Wed·Sep 18, 2024Wednesday·September 18, 2024

1. 01*

   Probing neutrino millicharges at the European Spallation Source

   Alexander Parada🇨🇴 · G. Sanchez Garcia🇪🇸

   We study the potential of a set of future detectors, proposed to be located at the European Spallation Source (ESS), to probe neutrino millicharges through coherent elastic neutrino-nucleus scattering. In particular, we focus on detectors with similar characteristics as those that are under development for operation at the ESS, including detection technologies based on cesium iodine, germanium, and noble gases. Under the considered conditions, we show that the Ge detector, with a lighter nuclear target mass with respect to CsI and to a noble gas like Xe, is more efficient to constrain neutrino millicharges, reaching a sensitivity of $\sim 10^{-9}e$ for diagonal neutrino millicharges, and $\sim 10^{-8}e$ for the transition ones. In addition, we study the effects of including electron scattering processes for the CsI detector, achieving an expected sensitivity of $\sim 10^{-10}e$ for the diagonal millicharges.

   hep-phPRD(2025)·2 citations
2. 02*

   Theoretical Probes of Higgs-Axion non-perturbative Couplings

   V.K. Oikonomou🇬🇷

   In this work we investigate the phenomenological implications of several non-trivial axion-Higgs couplings, which cover most of the possible non-perturbative scenarios. Specifically we consider the combination of having higher order non-renormalizable Higgs-axion couplings originating from a weakly coupled effective theory combined with non-perturbative couplings of the form $\sim ϵ{\Lambda }_c^2|H{|}^2\cos (\frac{\varphi }{f_a})$. Since we consider the misalignment axion, the non-perturbative couplings can be expanded in the form of a perturbation expansion in powers of $\varphi /f_a$, thus after the electroweak symmetry breaking, the effective potential of the axion is drastically affected by these terms. We investigate the phenomenological implications of these terms for various values of the mass scale ${\Lambda }_c$, and some scenarios are theoretically disfavored, while other scenarios with non-perturbative Higgs-axion couplings of the form $\sim ϵ{\Lambda }_c^2|H{|}^2\cos (\frac{\varphi }{f_a})$ with ${\Lambda }_c\sim 10^{-10}\times m_a$ and $m_a\sim 10^{-10}$eV, lead to a characteristic pattern in the stochastic gravitational wave background via the deformation of the background equation of state parameter occurring at frequencies probed by the Einstein Telescope. We also consider loop effects from the Higgs sector caused by the term $\sim ϵ{\Lambda }_c^2|H{|}^2\cos (\frac{\varphi }{f_a})$ if we close the Higgs in one loop.

   hep-phastro-ph.COgr-qchep-thPRD(2024)·2 citations
3. 03*

   The higher ${\chi }_{cJ}(nP)$, $h_c(nP)$ states and the role of the gluon-exchange potential

   A. M. Badalian🇷🇺

   The masses, the fine-structure splitting, and two-photon decay widths of the higher $nP$-charmonium states are calculated in the relativistic string model, reduced to the spinless Salpeter equation, where the static potential has no fitting parameters and the $c-$quark mass has the physical value. The resulting masses of $h_c(3P)$, ${\chi }_{c1}(3P)$, ${\chi }_{c0}(4P)$, ${\chi }_{c0}(5P)$, ${\chi }_{c1}(5P)$ are obtained in a good agreement with the experimental masses of the LHCb resonances: $h_c(4300)$, ${\chi }_{c1}(4274)$, $X(4500)$, $X(4700)$, $X(4685)$. To test sensitivity of results to a chosen gluon-exchange (GE) potential, three types of $V_{ge}(r)$ are considered. In first case the non-screened GE potential with large vector coupling at asymptotic, ${\alpha }_{\mathrm{V}}(asym.)=0.635$, and the $c$-quark mass $m_c=1.430$ GeV are taken; in second case a screened $V_{ge}$ and $m_c=1.385$ are investigated, and in third case the GE potential is totally suppressed, $V_{ge}=0$, and $m_c=1.32$ GeV. The agreement with experiment is reached only if the same (universal) flattened confining potential, introduced in the analysis of the radial Regge trajectories of light mesons, is used. The unobserved $6P,0^{+}$ resonance with the mass $\cong 4.81$ GeV, near $J/\psi \varphi (1680)$ threshold, is predicted. Our analysis shows that the screening of the GE potential is possible but weakly affects the physical results obtained. The calculated two-photon decay widths weakly differ in the three cases but may become an important factor, which distinguishes $c\bar{c}$ and four-quark states.

