🇭 · Kai Xu🇹🇭 · Nattapat Tagsinsit🇹🇭 · Xuyang Liu🇹🇭 · Ayut Limphirat🇹🇭 · Yupeng Yan🇹🇭

   The masses of $1^{--}$ P-wave charmonium-like and bottomonium-like tetraquark states are calculated in a constituent quark model (CQM) where the Cornell-like potential and Breit-Fermi interaction are employed. All model parameters were imported from previous work, and predetermined by studying the low-lying conventional S- and P-wave light, charmed, bottom, charmonium, and bottomonium meson mass spectra. The lowest $1^{--}$ tetraquark mass is predicted to be around 4.15 GeV. The decay widths of $1^{--}$ P-wave tetraquark states are calculated for possible two-body strong decay channels within the rearrangement mechanism, including $\omega {\chi }_{cJ}$ and $\eta J/\psi$ for charmonium-like tetraquarks, and $\omega {\chi }_{bJ}$ for bottomonium-like tetraquarks. The theoretical results are compared with the selected exotic states, also known as Y states, and tentative assignments are suggested. This study suggests that $\psi (4230)$, $\psi (4360)$, $\psi (4660)$, and ${\rm Y}$(10753) may be P-wave tetraquark states and that multiple states might exist around 4.36 GeV.

   hep-ph9 citations
9. 09*

   Possible Explanation of $F_2^n/F_2^p$ at Large $x$ Using Quantum Statistical Mechanics

   C. Bourrely🇫🇷 · F. Buccella🇮🇹 · W. C. Chang🇹🇼 · D. Di Bari🇮🇹 · P. H. Frampton🇮🇹 · J. C. Peng🇺🇸

   The recent accurate measurements of the scattering of electrons off of the mirror nuclei ${}^3$H and ${}^3$He show with small errors that the neutron to proton ratio $r(x)=F_2^n(x)/F_2^p(x)$, approaches a value larger than 1/4 for $x\to 1$. We suggest a possible explanation for this experimental result by studying the consequences of the Pauli exclusion principle for the parton distribution when the ratio is described by quantum statistical mechanics description in terms of three parameters inspired by the quantum statistical approach.

   hep-phnucl-thNPA(2026)·1 citation
10. 10*

    The $J/\psi$-nucleon interaction mechanism: A theoretical study based on scattering length

    Bing Wu🇨🇳 · Xiang-Kun Dong🇩🇪 · Meng-Lin Du🇨🇳 · Feng-Kun Guo🇨🇳 · Bing-Song Zou🇨🇳

    The low-energy $J/\psi N$ scattering is of significant importance for various reasons. It is deeply interconnected with the hidden-charm $P_c$ pentaquark states, provides insights into the role of gluons in nucleon structures, and is pertinent to the properties of $J/\psi$ in nuclear medium. The scattering can occur through two distinct mechanisms: the coupled-channel mechanism involving open-charm meson-baryon intermediate states ${\Lambda }_c{\bar{D}}^{(\ast )}$ and ${\Sigma }_c^{(\ast )}{\bar{D}}^{(\ast )}$, and the soft-gluon exchange mechanism. In this study, we investigate the $S$-wave $J/\psi N$ scattering length arising from both mechanisms. Our findings indicate that both mechanisms lead to attractive interactions, yielding scattering lengths of $[-10,-0.1]\times 10^{-3}$ fm for the coupled-channel mechanism and $<-0.16$ fm for the soft-gluon exchange mechanism, respectively. Notably, the soft-gluon exchange mechanism produces a scattering length that is at least one order of magnitude larger than that from the coupled-channel mechanism, indicating its predominance. These findings can be corroborated through lattice calculations and will enhance our understanding of scattering processes that violate the Okubo-Zweig-Iizuka rule.

    hep-phPoS(2026)·1 citation
11. 11*

    Matching the real Higgs triplet extension of Standard Model to HEFT

    Huayang Song🇰🇷 · Xia Wan🇨🇳

    We make a first matching of the real Higgs triplet extension (RHTE) of the standard model to the Higgs effective field theory (HEFT), which is also known as electroweak chiral Lagrangian (EWChL). In the RHTE, the ratio $\xi$ of two VEVs separately from triplet and doublet is a tiny quantity, due to the constrained custodial symmetry violation. Based on the nonlinear representation~\cite{Song:2024kos} of RHTE and functional method, we get the HEFT in the power counting of $\xi$. By comparing its phenomenological results of $hh\to hh$, $WW\to hh$, $ZZ\to hh$ to SMEFT's, we show its convergence property is as good as SMEFT's. Besides we explicitly show that the HEFT is available in the phase transition region where SMEFT fails.

    hep-phJHEP(2025)·9 citations
12. 12*

    Time-evolution of parity-odd cascades in homogeneous Abelian and non-Abelian media with chiral imbalance

    Jeremy Hansen🇺🇸 · Kirill Tuchin🇺🇸

    We study radiation by a fast particle in a medium with a finite chiral chemical potential. The medium's anomalous response encompasses the chiral magnetic effect, enabling novel chiral Cherenkov and pair production processes. The kinematics of the corresponding cascades is fundamentally different from conventional cascades. Notably, it is not dominated by the strong ordering of momenta. Employing the effective Chern-Simons extensions of QED and QCD to incorporate the chiral magnetic effect, we derive and solve the evolution equations describing the cascades in a chiral medium, presuming that the anomalous contributions are dominant.

    hep-phhep-thnucl-thPRD(2025)·5 citations
13. 13*

    Exploring fully-heavy tetraquarks through the CGAN framework: Mass and width

    M. Malekhosseini🇮🇷 · S. Rostami🇮🇷 · A. R. Olamaei🇮🇷 · K. Azizi🇮🇷

    Fully-heavy tetraquark states, $QQ\bar{Q}\bar{Q}(Q=c,b)$, have garnered significant attention both experimentally and theoretically, due to their unique properties and potential to provide new insights into Quantum Chromodynamics (QCD). In this study, we employ Conditional Generative Adversarial Networks (CGANs) to predict the masses and decay widths of fully-heavy tetraquarks. To deepen our understanding of heavy multiquark structures, we prepare datasets based on two distinct approaches and train the CGAN model using both. The CGAN framework allows us to capture the complex relationships between input features, such as quark content, quantum numbers, and Clebsch-Gordan coefficients, and output properties, including mass and decay width. Our predictions, based on the CGAN framework, are consistent with existing data. By combining fundamental knowledge of QCD with advanced machine learning techniques, this work represents a significant step forward in the theoretical understanding of fully-heavy tetraquark states. Our CGAN approach has the potential to become a strong contender for future studies in heavy tetraquark systems, complementing existing theoretical models to deliver more precise results. Additionally, our findings could assist in the search for fully-heavy tetraquark systems in future experiments.

