Tue·Aug 26, 2025Tuesday·August 26, 2025

1. 01*

   A Journey of Seeking Pressure and Forces in the Nucleon

   Xiangdong Ji🇺🇸 · Chen Yang🇺🇸

   Momentum current density (MCD) $T^{ij}$ is a general physics concept describing the momentum conservation through momentum flow generated from both the kinetic motion of particles and the interacting forces among them. It has been suggested by M. Polyakov et al. that the MCD in the nucleon, characterized by the form factor $C/D$ of the QCD energy-momentum tensor, can be interpreted as the pressure and shear forces between adjacent parts of the system because the nucleon interior approximates a continuous medium. While intuitively appealing, we find that the interpretation is hard to justify from a detailed examination of the physical mechanisms for the momentum flow in QCD. After reviewing through a broad range of classical and quantum systems, we find that while thermal and/or quantum average of isotropic motion contributes to kinetic MCD a pressure term proportional to ${\delta }^{ij}$, when there is an anisotropic motion, the pressure cannot simply be identified from the MCD tensor. Furthermore, kinetic pressure cannot be considered as the surface force between adjacent parts of a system. More importantly, at the scale of the nucleon dimension, the color forces among quarks and gluons is by no means short-ranged as in a continuous medium, and the resulting interaction MCD cannot be interpreted as normal or shear ``stress'' force, although an isotropic term from the QCD trace anomaly may be interpreted as a ``vacuum pressure.'' Following our previous study of force densities through divergences of kinetic MCDs, we affirm that the vacuum pressure term provides a confining potential on the quarks through color Lorentz forces.

   hep-phhep-latnucl-thNPB(2026)·30 citations
2. 02*

   Role of $K_0^{\ast }(700)$ exchange in the $p\bar{p}\to \Lambda \bar{\Lambda }$ reaction

   Hao-Nan Wang🇨🇳 · Cheng Chen🇨🇳 · Xing-Yi Ji🇨🇳 · De-Min Li🇨🇳 · Yue Ma🇯🇵 · En Wang🇨🇳 · Ju-Jun Xie🇨🇳

   Based on the effective Lagrangian approach, we investigate the $p\bar{p}\to \Lambda \bar{\Lambda }$ reaction. Within this framework, we provide a dynamical explanation by analyzing its total and differential cross sections, as well as the polarization of the produced $\Lambda$ hyperon. Incorporating the $t$-channel exchange of the scalar $K_0^{\ast }(700)$ and pseudoscalar $K$ mesons, complemented by an $s$-channel contribution from the vector excited state, we can reproduce the current experimental data fairly well in a wide energy region. Compared to the conventional $K$ and $K^{\ast }(892)$ mesons exchange, the $K_0^{\ast }(700)$ meson exchange plays a more essential role in simultaneously capturing the observed features of the total and differential cross sections. The introduction of the vector $s$-channel resonance improves the description of the spin observables. This work gives a perspective to inspect the role of $K_0^{\ast }(700)$ and serves as a test to search for the resonances in the reaction $p\bar{p}\to \Lambda \bar{\Lambda }$ at threshold.

   hep-phPRD(2026)·1 citation
3. 03*

   NNLO electron structure functions (PDFs) from SCET

   Maximilian Stahlhofen🇩🇪

   We calculate the electron structure functions, aka parton distribution functions (PDFs), to NNLO in QED. The calculation is based on the definition of the PDFs in terms of operator matrix elements in soft collinear effective theory (SCET) and directly performed in momentum space. The electron PDFs describe the universal effects of collinear initial state radiation (ISR) off the electron (or positron) in DIS or $e^{+}{e}^{-}$ collision events. The parton collinear to the electron that enters the hard scattering process governed by the energy scale $Q$ can be a photon or a (anti)fermion with mass $m_f\sim m_e\ll Q$. Our SCET momentum-space calculation confirms earlier results obtained from a QED computation in Mellin space and extends them by taking more than one massive fermion flavor into account. The well-known factorization of sufficiently inclusive cross sections into PDFs with massive fermions and hard partonic cross sections with massless fermions at leading order in $m_e/Q$ is discussed from the SCET perspective. Analogies to the nonperturbative PDFs and collinear factorization in QCD are pointed out. Based on this factorization DGLAP-type resummation of large logarithms of the ratio $m_e/Q$ is straightforward.

   hep-phhep-thJHEP(2025)·10 citations
4. 04*

   Spontaneous breaking of global U(1) symmetry in an interacting Bose gas under rigid rotation

   E. Siri🇮🇷 · N. Sadooghi🇮🇷

   We investigate the impact of rigid rotation on the spontaneous breaking of U(1) symmetry in a Bose gas, which is described by a self-interacting complex scalar field Lagrangian. Rigid rotation is introduced through a specific metric that explicitly depends on the angular velocity $\Omega$. We begin by determining the free propagator for this model at finite temperature $T$ and chemical potential $\mu$. Using this propagator, we calculate the thermodynamic potential in terms of an energy dispersion relation ${ϵ}_k$. It is found that in both the U(1) symmetric phase and the symmetry-broken phase, two energy branches emerge. In the symmetry-broken phase, they are identified with a massive phonon and a massless roton mode. Notably, rotation does not alter ${ϵ}_k$ at low momentum. Setting $\mu =0$, we use the total thermodynamic potential, which includes classical, thermal, vacuum, and nonperturbative ring contributions, to explore how the condensate depends on $T$ and $\Omega$. We first focus on the classical and thermal parts of the thermodynamic potential and find that the critical temperature of the U(1) phase transition scales as ${\Omega }^{1/3}$. By identifying the (pseudo-)Goldstone and non-Goldstone modes of this model with $\pi$ and $\sigma$ mesons, we calculate the $T$ and $\Omega$ dependence of masses $m_{\pi }$ and $m_{\sigma }$. We demonstrate that the Goldstone theorem holds only when the one-loop (thermal) corrections to $m_{\sigma }$ and $m_{\pi }$ are taken into account. We further explore the $T$ and $\Omega$ dependence of the condensate, determine the $\sigma$ dissociation temperatures for fixed $\Omega$, and compare them with the critical temperature of the phase transition. Additionally, we emphasize the role played by the nonperturbative ring potential, especially in altering the order of the phase transition with and without rotation.