   hep-phhep-exhep-latPhys.Atom.Nucl.(2024)·1 citation
4. 04*

   A Three-Coupled-Channel Analysis of $Z_c(3900)$ Involving $D{\bar{D}}^{\ast }$, $\pi J/\psi$, and $\rho {\eta }_c$

   Kang Yu🇨🇳 · Guang-Juan Wang🇯🇵 · Jia-Jun Wu🇨🇳 · Zhi Yang🇨🇳

   In this work, we conduct a three-coupled-channel analysis of the $Z_c(3900)$ structure, focusing on the $D{\bar{D}}^{\ast }$, $J/\psi \pi$, and $\rho {\eta }_c$ channels, based on the one-boson exchange model. Drawing from previous study on the exotic state $T_{cc}$, we only utilize one more parameter to construct the interactions between the channels. Our model successfully reproduces the experimental line shapes of the invariant mass distribution at $\sqrt{s}=4.23$ and $4.26$ GeV for the three channels. Additionally, the finite-volume energy levels in our model show agreement with current LQCD conclusion. Detailed analysis suggests that the $Z_c(3900)$ peaks in the $\pi J/\psi$ and $\rho {\eta }_c$ distributions primarily arise from the triangle loop involving the $D_1\bar{D}{D}^{\ast }$ intermediate system. In the $D{\bar{D}}^{\ast }$ distribution, the threshold peak is generated by the cascade decay mechanism enhanced by a triangle diagram. Moreover, we find a virtual pole located far from the threshold, indicating that $Z_c(3900)$ peaks are not associated with physical pole. We conclude that the $Z_c(3900)$ peaks are predominantly caused by the threshold cusp.

   hep-phPRD(2024)·16 citations
5. 05*

   Lepton seesaw model in a modular $A_4$ symmetry

   Takaaki Nomura🇨🇳 · Hiroshi Okada🇨🇳

   We propose a lepton seesaw model to get the same mass-origin of charged-leptons and neutrinos introducing a modular $A_4$ symmetry. In this scenario, the mass matrix of charged-leptons is induced via seesaw-like mechanism while the mass matrix of neutrino is realized via an inverse seesaw mechanism with help of vector-like fermions and an isospin singlet and triplet scalar field with nonzero vacuum expectation values. In analyzing the model we concentrate on fixed points of modulus $\tau$ that is favored by a flux compactification of Type IIB string theory. We search for allowed region at nearby these fixed points and find good solutions at nearby $\tau =\omega$ with several good predictions.

   hep-phJ.Subatomic Part.Cosmol.(2026)·14 citations
6. 06*

   Thermodynamic properties of gluon plasma: A q-potential approach

   Guruprasad Kadam🇮🇳

   In this work, we study the thermodynamic properties of quark-gluon plasma using Kramer's $q-potential$ method. We propose a modification in the first law of thermodynamics by including a temperature-dependent term when single particle energies themselves are temperature-dependent. With this modified first law, we derive an expression for pressure starting from Kramer's $q-potential$. We find that to maintain thermodynamic consistency, pressure receives an additional term solely due to medium-dependent dispersion relation. The energy density, by definition, remains a sum over all the single-particle energies with an appropriate weight factor. We confront this quasiparticle model with the lattice QCD data of SU(3) pure gluon plasma.

   hep-phnucl-th0 citations
7. 07*

   Zero-jettiness soft function to third order in perturbative QCD

   Daniel Baranowski🇨🇭 · Maximilian Delto🇩🇪 · Kirill Melnikov🇩🇪 · Andrey Pikelner🇩🇪 · Chen-Yu Wang🇩🇪

