Tue·Dec 10, 2024Tuesday·December 10, 2024

1. 01*

   QCD Chemistry: Remarks on Diquarks

   M. Shifman🇺🇸

   In connection with recent discoveries of heavy-quark containing exotic states publications discussing $Qq$ diquarks ($Q,q$ stand for a heavy and light quarks, respectively) proliferated in the literature. After a brief summary of the diquark concept I review various general reasons why the $Qq$ diquark (with sufficinetly heavy $Q$) does not exist. Then I argue (this is the focus of my talk) that the most direct way to confirm non-existence of the $Qq$ diquarks is the study of pre-asymptotic corrections in the inclusive decays of $Qqq$ baryons, e.g. ${\Lambda }_b$. Since the $c$ quarks are much lighter than $b$, namely, $m_b^2/m_c^2\sim 11$, traces of the $cq$ attraction in the color anti-triplet spin-0 state may or may not be present in the $cqq$ baryons.

   hep-phNucl.Part.Phys.Proc.(2024)·5 citations
2. 02*

   Recursion for Differential Cross-Section from the Optical Theorem

   Vatsal Garg🇮🇳 · Hojin Lee🇰🇷 · Kanghoon Lee🇰🇷

   We present a novel framework for computing differential cross-sections in quantum field theory using the optical theorem and loop amplitudes, circumventing the traditional method of squaring scattering amplitudes. This approach addresses two major computational challenges in high-multiplicity processes: complexity from amplitude squaring and the extensive summations over color and helicity. Our method employs quantum off-shell recursion, a loop-level generalization of Berends--Giele recursion, combined with Veltman's largest time equation (LTE) through a doubling prescription of fields. By deriving Dyson--Schwinger equations within this doubled framework and constructing quantum perturbiner expansions, we develop recursive relations for generating LTEs. We validate our method by successfully reproducing the differential cross-section for tree-level $2\to 2$ and $2\to 4$ scalar scattering for ${\varphi }^4$ theory through one-loop and three-loop amplitude calculation respectively. This framework offers an efficient alternative to conventional methods and can be broadly applied to theories with color charges, such as QCD and the Standard Model.

   hep-phhep-th2 citations
3. 03*

   Populating dark sectors with relativistic bubble walls

   Miguel Vanvlasselaer🇧🇪

   In this talk, we present a mechanism of Dark Matter production during first order phase transitions and happening via the collision of the bubble wall and plasma quanta. We will first study the possibility that the dark matter is produced via a renormalisable operator. We will observe that in this context the DM can be much heavier than the scale of the phase transition and has a large initial velocity, leading to the possibility of the DM to be warm today. We will then turn to more realistic scenarios where the Dark Matter sector is secluded and its interaction with the visible sector (including the Standard Model) originates from dimension-five and dimension-six operators. In this regime, we also find that such DM is typically heavy and warm today. We study separately the cases of weakly and strongly coupled dark sectors, where, in the latter case, we focus on glueball DM, which turns out to have very distinct phenomenological properties. For completeness, we also systematically compute the Freeze-In production of the dark sector and compare it with the bubble-plasma DM abundances. All the analytical results are collected in a table presented in this paper.

   hep-phPoS(2025)·1 citation
4. 04*

   On the quarkonium-in-jet collinear fragmentation at moderate-to-large transverse momentum

   Francesco Giovanni Celiberto🇪🇸

   We report progress on the Heavy-Flavor Non-Relativistic Evolution (HF-NRevo) setup, a novel methodology to address quarkonium formation within the fragmentation approximation. Our study sheds light on the moderate to large transverse-momentum sector, where the leading-twist collinear fragmentation of a single parton prevails over the higher-twist fragmentation from a constituent heavy-quark pair produced in the hard scattering. As for the initial energy-scale inputs, we rely on nonrelativistic next-to-leading calculations for all the parton-to-quarkonia fragmentation channels. Preliminary sets of variable-flavor number-scheme (VFNS) fragmentation functions, named NRFF1.0, are built via an evolution-threshold enhanced DGLAP scheme. Taking NRFF1.0 as a starting point, we use HF-NRevo to address the collinear fragmentation of quarkonia inside jets.