    hep-phhep-exhep-latNPB(2025)·8 citations
14. 14*

    The Role of the Schwinger Effect in Superradiant Axion Lasers

    Bradley Shapiro🇺🇸

    Superradiance can cause the axion cloud around a rotating black hole to reach extremely high densities, and the decay of these axions can produce a powerful laser. The electric field of these lasers is strong enough that the Schwinger effect may become significant, resulting in the production of an electron-positron plasma. We explore the dynamics between axion lasers and this electron-positron plasma. While there are several mechanisms by which the inclusion of a plasma can impact the laser's behavior, the most significant of these mechanisms is that the electron-positron plasma imparts an effective mass on the photon. As the plasma frequency increases, axion decay becomes energetically unfavorable, up to the point where the axion no longer decays into photons, shutting off the laser. We find that the impact of the electron-positron plasma on the dynamics of the system depend heavily on the parameters, specifically the axion mass $m_{\varphi }$ and the superradiant coupling $\alpha$, and that we may divide parameter space into three regimes: the unenhanced, enhanced, and unstable regimes. In the unenhanced and enhanced regime, the system will eventually settle into an equilibrium state, emitting a laser of constant luminosity while the number of axions remains constant. In the unenhanced regime, this equilibrium state can be calculated while neglecting the effects of Schwinger production; in the enhanced regime, the equilibrium luminosity is slightly larger than what it would be without Schwinger production. In the unstable regime, the electron-positron plasma suppresses axion decay to the point where the system is never able to reach equilibrium; instead, the axions continue to grow superradiantly. In all three cases, the production of superradiant axions will eventually cause the black hole to spin down to the point where superradiance ceases.

    hep-phastro-ph.HEgr-qchep-thPRD(2025)·2 citations
15. 15*

    General behavior of near-threshold hadron scattering for exotic hadrons

    Katsuyoshi Sone🇯🇵 · Tetsuo Hyodo🇯🇵

    We discuss the general behavior of the near-threshold scattering amplitude with channel couplings. The signal of the exotic hadrons near the threshold may manifest as a dip structure in the cross section originated from a zero point of the scattering amplitude. Such a dip structure by the zero point cannot be reproduced by the Flatté amplitude which is widely used for the analysis of exotic hadrons, because of the constraints imposed on the Flatté amplitude near the threshold. In this work, we propose the General amplitude which can describe the dip structure near the threshold, in contrast to the Flatté amplitude. Moreover, we numerically study the behavior of the near-threshold cross section in relation to the zero point.

    hep-phnucl-thPoS(2025)·0 citations
16. 16*

    Effects of Initial Nucleon-Nucleon Correlations on Light Nuclei Production in Au+Au Collisions at $\sqrt{s_{\mathrm{NN}}}=3$ GeV

    Qian-Ru Lin🇨🇳 · Yu-Jing Huang🇨🇳 · Long-Gang Pang🇨🇳 · Xiao-Feng Luo🇨🇳 · Xin-Nian Wang🇨🇳

    Light nuclei production in heavy-ion collisions serves as a sensitive probe of the QCD phase structure. In coalescence models, triton ($N_t$) and deuteron ($N_d$) yields depend on the spatial separation of nucleon pairs ($\Delta r$) in Wigner functions, yet the impact of initial two-nucleon correlations $\rho (\Delta r)$ remains underexplored. We develop a method to sample nucleons in ${}^{197}$Au nuclei that simultaneously satisfies both the single-particle distribution $f(r)$ and the two-nucleon correlation $\rho (\Delta r)$. Using these nuclei, we simulate Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=3$ GeV via the SMASH transport model (mean-field mode) to calculate proton, deuteron, and triton yields. Simulations reveal a 36% enhancement in mid-rapidity deuteron yields across all centrality ranges and a 33% rise in mid-rapidity triton production for 0-10% central collisions. Calculated transverse momentum of light nuclei aligns with STAR data. We further analyze impacts of baryon conservation, spectator exclusion, and centrality determination via charged multiplicity. Notably, observed discrepancies in the double yield ratio suggest unaccounted physical mechanisms, such as critical fluctuations or inaccuracies in coalescence parameters or light nuclei cross-sections. This underscores the critical role of initial nucleon-nucleon correlations, linking microscopic nuclear structure to intermediate-energy collision dynamics.

    hep-phnucl-th4 citations
17. 17*

    Reheating after Axion Inflation

    Tomohiro Fujita🇯🇵 · Kyohei Mukaida🇯🇵 · Tenta Tsuji🇯🇵

    We investigate the reheating process in an axion inflation model where the inflaton couples to non-Abelian gauge fields via the Chern-Simons coupling. The Chern-Simons coupling leads to the efficient production of gauge fields via a tachyonic instability during inflation, whose implications have been actively studied in the literatures. Moreover, it has been recently pointed out that the produced gauge fields can be even thermalized during inflation, leading to warm inflation. Apparently, these findings seem to imply that the reheating is completed immediately after inflation because the tachyonic instability or the thermal friction induced by the Chern-Simons coupling cause the inflaton condensate to decay rapidly. Contrary to this naive expectation, however, we show that, in most of the parameter space, either the inflaton condensate, the inflaton particles, or the glueballs once dominate the Universe and their perturbative decay completes the reheating.

    hep-phastro-ph.COJCAP(2025)·10 citations
18. 18*

    Mass spectra of singly heavy baryons in the relativized quark model with heavy-quark dominance

    Zhen-Yu Li🇨🇳 · Guo-Liang Yu🇨🇳 · Zhi-Gang Wang🇨🇳 · Jian-Zhong Gu🇨🇳 · Hong-Tao Shen🇨🇳