   We present the high-precision result for the zero-jettiness soft function at next-to-next-to-next-to-leading order (N3LO) in perturbative QCD. At this perturbative order, the soft function is the last missing ingredient required for the computation of a hadronic colour singlet production or a colour singlet decay into two jets using the zero-jettiness variable as the slicing parameter. Furthermore, the knowledge of the N3LO soft function enables the re-summed description of the thrust distribution in the process $e^{+}{e}^{-}\to \text{hadrons}$ through next-to-next-to-next-to-leading logarithmic order, which is important for the extraction of the strong coupling constant using this shape variable. On the methodological side, the complexity of the zero-jettiness variable forced us to develop a new semi-analytic method for phase-space integration in the presence of constraints parameterized through Heaviside functions which, hopefully, will be useful for further development of the $N$-jettiness slicing scheme.

   hep-phhep-thPRL(2025)·21 citations
8. 08*

   Spin kinetic theory with a nonlocal relaxation time approximation

   Nora Weickgenannt🇫🇷 · Jean-Paul Blaizot🇫🇷

   We present a novel relaxation time approximation for kinetic theory with spin which takes into account the nonlocality of particle collisions. In particular, it models the property of the microscopic nonlocal collision term to vanish in global, but not in local equilibrium. We study the asymptotic distribution function obtained as the solution of the Boltzmann equation within the nonlocal relaxation time approximation in the limit of small gradients and short relaxation time. We show that the resulting polarization agrees with the one obtained from the Zubarev formalism for a certain value of a coefficient that determines the time scale on which orbital angular momentum is converted into spin. This coefficient can be identified with a parameter related to the pseudo gauge choice in the Zubarev formalism. Finally, we demonstrate how the nonlocal collision term generates polarization from vorticity by studying a nonrelativistic rotating cylinder both from kinetic and hydrodynamic approaches, which are shown to be equivalent in this example.

   hep-phnucl-thPRD(2025)·17 citations
9. 09*

   Dark photon production via inelastic proton bremsstrahlung with Pauli form factor

   Dmitry Gorbunov🇷🇺 · Ekaterina Kriukova🇷🇺

   We study the production of vector portal mediators, dark photons, with masses in the range 0.4--1.8\,GeV in proton-proton collisions via the process of inelastic proton bremsstrahlung. In contrast to previous studies, we take into account the contribution of Pauli electromagnetic form factor to differential cross section and introduce two new splitting functions of the proton. We show that their contributions can become leading in the mass region 0.9--1.8\,GeV and present the updated estimate for the sensitivity of the future SHiP experiment to visible decays of dark photons.

   hep-phPhys.Part.Nucl.(2025)·8 citations
10. 10*

    Searches for long-lived dark photons at proton accelerator experiments

    Yehor Kyselov🇺🇦 · Maksym Ovchynnikov🇨🇭

    A systematic and unified analysis of the capability of lifetime frontier experiments to probe the parameter space of hypothetical long-lived particles is crucial for defining the targets of future searches. However, such a comprehensive study has not yet been conducted for dark photons - hypothetical massive particles that kinetically mix with Standard Model photons. Existing studies often rely on outdated assumptions about dark photon phenomenology, leading to inaccurate calculations of the parameter space, including regions already excluded or relevant for future experiments. In this paper, we present a comprehensive calculation of the parameter space for GeV-scale dark photons and light dark matter accessible to lifetime frontier experiments. Our analysis highlights how theoretical uncertainties in dark photon phenomenology can significantly impact experimental sensitivity across coupling and mass parameters. To facilitate further investigation, we provide these results in a publicly accessible form, incorporating updated dark photon phenomenology into the event generator \texttt{SensCalc}.

    hep-phPRD(2025)·23 citations
11. 11*

    Identifying Neutrino Mass Ordering with Cosmic Gravitational Focusing

    Shao-Feng Ge🇨🇳 · Liang Tan🇨🇳

    The cosmic gravitational focusing (CGF) of relic neutrinos can provide an independent measurement of the absolute neutrino masses $m_i$ with fourth-power dependence ($m_i^4$). We demonstrate in this paper for the first time how this can help identifying the neutrino mass ordering, using the fact that total mass falling below the inverted ordering threshold allows the discrimination of the inverted ordering. Upon incorporating the projected CGF sensitivity at DESI, the preference for the normal ordering with a prior $\sum m_i>0.059\mathrm{eV}$ would increase from the original 89.9\% of the existing matter clustering method with the DESI analysis to 98.2\% while the inverted ordering is further disfavored from 10.1\% to 1.8\%. We also show how this can affect the prospects of the neutrinoless double beta decay and single beta decay measurements.