   hep-phhep-exnucl-exnucl-thActa Phys.Polon.Supp.(2025)·15 citations
5. 05*

   An effective field theory for muon conversion and muon decay-in-orbit

   Duarte Fontes🇩🇪 · Robert Szafron🇺🇸

   Muon conversion is one of the best probes of charged lepton flavor violation. The experimental limit is soon expected to improve by four orders of magnitude, thus calling for precise predictions of the shape of the signal spectrum. Equally important are precise predictions for muon decay-in-orbit, the main background for muon conversion. While the calculation of electromagnetic corrections to the two processes above the nuclear scale does not involve significant challenges, it becomes substantially more complex below that scale due to multiple scales, bound-state effects and experimental setup. Here, we present a systematic framework that addresses these challenges by resorting to a series of effective field theories. Combining Heavy Quark Effective Theory (HQET), Non-Relativistic QED (NRQED), potential NRQED, Soft-Collinear Effective Theory I and II, and boosted HQET, we derive a factorization theorem and present the renormalization group equations. Our framework allows for the proper calculation of precise predictions for the rates of the two processes, with crucial implications for the upcoming muon conversion searches. We also provide the most accurate prediction of the signal shape for those searches.

   hep-phJHEP(2025)·10 citations
6. 06*

   Oscillatory properties of strange quark stars described by the vector MIT bag model

   Luiz L. Lopes🇧🇷 · Jose C. Jimenez🇧🇷 · Luis B. Castro🇧🇷 · Cesar V. Flores🇧🇷

   We investigated the radial and non-radial fundamental ($f$) mode oscillations of self-bound (quark) stars obtained after employing the Vector MIT (vMIT) bag model. Within this model, we computed the equation of state for strange quark matter satisfying thermodynamic consistency. This allowed us to obtain the corresponding behavior of the speed of sound, mass-radius relation, and gravitational redshift. In particular, our choice of $G_V$ = 0.30 fm${}^2$ produces masses and radii in agreement with recent astronomical data (e.g. from NICER and HESS J1731). In fact, we tested that variations of the remaining vMIT parameters slightly modify this conclusion. Then, we proceeded to compute the radial oscillation frequencies of the $f$-mode, which is tightly connected to the dynamical stability of these compact stars. We found that increments of the $G_V$ parameter have a stabilizing property around the maximal-mass stars for a given stellar family. We also calculated the gravitational-wave frequencies of the non-radial $f$-mode. Our results show that they are restricted to be in the range (1.6 - 1.8) kHz for high-mass stars and to (1.5 - 1.6) kHz for low-mass stars. Finally, we propose a universal relation between these frequencies and the square root of the average density. All these last results are important in distinguishing strange stars from ordinary neutron stars in future gravitational-wave detections coming from compact sources with activated non-radial modes.

   hep-phEPJC(2025)·7 citations
7. 07*

   Neutrino models with a zero mass eigenvalue

   Daijiro Suematsu🇯🇵

   Absolute values of the neutrino mass are not known still now although their upper bounds are constrained through several experiments and observations. Recent analyses of cosmological observations present severe constraint on the sum of neutrino masses. It might suggest an interesting possibility for the absolute values of neutrino mass and their ordering. In this paper, taking it as a useful hint, we study possible neutrino models with a zero mass eigenvalue from a view point of neutrino oscillation data and baryon number asymmetry in the Universe. We focus our study on the seesaw type mass generation by making a certain assumption for origin of right-handed neutrino mass.

   hep-phEPJC(2025)·2 citations
8. 08*

   The Sivers asymmetry of vector meson production in semi-inclusive deep inelastic scattering

   Yongjie Deng🇨🇳 · Tianbo Liu🇨🇳 · Ya-jin Zhou🇨🇳

   The transverse single-spin asymmetry for ${\rho }^0$ production in semi-inclusive deep inelastic scattering was recently reported by the COMPASS Collaboration. Using the Sivers functions extracted from pion and kaon productions, we perform a calculation of the Sivers asymmetry within the transverse momentum dependent factorization. Our results are consistent with the COMPASS data, confirming the universality of the Sivers functions within current experimental uncertainties. While various global analyses of Sivers functions can equally well describe the current data, we obtain very different predictions on the Sivers asymmetry of $\rho$ and $K^{\ast }$ productions at electron-ion colliders, which therefore are expected to provide further constraints.