   hep-phcond-mat.quant-gashep-thnucl-th4 citations
5. 05*

   Pinpointing Physical Solutions in Y(4230) Decays

   Jie Yuan🇨🇳 · Yadi Wang🇨🇳 · Kai Zhu🇨🇳

   To resolve ambiguities from multiple solutions in experimental measurements, we construct a ${\chi }^2$ function incorporating constraints such as isospin conservation and amplitude relations. By minimizing the global ${\chi }^2$, we identify physical solutions for seven hidden-charm decay channels of $Y(4230)$. Crucially, the physical solution for $Y(4230)\to {\pi }^{+}{\pi }^{-}J/\psi$ corresponds to the largest among four experimental solutions, potentially modifying inputs for theoretical calculations. Additionally, we predict ${\Gamma }_{ee}B(Y(4230)\to {\pi }^{+}{\pi }^{-}\psi (2S))$ based on our results, acknowledging substantial uncertainties in current measurements.

   hep-phhep-exPRD(2025)·0 citations
6. 06*

   Emergence of Photon Bose-Einstein Condensation from Down-Scattering in Cold Electron Media

   Bing'ang Guo🇨🇳 · Wei Kou🇨🇳 · Xurong Chen🇨🇳

   In this study, we examine the emergence of photon Bose-Einstein condensation (BEC) resulting from the interaction of high-energy photons with a cold electron gas, modeled via a modified Kompaneets equation. Beginning with an initial black-body photon spectrum, we perform numerical simulations to track the evolution of the photon distribution under the influence of inverse Compton scattering, wherein photons dissipate energy through collisions with cold electrons. Our results demonstrate a pronounced enhancement of photon number density at the low-energy tail, indicative of a BEC-like phase transition. This phenomenon is further corroborated by an analysis of the entropy evolution during the cooling process, revealing that the condensate configuration corresponds to the entropy maximum, in accordance with thermodynamic principles. These findings establish a comprehensive theoretical framework for photon BEC formation in cold electron environments and underscore the significance of entropy maximization as a driving mechanism for condensation.

   hep-phcond-mat.quant-gasApJ(2026)·0 citations
7. 07*

   Analysis of the hidden-charm pentaquark candidates in the $J/\psi \Lambda$ mass spectrum via the QCD sum rules

   Zhi-Gang Wang🇨🇳 · Qi Xin🇨🇳

   In this work, we distinguish the isospin for the first time and study the diquark-diquark-antiquark type $udsc\bar{c}$ pentaquark states with zero isospin via the QCD sum rules systematically. We distinguish contributions of the pentaquark states with negative parity from positive parity unambiguously and obtain clean QCD sum rules for the pentaquark states with negative parity. Then we adopt the modified energy scale formula to choose the optimal energy scales of the QCD spectral densities, and obtain the mass spectrum of the $udsc\bar{c}$ pentaquark states with the quantum numbers $I=0$ and $J^P={\frac{1}{2}}^{-}$, ${\frac{3}{2}}^{-}$, ${\frac{5}{2}}^{-}$, which could interpret the $P_{cs}(4338)$ and $P_{cs}(4459)$ in the $J/\psi \Lambda$ mass spectrum naturally.

   hep-phEPJC(2026)·12 citations
8. 08*

   Sensitivity of neutrinoless double beta decays from a combined analysis of ground and excited states

   C. R. Ding🇨🇳 · K. Han🇨🇳 · S.B. Wang🇨🇳 · J. M. Yao🇨🇳

   Next-generation neutrinoless double-beta ($0\nu \beta \beta$) decay experiments, with projected half-life sensitivities approaching $10^{28}$ years, aim to probe the entire parameter space of the inverted neutrino mass ordering in the light-neutrino-exchange scenario. However, this reach remains uncertain by the substantial model dependence of the nuclear matrix elements (NMEs). In this work, we propose a strategy based on a combined analysis of $0\nu \beta \beta$ decays to both the ground state and the first excited $0^{+}$ state of the daughter nucleus. We show that such a multi-channel approach can significantly enhance experimental sensitivity, depending on the underlying NME predictions. This method is particularly well-suited for large liquid xenon detectors, such as the proposed PandaX-xT and XLZD experiments, which can efficiently identify transitions of ${}^{136}$Xe to excited states. Our results highlight the importance of exploiting multiple decay channels in future $0\nu \beta \beta$ searches to maximize their discovery potential.