    hep-phastro-ph.COPRD(2025)·10 citations
12. 12*

    Approximation method for the nuclear structure functions at small $x$

    G.R.Boroun🇮🇷

    We have shown that the relationship between the DIS structure functions is stable for a nuclear target with mass number A at $x\le 10^{-3}$. Numerical results are provided for the specific nuclei 12C and 208Pb using the nuclear PDF parameterizations implemented in the HIJING2.0 model. These results fall whithin the EIC kinematic acceptance for heavy ion running. The ratio $R_{F_L}^A$ is calculated as the ratio $R_{F_2}^A$ in the HIJING2.0 model.

    hep-phnucl-thPramana(2025)·1 citation
13. 13*

    Constraints on the maximal number of dark degrees of freedom from black hole evaporation, cosmic rays, colliders, and supernovae

    Christopher Ewasiuk🇺🇸 · Stefano Profumo🇺🇸

    A dark sector with a very large number of massive degrees of freedom is generically constrained by radiative corrections to Newton's constant. However, there are caveats to this statement, especially if the degrees of freedom are light or mass-less. Here, we examine in detail and update a number of constraints on the possible number of dark degrees of freedom, including from black hole evaporation, from perturbations to systems including an evaporating black hole, from direct gravitational production at colliders, from high-energy cosmic rays, and from supernovae energy losses.

    hep-phastro-ph.COastro-ph.HEhep-thPRD(2025)·9 citations
14. 14*

    Hidden strangeness in meson weak decays to baryon pair

    Chao-Qiang Geng🇨🇳 · Xiang-Nan Jin🇨🇳 · Chia-Wei Liu🇨🇳 · Xiao Yu🇨🇳

    Our study focuses on the weak decay of $D_s^{+}\to p\overline{n}$, which is the only possible two-body baryonic decay in the $D$ meson system. An analysis using perturbative quantum chromodynamics (pQCD) is challenging in this decay due to the small amount of energy released. In particular, naive factorization, suppressed by the light quark masses, results in a minor contribution to this channel. In the framework of final state interactions, the hidden strangeness in the intermediate state naturally avoids this chiral suppression from light quark masses. The branching fraction is predicted to be $\mathcal{B}(D_s^{+}\to p\overline{n})=(1.43\pm 0.10)\times 10^{-3}$, in agreement with the experimental value of $(1.22\pm 0.11)\times 10^{-3}$. We also analyze the decays of $B$ mesons into two charmed baryons involving annihilation-type topological diagrams. In these decays, we conduct a joint analysis of naive factorization and final state interactions. Using the experimental upper bound of $\mathcal{B}(B_s^0\to {\Lambda }_c^{+}{\overline{\Lambda }}_c^{-})<8\times 10^{-5}$, we set a constraint on the coupling constant $g_{D^{+}{\Lambda }_c^{+}n}<7.5$. Final state interactions lead to a prediction of the decay parameter $\gamma (B_s^0\to {\Lambda }_c^{+}{\overline{\Lambda }}_c^{-})>0.8$, whereas pQCD predicts it to be negative. We propose future measurements of $B^0\to {\Xi }_c^{+}{\overline{\Xi }}_c^{-}$, predicting a significant $SU(3{)}_F$ breaking effect with $\frac{\mathcal{B}(B^0\to {\Xi }_c^{+}{\overline{\Xi }}_c^{-})}{\mathcal{B}(B_s^0\to {\Lambda }_c^{+}{\overline{\Lambda }}_c^{-})}=1.4\%$, contrary to the naive estimate of $5.3\%$. We strongly recommend future measurements.

    hep-phhep-exPRD(2024)·6 citations
15. 15*

    Pauli form factor contributions to the inelastic proton bremsstrahlung and dark photon production