   hep-phChin.Phys.Lett.(2025)·1 citation
9. 09*

   Research of Extra Charged Gauge Boson $W^{\prime }$ in Alternative Left-Right Model at Future Muon Collider

   Liuxin Zhao🇨🇳 · Honglei Li🇨🇳 · Zhi-Long Han🇨🇳 · Fei Huang🇨🇳 · Xinyi Yan🇨🇳

   The study of extra charged gauge boson beyond the Standard Model has always been of great interest. Future muon colliders will have a significant advantage in discovering exotic particles. In this paper, by studying the ${\mu }^{+}{\mu }^{-}\to W^{\prime +}{W}^{\prime -}\to e^{+}{e}^{-}{n}_e{\bar{n}}_e$ process, we explore the properties of $W^{\prime }$ in the alternative left-right model. The cross section and angular distribution of the final electron are investigated in the scenario of different $W^{\prime }$ mass and right-handed coupling constant. The forward-backward asymmetry is also an important observable to reflect the properties of $W^{\prime }$. We provide a method to effectively suppress the background processes. With specific kinematic cuts, the significance can reach $5.17\sigma$ for 4.8 TeV $W^{\prime }$ at the collision energy of 10 TeV.

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

    Investigation of Mass and Decay Characteristics of the Light-Strange Tetraquark

    Chetan Lodha🇮🇳 · Ajay Kumar Rai🇮🇳

    Motivated by recent developments in tetraquark studies, we investigate the mass spectra and decay properties of light-strange tetraquarks ($sq\bar{s}\bar{q},ss\bar{q}\bar{q}$) in diquark-antidiquark formalism. By considering different internal quark structures and internal color structures, mass spectra are generated in semi-relativistic and non-relativistic frameworks. For decay widths, the annihilation model and spectator model have been incorporated. Several resonances have been explored as potential candidates for these tetraquarks. Concurrently, mass spectra and several decay channels of kaons ($s\bar{q},q\bar{s}$) are also investigated. This study is carried out in the hope of helping improve the understanding of tetraquarks in the light-light sector.

    hep-phIndian J.Phys.(2025)·9 citations
11. 11*

    Shedding light on the intrinsic transversal momentum distributions of pion and kaon

    Jian Chai🇨🇳 · Shan Cheng🇨🇳

    We propose to introduce the intrinsic transversal momentum distribution functions (iTMDs), in conjunction with the light-cone distribution amplitudes (LCDAs), to elucidate the probability amplitude of encountering a meson state wherein the partons swiftly traverse along the longitudinal axis while gently oscillating in the transversal plane. The primary motivation stems from the oversight of soft transverse dynamics within the $k_T$ factorization formalism of an exclusive QCD process, which confines perturbative QCD (pQCD) predictions to scenarios involving large momentum transfers. We meticulously investigate the $\pi$ and $K$ electromagnetic form factors using the iTMDs-improved pQCD calculation at next-to-leading order. By analyzing data in the timelike physical regions, we obtain the transversal-size parameters ${\beta }_{\pi }^2=0.51\pm 0.04$ GeV${}^{-2}$ and ${\beta }_K^2=0.30\pm 0.05$ GeV${}^2$. We then extract the chiral mass of pion to be $m_0^{\pi }(1\mathrm{GeV})=1.84\pm 0.07$ GeV and explain the precise measurements of kaon form factor in the perturbative timelike region. As a remarkable byproduct, we found that the incorporation of iTMDs improves the pQCD predictions for electromagnetic form factors, extending the applicable range to a few GeV${}^2$. This improvement allows for direct comparison with existing measurements and lattice QCD evaluations.

    hep-phPRD(2025)·7 citations
12. 12*

    Axion-photon-mixing dark matter conversion mediated by torsion mass constrained by the Barbero-Immirzi parameter

    Zhi-Fu Gao (1)🇨🇳 · Luiz C. Garcia de Andrade (2) ((1) Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi, Xinjiang, (2) Departamento de Fisica Teorica-IFADT-UERJ, Brasil and Institute for Cosmology and natural philosophy at Croatia)🇧🇷