    The rigorous calculation of the spin-orbit terms in the three-quark system is realized based on the Gaussian expansion method and the infinitesimally-shifted Gaussian basis functions in the frame work of the relativized quark model, by ignoring the mixing between different excited states. Then, the complete mass spectra of the singly heavy baryons are obtained rigorously, under the mechanism of the heavy-quark dominance. On these bases, the systematical analyses are carried out for the reliability and predictive power of the model, the fine structure of the singly heavy baryon spectra, the assignments of the excited baryons, and some important topics about the heavy baryon spectroscopy such as the missing states, the `spin-orbit puzzle', the clustering effect, etc. The result confirms that under the heavy-quark dominance mechanism, the relativized quark model can describe the excitation spectra and the fine structures of the singly heavy baryons correctly and precisely.

    hep-phCPC(2025)·7 citations
19. 19*

    Role of the short-range dynamics in the formation of $D^{(\ast )}{\bar{D}}^{(\ast )}/B^{(\ast )}{\bar{B}}^{(\ast )}$ hadronic molecules

    Nijiati Yalikun🇨🇳 · Xiang-Kun Dong🇩🇪 · Ulf-G. Meißner🇩🇪

    We investigate potential hadronic molecular states in the $D^{(\ast )}{\bar{D}}^{(\ast )}$ and $B^{(\ast )}{\bar{B}}^{\ast }$ systems using light meson exchange interactions. Our analysis focuses on coupled-channel systems with spin-parity quantum numbers $J^{PC}=0^{++}$, $1^{+\pm }$ and $2^{++}$, examining how the $\delta (r)$ potential affects states near threshold. Using coupled-channel analysis, we reproduce the $X(3872)$ mass with a given cutoff for the $(I)J^{PC}=(0)1^{++}$ state, finding a minimal impact from the $\delta (r)$ term. At this cutoff, both the $(0)0^{++}$ state near the $D\bar{D}$ threshold and the $(0)1^{+-}$ state near the $D{\bar{D}}^{\ast }$ threshold show less sensitivity to the $\delta (r)$ term compared to the three states-$(0)0^{++}$, $(0)1^{+-}$, and $(0)2^{++}$-near the $D^{\ast }{\bar{D}}^{\ast }$ threshold. As anticipated, the $B^{(\ast )}{\bar{B}}^{\ast }$ systems exhibit similar behavior but with stronger binding due to their larger reduced mass. These findings suggest promising directions for future experimental searches, particularly in the isoscalar sector, which could substantially advance our understanding of exotic tetraquark states.

    hep-phnucl-thPRD(2025)·11 citations
20. 20*

    Formation of true muonium in the Drell-Yan dimuon production

    Sergei N. Gninenko🇷🇺 · Sergey Kuleshov🇨🇱 · Valery E. Lyubovitskij🇨🇱 · Alexey S. Zhevlakov🇷🇺

    We suggest a new mechanism for the formation of true muonium ($TM$), the QED $({\mu }^{+}{\mu }^{-})$ bound state, due to the Coulomb interaction of muons from ${\mu }^{+}{\mu }^{-}$ pairs generated in the Drell-Yan reaction of protons off nuclei of a thin foil target. The $TM$ atoms produced in the ${}^3{S}_1$ long-lived triplet state ($oTM$) could escape from the foil to vacuum followed by their decay into $e^{+}{e}^{-}$ pairs. Observation of $e^{+}{e}^{-}$ events with a displaced vertex, and an invariant mass and decay time consistent with the mass and lifetime of the $oTM$ is used as a signature of the discovery of $TM$. We present estimates of the $TM$ yield and briefly discuss an experiment which could lead to such a discovery.

    hep-ph3 citations
21. 21*

    Global Neutrino Constraints on the Minimal U(1)${}_{L_{\mu }-L_{\tau }}$ Model

    Masahiro Ibe🇯🇵 · Satoshi Shirai🇯🇵 · Keiichi Watanabe🇯🇵

    We examine the minimal U(1)${}_{L_{\mu }-L_{\tau }}$ gauge model in light of the latest neutrino data, including neutrino oscillations, cosmological observations, direct mass measurements, and neutrinoless double-beta decay. Using the most conservative oscillation data, we find that normal ordering is excluded at approximately the 90% confidence level (CL). Incorporating cosmological constraints from Cosmic Microwave Background (CMB) observations strengthens this exclusion to about 95% CL, while further including Baryon Acoustic Oscillation (BAO) data increases it to nearly 99% CL. The inverted ordering is even more strongly disfavored. Our analysis is performed within a frequentist framework, minimizing sensitivity to prior assumptions inherent in Bayesian approaches. These results impose strong constraints on the viability of the minimal U(1)${}_{L_{\mu }-L_{\tau }}$ gauge model.

    hep-phPRD(2025)·6 citations
22. 22*

    Spectral Analysis and Decay Mechanisms of $1^{-+}$ Hybrid States in Light Meson Sector

    Fu-Yuan Zhang🇨🇳 · Qi Huang🇨🇳 · Li-Ming Wang🇨🇳

    The exploration of exotic mesons, which transcend the conventional quark-antiquark framework, is pivotal for advancing our understanding of QCD and the strong interaction. Among these, states possessing the quantum numbers $J^{PC}=1^{-+}$, such as ${\pi }_1(1600)$, ${\pi }_1(2015)$, and the recently discovered ${\eta }_1(1855)$, have attracted significant attention due to their potential hybrid nature, which involves gluonic excitations. However, the physical interpretation of these states remains contentious, primarily due to inconsistencies between theoretical predictions and experimental observations regarding their decay widths and mass spectra. To address these challenges, we employ a potential model inspired by SU$(3)$ lattice gauge theory to calculate the masses of light-flavor $1^{-+}$ hybrid states and utilize the constituent gluon model to analyze their strong decay properties. Our mass calculations suggest that while the ${\pi }_1(1600)$ and ${\eta }_1(1855)$ masses are in close agreement with the predicted hybrid states, the corresponding decay widths for ${\pi }_1(1600)$ and ${\pi }_1(2015)$ do not support their classification as hybrids, implying alternative interpretations, such as tetraquark or molecular configurations. Conversely, the ${\eta }_1(1855)$ is consistent with a mixed hybrid state composed of $(u\bar{u}+d\bar{d})g/\sqrt{2}$ and $s\bar{s}g$ components, with mixing angles ranging from $17.7^{\circ }$ to $84.2^{\circ }$. Additionally, we predict the masses and decay widths of yet-unobserved isoscalar and excited hybrid states, providing valuable targets for future experimental searches. This study not only clarifies the hybrid nature of certain exotic mesons but also contributes to the systematic classification of hybrid states within the meson nonet, thereby enhancing our comprehension of exotic hadronic states.