    Dmitry Gorbunov🇷🇺 · Ekaterina Kriukova🇷🇺

    We study the production of hypothetical vector particles, dark photons ${\gamma }^{\prime }$, with masses in the range 0.4--1.8 GeV via inelastic proton bremsstrahlung. We further develop the approach of arXiv:2409.11089 and refs. [2-3], where for the first time we considered the contributions to the cross section that are associated with the Pauli form factor in $pp{\gamma }^{\prime }$ vertex and obtained new splitting functions. We demonstrate numerically the importance of these corrections to full inelastic proton bremsstrahlung cross section and refine the sensitivity of the ongoing and future fixed-target experiments T2K, DUNE and SHiP to the parameters of dark photon model. A dedicated experiment on measurements of the proton electromagnetic form factors in the time-like region below the proton-antiproton threshold, like those suggested in PANDA at FAIR, would help to obtain the robust predictions for the dark photon production by a proton beam at fixed target.

    hep-phJHEP(2025)·12 citations
16. 16*

    The $e^{+}{e}^{-}\to ZH$ Process in the SMEFT Beyond Leading Order

    Konstantin Asteriadis🇩🇪 · Sally Dawson🇺🇸 · Pier Paolo Giardino🇪🇸 · Robert Szafron🇺🇸

    We systematically study potential effects of Beyond the Standard Model physics in the $e^{+}{e}^{-}\to ZH$ process. To this end, we include all relevant dimension-6 Standard Model Effective Field Theory operators and work to next-to-leading order (NLO) accuracy in the electroweak coupling. We consider both polarized and unpolarized electron and positron beams and present results for $\sqrt{s}=240,365$ and $500\mathrm{GeV}$, emphasizing contributions where the NLO predictions differ significantly from the leading order results. At NLO, a sensitivity arises to operators that do not contribute at tree level, such as the Higgs tri-linear coupling, CP-violating operators, and dimension-6 operators involving the top quark, among many others. We compare the prospects of future $e^{+}{e}^{-}$ colliders to explore these new physics effects with existing measurements from the LHC, electron EDMs (for CP violating operators), and Z pole measurements.

    hep-phJHEP(2025)·35 citations
17. 17*

    SpectrAx: Spectral Search of Axion-Like Particles Using Multi-Band Observations of Galaxy Clusters from SKA, SO, CMB-S4 and eROSITA

    Harsh Mehta🇮🇳 · Suvodip Mukherjee🇮🇳

    The existence of axions or Axion-Like Particles (ALPs) has been predicted by various Beyond Standard Model (BSM) theories, and the proposed photon-ALP interaction is one of the ways to probe them. Such an interaction will lead to photon-ALP resonant conversion in galaxy clusters, resulting in a polarized spectral distortion in the CMB along the cluster line of sight. The estimation of this signal from galaxy clusters requires an estimation of their electron density and magnetic field profiles, as well as their redshifts. We have developed a new Bayesian framework \texttt{SpectrAx} that can use observations from different electromagnetic bands such as radio, CMB, optical, and X-ray to infer the astrophysical properties of a galaxy cluster, such as cluster its redshift, electron density and magnetic field, along with the BSM physics such as ALPs. We use simulated redshifts in our analysis, but that can be obtained by cross-matching with optical surveys having overlapping sky regions with the galaxy clusters. Also, we use radial profiles that are motivated from observations of galaxy clusters at low redshifts. By using the simulated data corresponding to the ALP mass of $10^{-14}$ eV for upcoming CMB surveys such as Simons Observatory (SO) and CMB-S4 in combination with Square Kilometer Array (SKA) and extended ROentgen Survey with an Imaging Telescope Array (eROSITA) we demonstrate the capability in accurately inferring the ALPs coupling strength along with the radial profile of electron density and magnetic field from galaxy clusters. The application of this framework to the data from future surveys by combining SKA+SO+eROSITA and SKA+CMB-S4+eROSITA will make it possible for the first time to explore both astrophysics and BSM physics from low-redshift galaxy clusters using a multi-band approach.