   hep-phhep-exnucl-exnucl-thPLB(2026)·0 citations
9. 09*

   Probing Leptophobic Dark Sectors via Gravitational Wave Signatures

   Taramati🇮🇳 · Lekhika Malhotra🇮🇳 · Zafri A. Borboruah🇮🇳 · Sudhanwa Patra🇮🇳

   We study a minimally extended version of the Standard Model where baryon number is gauged with a $U(1{)}_B$ symmetry. This model can be made anomaly-free by adding a set of additional fermions. The lightest component of these fermions behaves as a viable dark matter candidate. We show that the spontaneous breaking of $U(1{)}_B$ symmetry can produce gravitational waves via bubble dynamics resulting from a first-order phase transition, which can be detected in future gravitational wave experiments like LISA and ET. Such gravitational wave signatures can be used as a probe to constrain the model in future observations and complement dark matter and collider searches. We perform a random numerical scan of the parameter space and derive the viable region consistent with theoretical bounds from running of the coupling constants, current experimental bounds from dark matter experiments such as LUX-ZEPLIN and XENONnT and sensitive to future gravitational wave experiments. We find that dark matter with mass of 8 - 12 TeV is the most interesting to test in future gravitational wave as well as laboratory experiments. In the viable parameter space, the mass of the $Z^{\prime }$ gauge boson associated with the $U(1{)}_B$ lies in the 16 - 24 TeV range, and the mass of the scalar associated with the symmetry breaking lies around 1 - 2.5 TeV scale. Recent results from LUX-ZEPLIN rules out mass scales below TeV in this model, while dark matter with mass larger than 12 TeV will not be sensitive to future GW experiments. Hence, the dark matter and mediator mass scales of interest are marginally accessible at current collider energies.

   hep-phastro-ph.COPRD(2026)·2 citations
10. 10*

    Investigating topped hadrons to probe the boundaries of the potential model

    Si-Qiang Luo🇨🇳 · Qi Huang🇨🇳 · Xiang Liu🇨🇳

    Inspired by the recent discovery of a pseudoscalar enhancement structure near the $t\bar{t}$ threshold reported by the CMS and ATLAS Collaborations, this work investigates the mass spectra of single topped hadrons-including both topped mesons and topped baryons-based on a relativistic potential model. Using the same parameters obtained from the fit to mesons and baryons, we provide predictions for the mass spectra of ground and low-lying orbitally excited single topped mesons and baryons. In addition, we point out that the precise measurement of the $t\bar{t}$ mass could test the limitation of the potential model. Given the extremely large mass of the topped quark, we discuss spectroscopic properties of topped hadrons in the approximation of an ideal heavy-quark limit.

    hep-phPRD(2026)·10 citations
11. 11*

    Charmonium spectrum and its decay properties

    Zaki Ahmad🇵🇰 · Ishrat Asghar🇵🇰 · Bilal Masud🇵🇰 · M. Atif Sultan🇨🇳

    In this work, we have calculated the mass spectrum, radiative decays, and strong decays of charmonium (cc) by using the non-relativistic quark potential(NRQP) model. The wave functions are calculated by solving the radial Schrodinger equation numerically, which are further used to compute the radiative decay widths of (cc) states. The 3P0 model is used to calculate the strong decay widths by using the simple harmonic (SHO) wave functions. The SHO parameter \b{eta} values for different cc states are calculated by fitting it to the numerical wave functions. We also compare our results with experimental data and other theoretically predicted results. We assign to the charmonium states X(3940), X(3872), X(3862), X(4350) likely quantum numbers of {\eta}c(3S), ḩi}1(2P), ḩi}0(2P) and ḩi}2(3P) states.

    hep-phEPJA(2025)·4 citations
12. 12*

    Rephasing invariant formulae for CP phases in general parameterizations of flavor mixing matrix and exact sum rules with unitarity triangles

    Masaki J. S. Yang🇯🇵

    In this letter, we present rephasing invariant formulae ${\delta }^{(\alpha i)}=\arg [V_{\alpha 1}{V}_{\alpha 2}{V}_{\alpha 3}{V}_{1i}{V}_{2i}{V}_{3i}/V_{\alpha i}^3\det V]$ for CP phases ${\delta }^{(\alpha i)}$ associated with nine Euler-angle-like parameterizations of a flavor mixing matrix. Here, $\alpha$ and $i$ denote the row and column carrying the trivial phases in a given parameterization. Furthermore, we show that the phases ${\delta }^{(\alpha i)}$ and the nine angles ${\Phi }_{\alpha i}$ of unitarity triangles satisfy compact sum rules ${\delta }^{(\alpha ,i+2)}-{\delta }^{(\alpha ,i+1)}={\Phi }_{\alpha -2,i}-{\Phi }_{\alpha -1,i}$ and ${\delta }^{(\alpha -2,i)}-{\delta }^{(\alpha -1,i)}={\Phi }_{\alpha ,i+2}-{\Phi }_{\alpha ,i+1}$ where all indices are taken cyclically modulo three. These twelve relations are natural generalizations of the previous result ${\delta }_{\mathrm{PDG}}+{\delta }_{\mathrm{KM}}=\pi -\alpha +\gamma$.

    hep-phCPC(2026)·10 citations
13. 13*

    Probing charmonia resonances in proton-lead collisions at the LHC

    Sudhansu S. Biswal🇮🇳 · Sushree S. Mishra🇮🇳 · Monalisa Mohanty🇮🇳 · K. Sridhar🇮🇳

    After achieving a successful description of charmonia production in proton-proton (pp) collisions within Non-Relativistic Quantum Chromodynamics (NRQCD) and modified NRQCD (MNRQCD) frameworks, we now extend our study to proton-lead (p-Pb) collisions at the Large Hadron Collider (LHC). In this context, theoretical predictions for the production cross-section, the nuclear modification factor $R_{pPb}$ and forward -to-backward production ratio $R_{FB}$ of $J/\psi$ have been made as a function of transverse momentum and rapidity at the LHC. MNRQCD provides a reasonable agreement with the available LHC data for $J/\psi$ production. Furthermore, using the heavy quark symmetry relation, we have estimated the production cross sections and expected number of events of ${\eta }_c$ and $h_c$ production in both NRQCD and MNRQCD. Notably, the predictions exhibit substantial differences in the integrated cross-sections as well as in the $p_T$ distributions for these states at the LHC, highlighting the importance of further experimental and theoretical studies of these resonances to advance our understanding of quarkonium production.