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

    Reweighting and Analysing Event Generator Systematics by Neural Networks on High-Level Features

    Amon Furuichi🇯🇵 · Sung Hak Lim🇰🇷 · Mihoko M. Nojiri🇯🇵

    The state-of-the-art deep learning (DL) models for jet classification use jet constituent information directly, improving performance tremendously. This draws attention to interpretability, namely, the decision-making process, correlations contributing to the classification, and high-level features (HLFs) representing the difference between signal and background. We address the interpretability issue using a modular architecture called the analysis model (AM), which combines several motivated HLFs as the input. We focus on the generator systematics of the top vs. QCD classification by one of the best classifiers, Particle Transformer (ParT). Taking commonly used event generators Pythia (PY) and Herwig (HW) as examples, we demonstrate that the event weights estimated by the AM generator classifier align the HW classification score distribution to PY ones for QCD jets, with small training uncertainty. This suggests the AM is sufficient to describe simulated QCD jet features with relatively few observables, and generator systematics would also be reduced by reweighting the simulation by data. On the other hand, large event weights are required for QCD-like top jets, which leads to imperfect reweighting for both AM and ParT generator classifiers. Moreover, the AM HLFs are insufficient for describing PY and HW differences, causing lower reweighting accuracy compared with ParT. The missing features are the correlation among the collimated high-energy jet constituents, which are strongly correlated to the energy flow polynomials (EFPs) selected for top vs. QCD classification, showing the complementarity between AM HLFs and the selected EFPs.

    hep-phhep-exJHEP(2025)·1 citation
24. 24*

    Exploring X17 and dark charges in the context of Standard Model tensions

    Antonio Capolupo🇮🇹 · Aniello Quaranta🇮🇹 · Raoul Serao🇮🇹

    We report on recent results, according to which the hyphothetical X17 boson could affect the muon g-2 anomaly and the Lamb Shift. Moreover by considering the kinetic mixing between this new boson and the U(1)Y we establish possible contribution of the X17 to the W mass.

    hep-phhep-thnucl-th1 citation
25. 25*

    Correlated study on some $B_c\to P$ and $B_c\to S$ wave channels in light of new inputs

    Utsab Dey🇮🇳 · Soumitra Nandi🇮🇳

    This study investigates the decay modes of the $B_c$ meson, focusing on semileptonic and nonleptonic decay into S and P wave charmonia. The primary objective is to extract the shape parameter of the $B_c$ meson distribution amplitude through a data-driven approach, utilizing the lattice results on $B_c\to {\eta }_c,J/\psi$ semileptonic form factors and yielding an estimate of ${{\omega }_B}_c=0.998(34)$ for the same. We use the form factors derived from the modified perturbative QCD framework in the analysis. This result and various other inputs on the radiative decays of the P wave charmonia enable us to estimate the $q^2$ shapes of the $B_c\to {\chi }_{c0},{\chi }_{c1}$ and $h_c$ form factors using pole expansion parametrization. Using these results, we have obtained predictions of LFUV observables $R({\chi }_{c0})=0.169(11)$, $R({\chi }_{c1})=0.126(2)$ and $R(h_c)=0.113(3)$. Finally, we have presented predictions for branching ratios of some nonleptonic decay modes of the $B_c$ meson into S and P wave charmonia in the same modified perturbative QCD framework.

    hep-phJHEP(2025)·7 citations
26. 26*

    Gradient corrections to the local-equilibrium energy-momentum tensor in the Zubarev approach

    Sergii V. Akkelin🇺🇦 · Dirk H. Rischke🇩🇪

    We compute the expectation value of the energy-momentum tensor of a real scalar field in an approximation which accounts for spacetime gradients of the hydrodynamical variables in local thermodynamical equilibrium. We show that the energy-momentum tensor receives corrections with respect to the standard local-equilibrium result. Notably, the relation between the energy density and pressure, i.e., the equation of state, is modified with respect to the one in global equilibrium. The obtained corrections might be relevant for systems created in relativistic hadron and heavy-ion collisions.

    hep-phhep-thnucl-thPRD(2025)·2 citations
27. 27*

    Di-decay signature of new physics particles at intensity frontier experiments

    Giovani Dalla Valle Garcia🇩🇪 · Maksym Ovchynnikov🇨🇭

    We present a discovery-era strategy for Intensity Frontier experiments based on ``di-decay'' events, in which feebly interacting particles (FIPs) are produced in pairs and then both decay inside the detector. This signature may exist in broad classes of models with FIPs decaying in the same way as minimal ``portal'' particles. The two displaced vertices may allow reconstruction of the pair invariant mass and hence reveal the production channel, information normally inaccessible at these facilities. This, in turn, lets one discriminate between FIP models that share identical decay signatures. As a case study, we consider the model of Higgs-like scalars and show that SHiP, Belle II, and the Downstream@LHCb can each cover wide domains of viable parameter space using di-decays.

    hep-phPRD(2026)·9 citations
28. 28*

    Inverse bubbles from broken supersymmetry

    Giulio Barni🇪🇸 · Simone Blasi🇩🇪 · Miguel Vanvlasselaer🇧🇪

    Building upon the recent findings regarding inverse phase transitions in the early universe, we present the first natural realisation of this phenomenon within a supersymmetry-breaking sector. We demonstrate that inverse hydrodynamics, which is characterized by the fluid being aspirated by the bubble wall rather than being pushed or dragged, is actually not limited to a phase of (re)heating but can also occur within the standard cooling cosmology. Through a numerical analysis of the phase transition, we establish a simple and generic criterion to determine its hydrodynamics based on the generalised pseudo-trace. Our results provide a proof of principle highlighting the need to account for these new fluid solutions when considering cosmological phase transitions and their phenomenological implications.

    hep-phastro-ph.COhep-thPRD(2025)·8 citations
29. 29*

    Two-loop renormalisation of quark and gluon fields in the SMEFT

    Claude Duhr🇩🇪 · Andres Vasquez🇩🇪 · Giuseppe Ventura🇬🇧 · Eleni Vryonidou🇬🇧

    We compute the contributions of CP-conserving operators in the dimension-six SMEFT to the two-loop renormalisation constants of quark and gluon fields in the $\overline{\text{MS}}$-scheme. Specifically, we consider the top-quark chromomagnetic operator and the triple gluon operator. We work with the background-field method, which allows us to extract the contribution of these operators to the two-loop running of the top mass and the strong coupling constant. We discuss in detail the mixing with the unphysical operators required for the renormalisation, and we present analytic results for the renormalisation constants of all relevant operators.