    ↳ astro-ph.COastro-ph.HEhep-phJCAP(2025)·5 citations
18. 18*

    Antistatic-antistatic $\bar{Q}\bar{Q}qq$ potentials for $u$, $d$ and $s$ light quarks from lattice QCD

    Pedro Bicudo🇵🇹 · Marina Krstic Marinkovic🇨🇭 · Lasse Müller🇩🇪 · Marc Wagner🇩🇪

    We report on our ongoing lattice QCD computation of antistatic-antistatic potentials in the presence of two light quarks using the CLS $N_f=2$ gauge configurations and the OpenQ*D codebase. We utilize a set of 16 creation operators, corresponding to 8 sectors characterized by angular momentum and parity quantum numbers for light quarks $qq=(ud-du)/\sqrt{2}$ (isospin $0$), $qq\in \{uu,(ud+du)/\sqrt{2},dd\}$ (isospin $1$) and $qq\in \{us,ds\}$ (isospin $1/2$ and strangeness $-1$). We improve on previous work by considering a large number of off-axis separations of the static antiquarks and by using tree-level improvement. The resulting potentials provide vague indication for one-pion exchange at $\bar{Q}\bar{Q}$ separations $r⪆$ 0.5 fm.

    ↳ hep-lathep-phPoS(2025)·8 citations
19. 19*

    Probing dark-matter effects with gravitational waves using the parameterized post-Einsteinian framework

    Eileen Wilcox🇺🇸 · David Nichols🇺🇸 · Kent Yagi🇺🇸

    A massive black hole can develop a dark-matter overdensity, and the dark matter changes the evolution of a stellar-mass compact object inspiraling around the massive black hole through the dense dark-matter environment. Specifically, dynamical friction speeds up the inspiral of the compact object and causes feedback on the dark-matter distribution. These intermediate mass-ratio inspirals with dark matter are a source of gravitational waves (GWs), and the waves can dephase significantly from an equivalent system in vacuum. Prior work has shown that this dephasing needs to be modeled to detect the GWs from these systems with LISA (the Laser Interferometer Space Antenna); it also showed that the density and distribution of dark matter can be inferred from a GW measurement. In this paper, we study whether the parametrized post-Einsteinian (ppE) framework can be used to infer the presence of dark matter in these systems. We confirm that if vacuum waveform templates are used to model the GWs from an inspiral in a dark-matter halo, then the resulting parameter estimation is biased. We then apply the ppE framework to determine whether it can reduce the parameter-estimation biases, and we find that adding one ppE phase term to a waveform template eliminates the parameter-estimation biases (statistical errors become larger than the systematic ones), but the effective post-Newtonian order in the ppE framework must be specified without uncertainties. When the post-Newtonian order has uncertainty, we find that the systematic errors on the ppE and the binary's parameters exceed the statistical errors. Thus, the simplest ppE framework would not give unbiased results for these systems, and a further extension of it, or dedicated parameter estimation with gravitational waveforms that include dark-matter effects would be needed.

    ↳ gr-qcastro-ph.COhep-phPRD(2024)·13 citations
20. 20*

    Evaluating Modifications to Classifiers for Identification of Higgs Bosons

    Rishivarshil Nelakurti🇺🇸 · Christopher Hill🇺🇸

    The Higgs boson, discovered back in 2012 through collision data at the Large Hadron Collider (LHC) by ATLAS and CMS experiments, marked a significant inflection point in High Energy Physics (HEP). Today, it's crucial to precisely measure Higgs production processes with LHC experiments in order to gain insights into the universe and find any invisible physics. To analyze the vast data that LHC experiments generate, classical machine learning has become an invaluable tool. However, classical classifiers often struggle with detecting higgs production processes, leading to incorrect labeling of Higgs Bosons. This paper aims to tackle this classification problem by investigating the use of quantum machine learning (QML).

    ↳ hep-exhep-phquant-ph0 citations
21. 21*

    Exploring the Key Features of Repeating Fast Radio Bursts with Machine Learning

    Wan-Peng Sun🇺🇸 · Ji-Guo Zhang🇺🇸 · Yichao Li🇺🇸 · Wan-Ting Hou🇨🇳 · Fu-Wen Zhang🇨🇳 · Jing-Fei Zhang🇺🇸 · Xin Zhang🇺🇸