    hep-phhep-exJ.Subatomic Part.Cosmol.(2026)·0 citations
14. 14*

    Vectorlike $\tau$ production through leptoquarks

    Shruti Dubey🇮🇳 · Nilanjana Kumar🇮🇳 · Tanumoy Mandal🇮🇳 · Subhadip Mitra🇮🇳 · Rachit Sharma🇮🇳

    Numerous phenomenological studies and collider searches have probed for the existence of new physics by looking for signatures of leptoquarks (LQs) or vectorlike leptons (VLLs). We consider a new possibility that can arise in theories with enhanced gauge symmetries: both particles are simultaneously present, and LQ-mediated processes enhance the VLL production at the LHC. We study the effect of non-standard interactions of LQs that contribute to novel production and decay signatures. We obtain the HL-LHC prospects of this framework in the mono-and di-lepton final states, and discuss other potentially relevant channels.

    hep-phhep-ex3 citations
15. 15*

    The ${\Lambda }_b\to \Lambda$ transition form factors in perturbative QCD approach

    Lei Yang🇨🇳 · Jia-Jie Han🇨🇳 · Qin Chang🇨🇳 · Fu-Sheng Yu🇨🇳

    In this work, we investigate the ${\Lambda }_b\to \Lambda$ transition form factors in the perturbative QCD (PQCD) approach, incorporating higher-twist light-cone distribution amplitudes (LCDAs). The resulted form factors show that higher-twist LCDAs are dominant numerically. By combining our PQCD predictions at low-$q^2$ with lattice QCD results at high-$q^2$, $z$-series expansion fits are performed to parametrize the form factors over the full kinematic range. We also provide the prediction for physical observables in the rare decay ${\Lambda }_b\to \Lambda {\mu }^{+}{\mu }^{-}$, including the differential branching fraction, dilepton longitudinal polarization fraction, and forward-backward asymmetries (lepton-side, hadron-side, and combined lepton-hadron). Our obtained form factors are consistent with those in other theoretical methods within the uncertainties.

    hep-phEPJC(2026)·7 citations
16. 16*

    Forward neutrino production and event rates at the Future Circular Collider for hadron collisions

    B. R. Ko🇰🇷 · E. Won🇰🇷

    A proposed future ultra high energy collider such as the Future Circular Collider is expected to produce intense and collimated neutrino beams from weak hadron decays. In this study, we estimate the production yields of such neutrinos from proton-proton collisions at a center-of-mass energy of 100~TeV and an integrated luminosity of 1~ab${}^{-1}$. Based on a hypothetical detector positioned either 0.5~km or 2~km downstream from the interaction point along the beamline, we derive the expected rates of charged current neutrino scattering events and their extension to neutrino energies of up to 50~TeV. We, for the first time, also evaluate the feasibility of observing the experimentally unverified direct production of $W^{\pm }$ bosons from neutrino-nucleus interactions.

    hep-phhep-exPTEP·0 citations
17. 17*

    Unified Gas Heating Constraints on Extended Dark Matter Compact Objects

    TaeHun Kim🇰🇷 · Philip Lu🇰🇷 · Volodymyr Takhistov🇯🇵

    We present the first unified constraints on a broad class of extended dark matter compact objects (EDCOs) from interstellar gas heating. These include axion stars, Q-balls, axion miniclusters, dark fermion stars and primordial black holes surrounded by dark matter halos, which arise in a wide range of theories beyond the Standard Model. As such massive objects traverse the interstellar medium, their gravitational influence generates wakes and, if sufficiently compact, drives accretion flows that heat gas in their vicinity. Our general framework extends standard dynamical friction treatments by incorporating finite-size effects, internal density profiles, gas penetration through objects, and criteria for accretion disk formation. We perform detailed numerical calculations of wake formation and gas heating and apply our results to the Leo T dwarf galaxy, establishing new constraints on the dark matter fraction in EDCOs heavier than a solar mass spanning several orders of magnitude in both mass and abundance.

    hep-phastro-ph.COastro-ph.GAastro-ph.HEJCAP(2026)·5 citations
18. 18*

    Spin Correlations in Dark Photon Searches

    Jonathan L. Feng🇺🇸 · Miša Toman🇺🇸 · Eli Welch🇺🇸

    We investigate the spin correlations between production and decay in the process where dark photons $A^{\prime }$ are produced in pseudoscalar meson decays, for example, ${\pi }^0,\eta \to \gamma A^{\prime }$, and then decay to fermion pairs, $A^{\prime }\to f\bar{f}$. This process is the focus of many experimental searches, but spin correlations are typically ignored. We derive analytic results that allow us to quickly scan parameter space and quantify the error made in neglecting spin correlations. In particular, we define a discrepancy parameter and find that this parameter is always less than $\frac{1}{6\sqrt{3}}\approx 9.6\%$, which provides a rough measure of the size of spin correlation effects. However, these effects may be enhanced or suppressed by cuts in realistic experimental analyses, and so we also consider two representative examples, including current FASER analyses and possible future searches at SHiP. We find that the effects of spin correlations are negligible for existing FASER analyses, but can significantly reduce event rates at upcoming SHiP searches.