    hep-phJHEP(2025)·29 citations
30. 30*

    Curvature Perturbations from First-Order Phase Transitions: Implications to Black Holes and Gravitational Waves

    Gabriele Franciolini🇨🇭 · Yann Gouttenoire🇮🇱 · Ryusuke Jinno🇯🇵

    Understanding whether primordial black holes form during strong first-order phase transition (FOPT) is a crucial open question in cosmology. We address this using a fully covariant formalism to study cosmological perturbations, highlighting previously overlooked gauge dependencies. We show that non-covariant treatments can overestimate primordial black holes and scalar-induced gravitational waves. Once gauge dependencies are accounted for, both signals are strongly suppressed, with direct implications for the FOPT interpretation of the Pulsar Timing Array signal.

    hep-phastro-ph.COgr-qcPRL(2026)·48 citations
31. 31*

    LHC Signatures of the Generic Georgi-Machacek Model

    Saiyad Ashanujjaman🇩🇪 · Andreas Crivellin🇨🇭 · Siddharth P. Maharathy🇿🇦 · Anil Thapa🇺🇸

    Vector-boson fusion production of new Higgs bosons decaying into pairs of electroweak gauge bosons ($W^{\pm }{W}^{\pm }$, $WZ$ and $ZZ$) is a smoking-gun signature of the Georgi-Machacek (GM) Model. Notably, ATLAS has observed a $3.3\sigma$ excess in $W^{\pm }{W}^{\pm }$ at $\approx 450$GeV and a $2.8\sigma$ excess in the $WZ$ channel at $\approx 375$GeV, while CMS reported weaker-than-expected limits at these masses. However, the canonical custodial-symmetric GM Model cannot accommodate these signals, as it predicts mass degeneracy among the new gauge-philic Higgs bosons. To overcome this obstacle, we consider a generalized version of the GM Model without the custodial $SU(2{)}_C$ symmetry in the scalar potential. In the limit of small mixing among the Higgs bosons, the $W^{\pm }{W}^{\pm }$ and $WZ$ excesses can be explained by the doubly and singly-charged Higgs bosons originating primarily from the $Y=1$ triplet, while respecting the bounds from $ZZ$ searches. Furthermore, the neutral Higgs boson mostly contained in the $Y=0$ triplet can account for the excess at $\approx 152$GeV in associated di-photon production, while being consistent with constraints from vacuum stability and the Standard Model Higgs signal strength measurements.

    hep-phhep-exPRD(2025)·6 citations
32. 32*

    Can the X(1750) be a $\Phi$(1750)?

    Peter Lichard🇨🇿

    We present the arguments that the X(1750) has the isospin $I=0$, and as such, it belongs to the $\varphi$ family. We base our argumentation on the X(1750) appearing in the $e^{+}{e}^{-}\to K^{+}{K}^{-}$ process as a narrow resonance and not appearing in the $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ process at all.

    hep-phhep-exPRD(2025)·1 citation
33. 33*

    Scotogenic Peccei-Quinn and One-Higgs Quark and Lepton Model with Flavor Symmetry

    Ernest Ma (UC Riverside)🇺🇸

    Implementing the Peccei-Quinn mechanism to enforce CP conservation in strong interactions with heavy dark quarks, a scotogenic model of quark masses with $Z_3\times Z_3$ symmetry is discussed where there is only one Higgs doublet. A natural extension to the lepton sector using $A_4\times A_4$ is also presented.

    hep-phNPB(2025)·1 citation
34. 34*

    Fine-tuning machine-learned particle-flow reconstruction for new detector geometries in future colliders

    Farouk Mokhtar🇺🇸 · Joosep Pata🇪🇪 · Dolores Garcia🇨🇭 · Eric Wulff🇨🇭 · Mengke Zhang🇺🇸 · Michael Kagan🇺🇸 · Javier Duarte🇺🇸

    We demonstrate transfer learning capabilities in a machine-learned algorithm trained for particle-flow reconstruction in high energy particle colliders. This paper presents a cross-detector fine-tuning study, where we initially pretrain the model on a large full simulation dataset from one detector design, and subsequently fine-tune the model on a sample with a different collider and detector design. Specifically, we use the Compact Linear Collider detector (CLICdet) model for the initial training set and demonstrate successful knowledge transfer to the CLIC-like detector (CLD) proposed for the Future Circular Collider in electron-positron mode. We show that with an order of magnitude less samples from the second dataset, we can achieve the same performance as a costly training from scratch, across particle-level and event-level performance metrics, including jet and missing transverse momentum resolution. Furthermore, we find that the fine-tuned model achieves comparable performance to the traditional rule-based particle-flow approach on event-level metrics after training on 100,000 CLD events, whereas a model trained from scratch requires at least 1 million CLD events to achieve similar reconstruction performance. To our knowledge, this represents the first full-simulation cross-detector transfer learning study for particle-flow reconstruction. These findings offer valuable insights towards building large foundation models that can be fine-tuned across different detector designs and geometries, helping to accelerate the development cycle for new detectors and opening the door to rapid detector design and optimization using machine learning.

    ↳ hep-excs.LGhep-phphysics.data-an+1PRD(2025)·16 citations
35. 35*

    Spin precession and neutrino helicity flip under the influence of a gravitational plane wave

    Reza Saadati🇨🇦 · Fayçal Hammad🇨🇦

    We recently studied spin precession in various stationary and axisymmetric spacetimes and applied it to the case of neutrinos propagating in those spacetimes. In this paper, the study of spin precession is extended to the case of a spinning particle propagating within the spacetime of a time-dependent gravitational plane wave. First, the angular velocity of spin precession of a particle propagating in a geodesic along an arbitrary direction relative to the gravitational wave is derived. Our general result is then used to derive the helicity flip probability for neutrinos freely propagating along such an arbitrary direction within the gravitational wave.