    Fast radio bursts (FRBs) are enigmatic high-energy events with unknown origins, which are observationally divided into two categories, i.e., repeaters and non-repeaters. However, there are potentially a number of non-repeaters that may be misclassified, as repeating bursts are missed due to the limited sensitivity and observation periods, thus misleading the investigation of their physical properties. In this work, we propose a repeater identification method based on the t-distributed Stochastic Neighbor Embedding (t-SNE) algorithm and apply the classification to the first Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst (CHIME/FRB) catalog. We find that the spectral morphology parameters, specifically spectral running ($r$), represent the key features for identifying repeaters from the non-repeaters. Also, the results suggest that repeaters are more biased towards narrowband emission, whereas non-repeaters are inclined toward broadband emission. We provide a list of 163 repeater candidates, 5 of which are confirmed with an updated repeater catalog from CHIME/FRB. Our findings improve our understanding of the various properties underlying repeaters and non-repeaters, as well as guidelines for future FRB detection and categorization.

    ↳ astro-ph.HEastro-ph.IMgr-qchep-phApJ(2025)·19 citations
22. 22*

    History of a Particle Bounded to the Cosmological LTB Black Hole Surrounded by the Quintom Field

    Sareh Eslamzadeh🇮🇷 · Saheb Soroushfar🇮🇷

    In this paper, we derived the complete set of time-dependent geodesic equations for an LTB black hole surrounded by a Quintom field and investigated the evolution of effective potential and photon orbits across cosmic epochs. Our findings demonstrate that in an accelerated universe, the peak of an effective potential decreases in height and shifts toward smaller radii. Additionally, the probability of stable orbit formation decreases as cosmic expansion progresses. We classified the possible trajectories into four types: terminating bound orbits, stable orbits, scattering flyby orbits, and terminating escape orbits. The results indicate that stable bound orbits are more prevalent in the early universe, whereas at late time epochs, flyby orbits become dominant due to the expansion-driven weakening of gravitational potential. We further analyzed the impact of angular momentum on the evolution of orbits, showing that as it increases, the ISCO radius decreases while the peak of the effective potential shifts outward. This suggests that particles with higher angular momentum follow extended bound orbits, and more energetic photons are more likely to be captured by the black hole. Conversely, an increase in angular momentum reduces the probability of flyby orbits while increasing the likelihood of direct fall into the black hole. Our study provides new insights into how cosmic acceleration influences black hole geodesics, revealing that the progressive shrinking of ISCO and stable orbits eventually disappear as the universe approaches the Big Rip singularity. These findings contribute to a deeper understanding of the dynamical nature of cosmological black holes and may offer new perspectives for observational tests through gravitational lensing, accretion disk evolution, and quasi-periodic oscillations (QPOs) in evolving black hole spacetimes.

    ↳ gr-qchep-phEur.Phys.J.Plus(2025)·0 citations
23. 23*

    Meson mass spectrum in QCD${}_2$ 't Hooft's model

    Alexey Litvinov🇷🇺 · Pavel Meshcheriakov🇷🇺

    We study the spectrum of meson masses in large $N_c$ QCD${}_2$ governed by celebrated 't Hooft's integral equation. We generalize analytical methods proposed by Fateev, Lukyanov and Zamolodchikov to the case of arbitrary, but equal quark masses $m_1=m_2.$ Our results include analytical expressions for spectral sums and systematic large-$n$ expansion. We also study the spectral sums in the chiral limit and the heavy quark limit and find a complete agreement with known results.

    ↳ hep-thhep-phmath-phmath.MPNPB(2025)·23 citations
24. 24*

    Feasibility study of True Muonium discovery with CERN-SPS H4 positron beam

    Ruben Gargiulo🇮🇹 · Elisa Di Meco🇮🇹 · Stefano Palmisano🇮🇹

    True muonium (${\mu }^{+}{\mu }^{-}$) is one of the heaviest and smallest electromagnetic bound states not containing hadrons, and has never been observed so far. In this work it is shown that the spin-1 TM state (ortho-TM) can be observed at a discovery level of significance in three months at the CERN SPS North-Area H4A beam line, using 43.7 GeV secondary positrons. In this way, by impinging the positrons on multiple thin low-Z targets, ortho-TM, which decays predominantly to $e^{+}{e}^{-}$, can be produced from $e^{+}{e}^{-}\to TM$ interactions on resonance ($\sqrt{s}\sim 2m_{\mu }$).

    ↳ hep-exhep-phPRD(2024)·11 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.