    hep-phhep-exPRD(2026)·4 citations
19. 19*

    An Undergraduate Approach to the Quantum Hadrodynamics and the Physics of Neutron Stars

    Luiz L. Lopes🇧🇷

    In this tutorial, I discuss how to model a neutron star from the Quantum Hadrodynamics microscopic approach. After a brief discussion about hydrostatic equilibrium, I discuss the role of each meson of the model and how to calculate the corresponding equation of state and the expected values. Each meson is introduced individually. Its effects are analyzed from both an analytical and a numerical point of view. To explicitly show the effects of a given meson, the coupling constant is varied in an arbitrary range before being fixed to reproduce well-known constraints. This work is intended for late undergraduate students as well as early graduate students. The equation of states is obtained from the statistical mechanics formalism, which is more familiar to students at this stage of their research career, instead of the traditional quantum field theory formalism.

    ↳ nucl-thastro-ph.HEhep-phUniverse(2025)·5 citations
20. 20*

    Disformal interactions in the Dark Sector: From driving Early Dark Energy to confronting cosmological tensions

    Pulkit Bansal (IIT Bombay)🇮🇳 · Joseph P. Johnson (IISER Mohali)🇮🇳 · S. Shankaranarayanan (IIT Bombay)🇮🇳

    The $\Lambda$CDM model faces significant challenges, including an incomplete understanding of the dark sector and persistent tensions in the Hubble constant and the clustering amplitude. To address these issues, we propose a general disformal coupling between dark energy (DE) and dark matter from a field-theoretic action which can generate a rich variety of interactions including conformal and pure-momentum coupling scenarios. Our analysis reveals that a pure disformal coupling naturally produces a unique interacting Early Dark Sector, wherein the interactions with dark matter suppress the Hubble friction on the DE scalar field leading to a kinetic-driven cosmological constant-like behavior at early times followed by its dilution as $a^{-6}$ and eventually leading to a potential-driven epoch characteristic of late-time dark energy. In contrast to existing Early Dark Energy (EDE) models that rely on finely-tuned potentials, the EDE-like behavior, in our framework, is purely a consequence of the disformal coupling paired with the dilution of dark matter, offering a more fundamental and less ad hoc solution to cosmological tensions. This framework also predicts a suppression of power in the CMB temperature spectrum on large angular scales, offering a potential physical explanation for the observed low-$\ell$ anomaly. By deriving these effects from a fundamental action, our work provides a unified, testable alternative to $\Lambda$CDM that can be constrained by next-generation cosmological surveys and gravitational wave observations.

    ↳ astro-ph.COgr-qchep-phPRD(2025)·6 citations
21. 21*

    Baryon Electric Charge Correlation as QCD Magnetometer

    Heng-Tong Ding🇨🇳 · Jin-Biao Gu🇨🇳 · Arpith Kumar🇨🇳 · Sheng-Tai Li🇨🇳

    The detection of strong magnetic fields in peripheral heavy-ion collisions is crucial for observing effects such as the chiral magnetic effect but has proven exceptionally difficult. To address this, we propose the baryon electric charge correlation ${\chi }_{11}^{\mathrm{BQ}}$ and the chemical potential ratio ${\mu }_{\mathrm{Q}}/{\mu }_{\mathrm{B}}$ as sensitive probes of magnetic fields, based on (2+1)-flavor lattice QCD simulations at the physical pion mass. Along the transition line, ${\chi }_{11}^{\mathrm{BQ}}$ and $({\mu }_{\mathrm{Q}}/{\mu }_{\mathrm{B}}{)}_{\mathrm{LO}}$ in Pb-Pb collisions increase by factors of 2.1 and 2.4 at $eB\simeq 8M_{\pi }^2$, respectively. To bridge theoretical predictions with experimental observables, we implement systematic kinematic cuts that emulate detector acceptances of the STAR and ALICE experiments within the hadron resonance gas model. This allows us to construct experimentally relevant proxy observables. Furthermore, we demonstrate that $({\mu }_{\mathrm{Q}}/{\mu }_{\mathrm{B}}{)}_{\mathrm{LO}}$ is also sensitive to the collision system, showing a $1.5$-fold increase from Zr-Zr to Ru-Ru isobar collisions. Our findings offer new insights into thermo-magnetic effects and provide experimentally relevant guidance for the detection of magnetic fields in heavy-ion collisions.

    ↳ hep-lathep-phnucl-exnucl-thEPJ Web Conf.(2026)·2 citations
22. 22*

    Dual axion-like field inflation

    Runchao Huang🇨🇳 · Ruifeng Zheng🇨🇳 · Qiaoli Yang🇨🇳

    Cosmic inflation is one of the most important paradigms in modern cosmology. In its simplest form, inflation is driven by a single inflaton field. However, multi-field inflation has become increasingly attractive because it can solve many theoretical and observational challenges. In this paper, we propose a particular model involving two axion-like fields with simply monodromy-dominated potentials. We demonstrate that this model is consistent with current cosmological observations.