    ↳ gr-qchep-phPRD(2025)·0 citations
36. 36*

    2025 update on ${\epsilon }_K$ in the Standard Model with lattice QCD inputs

    Seungyeob Jwa🇰🇷 · Jeehun Kim🇰🇷 · Sunghee Kim🇰🇷 · Sunkyu Lee🇰🇷 · Weonjong Lee · Sungwoo Park🇺🇸

    We present theoretical results for the indirect CP violation parameter, $|{\epsilon }_K|$, evaluated directly within the Standard Model using lattice QCD inputs including $B_K$, $|V_{cb}|$, $|V_{us}|$, $|V_{ud}|$, ${\xi }_0$, ${\xi }_2$, $F_K$, and the charm quark mass $m_c$. Our analysis reveals a significant tension at the $\sim 5\sigma$ level ($4.6\sigma$ to $5.2\sigma$) between the Standard Model prediction and the experimental value of $|{\epsilon }_K|$. The Standard Model prediction, informed by lattice QCD inputs, accounts for only approximately 65% of the experimental value, leaving a 35% discrepancy unexplained. Notably, this tension vanishes when using the inclusive determination of $|V_{cb}|$, derived from heavy quark expansion. The discrepancy is therefore tied to the well-known tension between the exclusive and inclusive determinations of $|V_{cb}|$. We further report results for $|{\epsilon }_K|$ obtained using the Brod--Gorbahn--Stamou (BGS) method based on $u\text{–}t$ unitarity, which yields an even stronger discrepancy, in the range of $4.9\sigma$ to $5.5\sigma$, when combined with lattice QCD inputs.

    ↳ hep-lathep-ph5 citations
37. 37*

    Electron-positron pair production in bound-bound muon transitions

    Oleg Yu. Andreev🇩🇪 · Deyang Yu🇨🇳 · Konstantin N. Lyashchenko🇨🇳 · Daria M. Vasileva🇷🇺

    We explored a distinct mechanism for matter creation via electron-positron pair production during bound-bound transitions in the deexcitation of one-muon ions. For ions with nuclear charges $Z\ge 24$, transitions from low-lying excited states to the 1s-muon state can lead to the production of electron-positron pairs. We show that the Breit interaction determines the transition probabilities for states with nonzero orbital momentum. Although the $2s$ state is metastable, pair production arises mainly from the decay of the $2p$ states. Thus, the Breit interaction governs electron-positron pair production in bound-bound muon transitions. This process offers a unique opportunity to explore quantum electrodynamics in strong fields, as well as a class of nonradiative transitions involving electron-positron pair production.

    ↳ physics.atom-phhep-ph1 citation
38. 38*

    Cosmic Strings-induced CMB anisotropies in light of Weighted Morphology

    Adeela Afzal🇵🇰 · M. Alakhras🇮🇷 · M. H. Jalali Kanafi🇮🇷 · S. M. S. Movahed🇮🇷

    Motivated by the morphological measures in assessing the geometrical and topological properties of a generic cosmological stochastic field, we propose an extension of the weighted morphological measures, specifically the $n$th conditional moments of derivative (cmd-$n$). This criterion assigns a distinct weight to each excursion set point based on the associated field. We apply the cmd-$n$ on the Cosmic Microwave Background (CMB) to identify the cosmic string networks (CSs) through their unique Gott-Kaiser-Stebbins effect on the temperature anisotropies. We also formulate the perturbative expansion of cmd-$n$ for the weak non-Gaussian regime up to $\mathcal{O}({\sigma }_0^3)$. We propose a comprehensive pipeline designed to analyze the morphological properties of string-induced CMB maps within the flat sky approximation. To evaluate the robustness of our proposed criteria, we employ string-induced high-resolution flat-sky CMB simulated patches of $7.2$ deg${}^2$ size with a resolution of $0.42$ arc-minutes. Our results demonstrate that the minimum detectable value of cosmic string tension is $G\mu \gtrsim 1.9\times 10^{-7}$ when a noise-free map is analyzed with normalized cmd-$n$. Whereas for the ACT, CMB-S4, and Planck-like experiments at 95.45\% confidence level, the normalized cmd-$n$ can distinguish the CSs network for $G\mu \gtrsim 2.9\times 10^{-7}$, $G\mu \gtrsim 2.4\times 10^{-7}$ and $G\mu \gtrsim 5.8\times 10^{-7}$, respectively. The normalized cmd-$n$ exhibits a significantly enhanced capability in detecting CSs relative to the Minkowski Functionals.

    ↳ astro-ph.COastro-ph.IMhep-phphysics.comp-ph+1MNRAS(2025)·4 citations
39. 39*

    Thermodynamics of strongly magnetized dense quark matter from hard dense loop perturbation theory

    Sarthak Satapathy🇮🇳 · Sumit🇨🇳 · Salman Ahamad Khan🇮🇳

    We discuss the hard dense loop perturbation theory approach for studying the thermodynamics of strongly magnetized dense quark matter. The free energy of quarks and gluons have been calculated for one-loop quark and gluon self-energies, respectively. The longitudinal and transverse components of pressure, magnetization, second-order quark number susceptibility, and speed of sound have been computed, and their behavior with chemical potential and magnetic field has been analyzed. Our numerical results show that the longitudinal pressure increases with chemical potential and magnetic field, while for the transverse component, it is diminished. We also analyze the longitudinal component of the speed of sound at high chemical potentials, which approaches the speed of light in the asymptotic limit. The obtained results may be helpful in studying magnetized quark matter in the core of neutron stars and magnetars.

    ↳ nucl-thhep-phhep-thPRD(2025)·3 citations
40. 40*

    Gravitational waves from vacuum bubbles: Ultraviolet dependence on wall thickness

    Jun-Chen Wang🇨🇳 · Shao-Jiang Wang🇨🇳 · Zi-Yan Yuwen🇨🇳

    The gravitational wave (GW) spectrum from the first-order phase transition can be characterized by a few phenomenological parameters but with high degeneracies in model/data distinguishments. In this paper, we look into the high-frequency power law of the GW spectrum with preliminary numerical simulations for both quantum and semiclassical pictures of vacuum decay. We first reveal an anticorrelation of the high-frequency power law to a certain power of the ratio between the wall thickness and bubble radius at the onset of bubble collisions, which can be further approximated analytically by some other phenomenological model characteristics to break the model degeneracy.