    ↳ astro-ph.COhep-phCommun.Theor.Phys.(2025)·1 citation
23. 23*

    Effects of Geometric configuration in relativistic isobaric collisions at $\sqrt{s_{NN}}=200$ GeV

    Akash Das🇮🇳 · Satya Ranjan Nayak🇮🇳 · B. K. Singh🇮🇳

    In this work, we present a study on the effects of nuclear deformation (${\beta }_2$,${\beta }_3$) and surface diffuseness ($a$) on the charged hadron multiplicity ($N_{\mathrm{ch}}$) and elliptic flow ($v_2$), obtained in symmetric isobaric collisions of ${}_{44}^{96}\mathrm{Ru}+{}_{44}^{96}\mathrm{Ru}$ and ${}_{40}^{96}\mathrm{Zr}+{}_{40}^{96}\mathrm{Zr}$. The two extreme configurations (tip-tip and body-body) were used to determine the correlation between the final state observables and initial geometry using the HYDJET++ model. The octupole deformation parameter (${\beta }_3$) enhances $N_{\mathrm{ch}}$ in central tip-tip Zr+Zr collisions and suppresses it in peripheral ones. In mid-central to peripheral body-body Zr+Zr collisions, ${\beta }_3$ leads to a reduction in charged hadron production. Surface-diffuseness ($a$), along with quadrapole deformation (${\beta }_2$), also shows a significant impact on multiplicity and elliptic flow. The octupole deformation enhances elliptic flow in Zr's body-body collisions. Results are compared with the STAR blind-analysis data where available.

    ↳ nucl-thhep-phEur.Phys.J.Plus(2026)·0 citations
24. 24*

    Crossing the phantom divide in scalar-tensor and vector-tensor theories

    Shinji Tsujikawa🇯🇵

    DESI observations of baryon acoustic oscillations (BAOs), combined with cosmic microwave background (CMB) and type-Ia supernova (SN Ia) data, suggest that the dark energy equation of state $w_{\mathrm{DE}}$ crosses the phantom divide from $w_{\mathrm{DE}}<-1$ to $w_{\mathrm{DE}}>-1$ at low redshifts. In shift-symmetric Horndeski and generalized Proca theories with luminal gravitational-wave speed and no direct couplings to dark matter, we show that such a phantom-divide crossing is generically difficult without theoretical pathologies. Breaking the shift symmetry in Horndeski theories allows this transition. We construct an explicit model with broken shift symmetry, in which the scalar field has a potential in addition to a Galileon self-interaction and a quadratic kinetic term. This model realizes the desired phantom-divide crossing at low redshifts without introducing ghosts and Laplacian instabilities.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2026)·32 citations
25. 25*

    A bi-effect model of muon deflections in air showers

    Si-Zhe Wu🇨🇳 · Chao Zhang🇨🇳 · Ruo-Yu Liu🇨🇳 · Xi-Shui Tian🇨🇳 · Zhuo Li🇨🇳

    Recent progress has shown that the geomagnetic field exerts a more significant impact than expected on the behavior of charged secondary particles in inclined air showers. In this study, we for the first time combine it with atmospheric effects to construct a bi-effect model, aiming to investigate the lateral distribution of particles on the ground plane. Despite the complex physical interactions during the development of air showers, a simple formula can describe the overall deflection of ${\mu }^{\pm }$ and accurately fit the deflection in simulated air showers, thereby validating the hypotheses about these effects in this study. Furthermore, we have obtained the relationship between model parameters and primary particle information for different experimental sites. This new model is highly successful and is promising to provide new insights for improving detector layout design and air shower reconstruction.

    ↳ astro-ph.HEhep-ph0 citations
26. 26*

    Assessing Convergence Patterns Across Modern Nucleon-Nucleon Potentials

    P. J. Millican🇺🇸 · R. J. Furnstahl🇺🇸 · J. A. Melendez🇺🇸 · D. R. Phillips🇺🇸

    The BUQEYE model for correlated effective field theory (EFT) truncation errors assumes a regular pattern of dimensionless coefficients extracted from order-by-order observable calculations. This enables results from lower orders to inform statistical predictions for error estimates of omitted higher orders. We test the model for multiple chiral EFT ($\chi$EFT) nucleon-nucleon (NN) potentials using a suite of six common NN scattering observables represented as functions of relative momentum and scattering angle. First, we flag irregularity in the convergence patterns of potentials with so-called "soft" regulator scales, namely that the sizes of the coefficients in the observables' expansions are mismatched between the even and odd orders. Second, we test the BUQEYE model's assumption of Gaussian process (GP) stationarity against the data and find that the GP's correlation structure as encoded in its length scale is nonstationary: The GP length scale in the angular dimension ${\ell }_{\theta }$ is approximately inversely proportional to the relative momentum of the scattering process. After we remediate this issue by allowing ${\ell }_{\theta }$ to vary with momentum, diagnostics show significant improvement, validating the application of the BUQEYE model after this modification. Third, we find that good performance of the BUQEYE model relies on properly choosing the $\chi$EFT breakdown scale ${\Lambda }_b$. With $m_{\text{eff}}$ held fixed at the physical pion mass we find ${\Lambda }_b=600$--$750$ MeV for various N${}^3$LO interactions. Statistically consistent distributions for ${\Lambda }_b$ across orders are only found for the SMS potential at a regulator scale of 450 or 500 MeV. All our results can be reproduced using a publicly available Jupyter notebook, which can be straightforwardly modified to analyze other $\chi$EFT NN potentials.