    ↳ gr-qcastro-ph.COhep-phPRD(2025)·7 citations
41. 41*

    Running vacuum and H^4-inflation

    Joan Solà Peracaula🇪🇸 · Cristian Moreno-Pulido🇪🇸 · Alex González-Fuentes🇪🇸

    Recent studies of QFT in cosmological spacetime indicate that the speeding up of the present universe may not just be associated with a rigid cosmological term but with a running one that evolves with the expansion rate: $\Lambda =\Lambda (H)$. This running is inherited from the cosmic evolution of the vacuum energy density (VED), ${\rho }_{\mathrm{vac}}$, which is sensitive to quantum effects in curved spacetime that ultimately trigger that running. The VED is a function of the Hubble rate and its time derivatives: ${\rho }_{\mathrm{vac}}={\rho }_{\mathrm{vac}}(H,\dot{H},\ddot{H},...)$. Two nearby points of the cosmic evolution during the FLRW epoch are smoothly related as $\delta {\rho }_{\mathrm{vac}}\sim \mathcal{O}(H^2)$. In the very early universe, in contrast, the higher powers of the Hubble rate take over and bring about a period of fast inflation. They originate from quantum effects on the effective action of vacuum, which we compute. Herein we focus on the lowest possible power for inflation to occur: $H^4$. During the inflationary phase, $H$ remains approximately constant and very large. Subsequently, the universe enters the usual FLRW radiation epoch. This new mechanism (`RVM-inflation') is not based on any supplementary `inflaton' field, it is fueled by pure QFT effects on the dynamical background and is different from Starobinsky's inflation, in which $H$ is never constant.

    ↳ gr-qcastro-ph.COhep-phhep-thUniverse(2025)·11 citations
42. 42*

    Asymmetrical cavity design that bypasses mode mixings in axion haloscope experiments

    Byeong Rok Ko🇰🇷 · Andrew K. Yi🇺🇸

    Microwave cavities used in axion haloscope experiments typically employ a tuning rod as a means to widen the range of resonance frequencies at which it is sensitive to axion-to-photon conversion. A realistic tuning mechanism requires a gap between the cavity end caps and the tuning rod to ensure movement, and causes some modes to hybridize with the resonant mode that is being tracked for the experiment. These so-called mode mixings lead to gaps in the frequency range that practically lose sensitivity to axions. In order to solve this problem, we present a cavity design which, for two tuning rod configurations corresponding to a lower and higher frequency range, have a dielectric rod inserted at a specific location that makes the cavity asymmetrical. Moving the tuning rod closer to the dielectric insert changes the location and frequency of the mode mixing compared to when it is farther away from it. This design is easily realizable in practical experiments and makes possible an axion dark matter search with minimal loss in sensitivity due to mode mixings. We also show that the same design has the same desired effect when cavity dimensions are scaled down to be smaller and are at higher resonance frequencies.

    ↳ hep-exhep-phphysics.ins-detJ.Korean Phys.Soc.(2025)·0 citations
43. 43*

    An 85-s X-ray quasi-periodicity after a stellar tidal disruption by a candidate intermediate-mass black hole

    Wenjie Zhang · Xinwen Shu🇨🇳 · Luming Sun🇨🇳 · Rongfeng Shen · Liming Dou · Ning Jiang · Tinggui Wang

    It is still in dispute the existence of intermediate-mass black holes (IMBHs) with a mass of ~10^3-10^5 solar masses (Msun), which are the missing link between stellar-mass black holes (5-50 Msun) and supermassive black holes (10^6-10^10 Msun). The bright flares from tidal disruption events (TDEs) provide a new and direct way to probe IMBHs. 3XMM J215022.4-055108 is a unique off-nuclear X-ray transient which can be best explained as the TDE by an IMBH in a massive star cluster, though its mass is not well determined. Here, we report the discovery of a transient X-ray quasi-periodicity signal from 3XMM J215022.4-055108 with a period of ~85 seconds (at a significance of >3.51sigma) and fractional root-mean-squared amplitude of ~10%. Furthermore, the signal is coherent with a quality factor ~16. The significance drops to >3.13sigma if considering all light curves with sufficient quality for QPO search. Combining with the results from X-ray continuum fittings, the detection of QPO allows for joint constraints on the black hole mass and dimensionless spin in the range [9.9*10^3-1.6*10^4 Msun]$ and [0.26-0.36], respectively. This result supports the presence of an IMBH in an off-nuclear massive star cluster and may open up the possibility of studying IMBHs through X-ray timing of TDEs.

    ↳ astro-ph.HEhep-phNature Astron.(2025)·10 citations
44. 44*

    ASKAP observations of the radio shell in the composite supernova remnant G310.6-1.6

    Wenhui Jing (YNU) · Jennifer L. West (DRAO) · Xiaohui Sun (YNU) · Wasim Raja (CSIRO) · Xianghua Li (YNU)🇨🇳 · Lingxiao Dang (NJU)🇨🇳 · Ping Zhou (NJU)🇨🇳 · Miroslav D. Filipovic (WSU)🇦🇺 · Andrew M. Hopkins (MQU) · Roland Kothes (DRAO) · Sanja Lazarevic (WSU)🇦🇺 · Denis Leahy (University of Calgary)🇬🇧 and 3 other authors

    We report the observations of the radio shell of the supernova remnant (SNR) G310.6-1.6 at 943 MHz from the Evolutionary Map of the Universe (EMU) and the Polarization Sky Survey of the Universe's Magnetism (POSSUM) surveys by using the Australian Square Kilometre Array Pathfinder (ASKAP). We detect polarized emission from the central pulsar wind nebula (PWN) with rotation measures varying from -696 rad m${}^{-2}$ to -601 rad m${}^{-2}$. We measure the integrated flux density of the shell to be 36.4 +/- 2.2 mJy at 943 MHz and derive a spectral index of -0.4 +/- 0.1 for the PWN and -0.7 +/- 0.3 for the SNR shell. From the combined radio and X-ray observations, the object can be identified as a supernova explosion of about 2500 yr ago with energy of about 1.3 x 10${}^{50}$ erg, suggesting an ejected mass of about 10 M_sun. The circular radio shell outside the circular hard X-ray shell is unique among Galactic SNRs. We discuss several possible scenarios, including blast wave, reverse shock, and pulsar-fed emission, but find that none of them can fully explain the observed characteristics of the shell. This poses a challenge for understanding the evolution of SNRs. The results of this paper demonstrate the potential of the ASKAP EMU and POSSUM surveys in discovering more objects of small angular size and low surface brightness.