    ↳ nucl-thhep-phphysics.data-anPRC(2026)·8 citations
27. 27*

    Calculating the power spectrum in stochastic inflation by Monte Carlo simulation and least squares curve fitting

    Koichi Miyamoto🇯🇵 · Yuichiro Tada🇯🇵

    The stochastic-$\delta \mathcal{N}$ formalism is widely used to study inflation models in which the quantum diffusion of inflatons dominates the background dynamics, leading to interesting phenomena such as the production of primordial black holes. Among numerical approaches to calculate the curvature perturbation spectrum ${\mathcal{P}}_{\zeta }(k)$ in this formalism, the Monte Carlo simulation-based approach has been proposed as a promising choice, especially in multifield cases. In this approach, we generate many paths of inflatons from the initial points to the end of inflation, obtain statistics of $\delta N$ from the paths, and then estimate ${\mathcal{P}}_{\zeta }(k)$. However, this method involves a nested Monte Carlo simulation, which requires generating many branch paths from each trunk path at the point corresponding to the scale $k$ of interest, resulting in a high computational cost. In this paper, we propose a new Monte Carlo-based approach that utilizes least squares fitting, introducing two novel features for reducing computational cost. First, we devise a simple estimator of a key statistic $⟨\delta {\mathcal{N}}_{\mathbf{X}}^2⟩$, the variance of $\delta \mathcal{N}$ conditioned on the branching point, to avoid nesting path generation. Second, via least squares fitting of a parametric function to the sampled values of the estimator, we obtain not just an estimate of ${\mathcal{P}}_{\zeta }(k)$ for a single value of $k$ but an approximating function of ${\mathcal{P}}_{\zeta }(k)$ over a range of $k$ of interest. We also conduct numerical demonstrations for concrete inflation models, which show the usefulness of our method.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2026)·5 citations
28. 28*

    The Impact of Axion-Like Particles on Late Stellar Evolution From Intermediate-Mass Stars to core-collapse Supernova Progenitors

    Inmacolata Domínguez🇪🇸 · Oscar Straniero🇮🇹 · Luciano Piersanti🇮🇹 · Maurizio Giannotti🇪🇸 · Alessandro Mirizzi🇮🇹

    Context. Stars with masses ranging from 3 to 11 M_\odot exhibit multiple evolutionary paths. Less massive stars in this range conclude their evolution as carbon-oxygen (CO) white dwarfs. However, those that achieve carbon ignition before the pressure by degenerate electron halts the core contraction may either form massive CONe/ONe white dwarfs, or undergo an electron-capture supernova, or photo-disintegrate neon and proceed with further thermonuclear burning, ultimately leading to the formation of a gravitationally unstable iron core. Aims. An evaluation of the impact of the energy loss caused by the production of axion-like-particles (ALPs) on evolution and final destiny of these stars is the main objective of this paper. Methods. We compute various sets of stellar models, all with solar initial composition, varying the strengths of the ALP coupling with photons and electrons. Results. As a consequence of an ALP thermal production, the critical masses for off-center C and Ne ignitions are both shifted upward. When the current bounds for the ALP coupling strengths are assumed, the maximum mass for CO WD progenitors is about 1.1 M_\odot heavier than that obtained without the ALP energy loss, while the minimum mass for a core collapse supernova (CCSN) progenitor is 0.7 M_\odot higher. Conclusions. Current constraints from observed Type II-P supernova light curves and pre-explosive luminosity do not exclude an ALP production within the current bounds. However, the maximum age of CCSN progenitors, as deduced from the star formation rate of the parent stellar population, would require a smaller minimum mass. This discrepancy can be explained by assuming a moderate extra mixing (as due to core overshooting or rotational induced mixing) above the fully convective core that develops during the main sequence.

    ↳ astro-ph.SRastro-ph.HEhep-exhep-ph+1Astron.Astrophys.(2025)·3 citations
29. 29*

    Nonlinearities of Schwarzschild Black Hole Head-on Collisions

    Alex Kehagias🇬🇷 · Davide Perrone🇨🇭 · Antonio Riotto🇨🇭

    We derive analytically the amplitude of the quadratic quasi-normal mode generated in the ringdown stage of the gravitational waveform produced by the ultra-relativistic head-on collision of two non-spinning Schwarzschild black holes. Although being a highly nonlinear event, second-order perturbation theory suffices and that nonlinearities may be derived by a simple bootstrapping procedure.

    ↳ gr-qcastro-ph.COhep-phhep-th3 citations
30. 30*

    Generalized Parton Distributions from Lattice QCD with Asymmetric Momentum Transfer: Unpolarized Quarks at Nonzero Skewness

    Min-Huan Chu🇵🇱 · Manuel Colaço🇵🇹 · Shohini Bhattacharya🇺🇸 · Krzysztof Cichy🇵🇱 · Martha Constantinou🇺🇸 · Andreas Metz🇺🇸 · Fernanda Steffens🇩🇪

    We extend the formalism of asymmetric frames of reference for generalized parton distributions (GPDs) to the case of nonzero skewness, i.e., including longitudinal momentum transfer. The framework, based on Lorentz-invariant amplitudes and previously developed and numerically implemented for unpolarized, helicity and transversity GPDs at zero skewness, gives efficient access to a broad range of kinematics, making full mapping of GPDs from the lattice realistic. The general-skewness formalism is tested using lattice data with both transverse and longitudinal or only longitudinal momentum transfer, the latter being a special case with a reduced number of independent amplitudes. We extract the amplitudes in coordinate space and express the GPDs $H$ and $E$ in terms of these amplitudes. This is followed by reconstruction of quasi-distributions and their matching to the light cone. We further identify and discuss the principal challenges for nonzero skewness GPDs.