    ↳ astro-ph.GAastro-ph.HEhep-ph0 citations
45. 45*

    Neutrinos from dense environments

    M. Cristina Volpe (CNRS, APC)🇫🇷

    Neutrinos from dense environments are unique laboratories for astrophysics, particle physics and many-body physics. They tell us about the last stages of the gravitational core-collapse and the explosion of massive stars. These elusive particles are also tightly linked to heavy elements synthesis in gravitational core-collapse supernovae and binary neutron star mergers, or play a pivotal role at the MeV epoch during the Universe expansion. We highlight theoretical and observational aspects of this interesting domain, in particular for the future measurement of neutrinos from the next core-collapse supernova, and of the diffuse supernova background, whose discovery might lie in the forthcoming future.

    ↳ astro-ph.HEastro-ph.SRhep-phnucl-th0 citations
46. 46*

    Magnetar structure in non-linear electrodynamics with mixed poloidal-toroidal fields

    Arthur G. Suvorov🇪🇸 · José A. Pons🇪🇸

    Magnetars have inferred polar field strengths in excess of the Schwinger limit, where non-linear electromagnetic effects can be significant. Their internal fields may be even stronger, suggesting that Maxwellian characterizations of hydromagnetic structure may require revision. A generalized Grad-Shafranov equation, describing static and axisymmetric fluid stars with mixed poloidal-toroidal fields, is introduced and subsequently solved in a perturbative scheme to calculate quadrupolar deformations. In the Born-Infeld theory, we show that the toroidal field has a maximum strength set by the scale parameter, $b$, implying an upper limit to the stellar prolateness, $|{ϵ}_{\max }|\sim 10^{-5}{\left(b/10^{16}\text{ G}\right)}^2$, that is independent of field specifics. Observations of magnetar phenomena that are interpreted as evidence for ellipticity, such as precession, can thus implicitly constrain post-Maxwellian parameters in a way that complements terrestrial experiments. Toroidal ceilings also have implications for dynamo theory and gravitational waves, which we revisit together with field evolution in crusts abiding by beyond-Maxwell physics.

    ↳ astro-ph.HEgr-qchep-phhep-thMNRAS(2025)·7 citations
47. 47*

    Charmed hadron production from secondary anti-proton + proton annihilations in p+A reactions at FAIR

    Tom Reichert🇩🇪 · Jan Steinheimer🇩🇪 · Marcus Bleicher🇩🇪

    We present estimates for the production cross sections of exotic states (${\Lambda }_c,{\Sigma }_c,{\Xi }_c,D\mathrm{and}{D}_s$) from secondary $\overline{B}+B$ annihilations in p+A reactions from $E_{\mathrm{lab}}=10-30A$~GeV. We focus specifically on the newly planned hadron physics program of CBM at FAIR. These estimates for the production of exotic states are based on the achievable number of $\overline{B}+B$ annihilations and their invariant mass distributions calculated in the UrQMD transport model.

    ↳ nucl-thhep-phnucl-exEPJA(2025)·5 citations
48. 48*

    Kelvin waves in nonequilibrium universal dynamics of relativistic scalar field theories

    Viktoria Noel🇩🇪 · Thomas Gasenzer🇩🇪 · Kirill Boguslavski🇦🇹

    We investigate the different degrees of freedom underlying far-from-equilibrium scaling behaviour in a relativistic, single-component $\mathrm{O}(1)$ scalar field theory in two and three spatial dimensions. In such a strongly correlated many-body system, identifying the respective roles of nonlinear wave excitations and defect dynamics is a prerequisite for understanding the universal character of time evolution far from equilibrium and thus the different possible universality classes of nonthermal fixed points. Using unequal-time two-point correlation functions, we extract information about the dominant infrared excitations and study their connections to the turbulent dynamics of topological defects created in the system. In three dimensions, the primary excitations are identified as kelvon quasiparticles, which are quantised Kelvin waves propagating along vortex lines, while in two dimensions, vortices are point defects, and the infrared dynamics is dominated by bound-state like excitations similar to Kelvin waves. In both cases, the kelvon excitations are found to be characterised by distinct time-evolving dispersion relations, subject to the coarsening dynamics close to the respective nonthermal fixed point and, thus, to the decay of superfluid turbulence in the system. Our results underline the role of topological defects and their influence on the universal dynamics of strongly correlated systems near nonthermal fixed points, complementing the analysis of large-$N$ models in $\mathrm{O}(N)$ systems.

    ↳ cond-mat.quant-gascond-mat.stat-mechhep-phPRResearch(2025)·8 citations
49. 49*

    Gravitational wave cosmology in Einstein-scalar-Gauss-Bonnet gravity

    Jared Fier🇺🇸 · Henry Han🇺🇸 · Bowen Li🇺🇸 · Kai Lin🇧🇷 · Shinji Mukohyama🇯🇵 · Anzhong Wang🇺🇸

    In the framework of Einstein-scalar-Gauss-Bonnet (EsGB) gravity, we systematically study gravitational waves (GWs), first produced by remote compact astrophysical sources and then propagating through the flat homogeneous and isotropic Universe at cosmic distances before arriving at detectors. Assuming that the speed $c_T$ of the spin-2 graviton is the same as that of photons, we find explicitly the stability conditions of the theory and then obtain the severest observational constraint found so far. In particular, all these conditions and constraints are satisfied, provided that $0\le \alpha \dot{f}({\varphi }_0)\lesssim 8.97\times 10^{-24}$ (km), where $\alpha f(\varphi )$ denotes the coupling strength between the scalar field $\varphi$ and the Gauss-Bonnet term, an over-dot represents the derivative with respect to the cosmic time, and ${\varphi }_0$ is the present value of $\varphi$. The trajectories for both spin-2 and spin-0 gravitons and the amplitudes of GWs along the trajectories are explicitly obtained. The amplitude of a spin-2 GW is practically indistinguishable from that of GR, while the spin-0 GWs remain almost constant during radiation- and matter-dominated epochs, and in the dark energy-dominated epoch it is proportional to the physical distance between the source and the observer. A careful analysis shows that the latter is due to the assumption $c_T=1$. When $c_T\ne 1$ to the extent that is consistent with the stability conditions and observational constraints, the above behavior disappears.

    ↳ gr-qcastro-ph.COhep-phhep-th10 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.