    ↳ hep-lathep-phPRD(2025)·18 citations
31. 31*

    Precision Measurements of the Electroweak Mixing Angle in the Region of the Z pole

    Arie Bodek🇺🇸 · Hyon-San Seo🇺🇸 · Un-Ki Yang🇰🇷

    We review the current status and techniques used in precision measurements of the effective leptonic weak mixing angle ${\sin }^2{\theta }_{\mathrm{eff}}^{\ell }$ (a fundamental parameter of the Standard Model (SM)) in the region of the Z pole with emphasis on hadron colliders. We also build on these techniques to extract the most precise single measurement to date of ${\sin }^2{\theta }_{\mathrm{eff}}^{\ell }$ from a new analysis of the published forward-backward asymmetry ($A_{\mathrm{FB}}$) in Drell-Yan dielpton production in proton-proton collisions at a center of mass energy of 13 TeV measured by the CMS collaboration at the large hadron collider. The uncertainty in ${\sin }^2{\theta }_{\mathrm{eff}}^{\ell }$ published by CMS is dominated by uncertainties in Parton Distribution Functions (PDFs), which are reduced by PDF profiling using the dilepton mass dependence of $A_{\mathrm{FB}}$. Our new extraction of ${\sin }^2{\theta }_{\mathrm{eff}}^{\ell }$ from the CMS values of $A_{\mathrm{FB}}$ includes profiling with additional new CMS measurements of the $W$-boson decay lepton asymmetry, and W/Z cross section ratio at 13 TeV. We obtain the most precise single measurement of ${\sin }^2{\theta }_{\mathrm{eff}}^{\ell }$ to date of 0.23156$\pm$0.00024, which is in excellent agreement with the SM prediction of 0.23161$\pm$0.00004. We also discuss outlook for future measurements at the LHC including more precise measurements of ${\sin }^2{\theta }_{\mathrm{eff}}^{\ell }$, a measurement of ${\sin }^2{\theta }_{\mathrm{eff}}^{\ell }$ for b-quarks in the initial state, and a measurement of the running of ${\sin }^2{\theta }^{\overline{\mathrm{MS}}}(\mu )$ up to 3 TeV.

    ↳ hep-exhep-phhep-th3 citations
32. 32*

    Timing Mass of the Local Group

    Louis E. Strigari🇺🇸

    The classic model of the Local Group (LG) is that of two dominant constituents, the Milky Way and M31, first separating and then detaching from the Hubble flow, leading to a nearly radial approaching orbit. This simple model has been confronted by new measurements of the 3D M31 kinematics, by cosmological simulations, and by theoretical understanding of the impact of massive substructures such as the Large Magellanic Cloud. This article explores the consequences of new observations and theory on the determination of the mass and dynamics of the LG. The M31 tangential velocity measurement and contribution from the cosmological constant both increase the implied timing mass of the LG to be $\sim 5\times 10^{12}$ M${}_{\odot }$. Timing mass estimates for the LG tend to be larger than the sum of the Milky Way and M31 halo masses, and larger than independent LG mass estimators. Precision future kinematics have the potential to explore the origin of this difference, shed light on dark matter in the LG, the origin of its angular momentum, and possibly even local values of cosmological parameters.

    ↳ astro-ph.COastro-ph.GAhep-phAnn.Rev.Astron.Astrophys.(2025)·5 citations
33. 33*

    Searching non-standard interactions with atmospheric neutrinos at ESSnuSB

    ESSnuSB: J. Aguilar🇪🇸 · M. Anastasopoulos🇸🇪 · D. Barčot🇭🇷 · E. Baussan🇫🇷 · A. K. Bhattacharyya🇸🇪 · A. Bignami🇸🇪 · M. Blennow🇸🇪 · M. Bogomilov🇧🇬 · B. Bolling🇸🇪 · E. Bouquerel🇫🇷 · F. Bramati🇮🇹 · A. Branca🇮🇹 and 80 other authors

    Atmospheric neutrinos provide a unique avenue to study neutrino interactions in matter. In this work, the prospects of constraining non-standard neutrino interactions with atmospheric neutrino oscillations are investigated for the proposed ESSnuSB far detector. By analyzing atmospheric neutrino samples equivalent to 5.4 Mt$\cdot$year exposure, it is found that ESSnuSB could be able to set the upper bounds $|{ϵ}_{e\mu }^m|<0.053,|{ϵ}_{e\tau }^m|<0.057,|{ϵ}_{\mu \tau }^m|<0.021,{ϵ}_{ee}^m-{ϵ}_{\mu \mu }^m<0.075$ and $|{ϵ}_{\tau \tau }^m-{ϵ}_{\mu \mu }^m|<0.031$ at $90\%$ CL, when the results are minimized for ${\varphi }_{e\mu }^m,{\varphi }_{e\tau }^m$ and ${\varphi }_{\mu \tau }^m$ and normal ordering is assumed for neutrino masses. It is also shown that the presence of non-standard interactions could affect the sensitivities to neutrino mass ordering and ${\theta }_{23}^{}$ octant in comparison to the standard interaction scheme. The results of this work highlight the complementarity between atmospheric and accelerator neutrino programs in ESSnuSB.

    ↳ hep-exhep-phJHEP(2026)·3 citations
34. 34*

    Two-flavored heavy mesons' nuclear bound states

    G. N. Zeminiani🇧🇷 · S. L. P. G. Beres🇧🇷 · K. Tsushima🇧🇷

    We calculate the $B_c$- and $B_s$-nucleus bound state energies and coordinate space radial wave functions by solving the Klein-Gordon equation in momentum space. The attractive strong potentials for the $B_c$ and $B_s$ mesons in nuclei are calculated from the respective mass shifts of these mesons in nuclear matter using a local density approximation. This negative mass shift may be regarded as a signature of partial restoration of chiral symmetry in medium in an empirical sense, because the origin of the negative mass shift in the present study is not directly related to the chiral symmetry mechanism.

    ↳ nucl-thhep-exhep-phnucl-exPoS(2026)·0 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.