    In the Standard Model\,(SM) of particle physics, photon-torsion mixing is extended to include the Einstein-Cartan portal to dark-photon-axion-torsion mixing beyond the Standard Model\,(BSM), mediated by torsion. The Barbero-Immirzi(BI) parameter, of the order of $10^{-31}$, is more stringent than those obtained by Aliberti and Lambiase using matter-antimatter asymmetry. This paper presents the coupling of the SM with dark matter\,(DM) axions, both mediated by torsion. We discuss tordions, the quanta of torsion, and the damping of propagating torsion. It is shown that with both kinds of vectorial torsion masses, equations from Einstein-Cartan-Holst gravity can be derived, which reduce to axionic photon equations where torsion appears only through its mass spectrum. Photon-axion conversions and axion mixing are found to depend on the BI parameter. This study demonstrates that when the spin-0 torsion mass is finite and Proca electrodynamics is not ghost-free, dark axion masses align with spin-0 torsion masses via axion-driven torsion and photon-torsion mixing. Our results provide innovative insights into Proca gravity models and the role of torsion in photon-axion conversion and dark matter dynamics, thereby offering a solid foundation for future research and new theoretical frameworks in quantum gravity.

    hep-phgr-qc4 citations
13. 13*

    $V_{cb}$ puzzle in semi-leptonic $B\to D^{\ast }$ decays revisited

    Shuang-Yi Li · Jie Xu · Rui-Xiang Shi · Li-Sheng Geng · Yi Zhang

    Inspired by the newly reported $B\to D^{\ast }(\to D\pi )\ell {\bar{\nu }}_{\ell }$ differential decay rates by the Belle and Belle II Collaborations, we revisit the $V_{cb}$ puzzle in semi-leptonic $B\to D^{\ast }$ decays, considering the latest lattice QCD~(LQCD) simulations and light-cone sum rule~(LCSR) results. We examine the commonly used Caprini-Lellouch-Neubert~(CLN), Boyd-Grinstein-Lebed~(BGL), and heavy quark effective theory~(HQET) parameterizations. We demonstrate that these three parameterizations yield consistent results and reconfirm the $V_{cb}$ puzzle. Then, we use a state-of-the-art Bayesian method to estimate the impact of higher-order terms beyond the present HQET expansion on the uncertainty of $V_{cb}$. We show that higher-order effects cannot eliminate the deviation between the exclusive and inclusive determinations of $V_{cb}$. Finally, utilizing the best-fit results obtained in the HQET parameterization via fitting LQCD and LCSR data only as inputs, we predict the relevant observables, i.e., $R_{D^{\ast }}$, $F_L^{D^{\ast }}$, and $P_{\tau }^{D^{\ast }}$, sensitive to new physics in the $B\to D^{\ast }\ell {\bar{\nu }}_{\ell }$ decays. We conclude that lepton-flavour universality violations still exist in the $b\to c\tau \nu$.

    hep-phhep-exEPJC(2025)·6 citations
14. 14*

    Exploring Anomalous Flavor-Changing Neutral tqh Transitions at Future Muon Colliders: Insights from ${\mu }^{+}{\mu }^{-}\to t\bar{q}h$ Interactions

    Eda Alici🇹🇷

    Flavour-changing neutral current (FCNC) interactions between the Higgs boson and the top quark are subject to significant suppression within the Standard Model (SM). Consequently, these interactions can only attain an observable level through the influence of Beyond the Standard Model (BSM) physics effects. It is therefore of great importance to investigate these rare interactions, both to test the limits of the Standard Model and to reveal new physical signatures.In this context, the present study analyses the signal of the process ${\mu }^{+}{\mu }^{-}\to t\bar{q}h$ and the background processes $t\bar{t}$, $tW\bar{b}$, $WWh$ and $WW$ at both in $\sqrt{s}=1$ TeV and $\sqrt{s}=3$ TeV energy levels. Analyses at the $1TeV$ energy level reveal the observability of FCNC interactions even at low energy conditions and achieve the limit $\text{Br}(t\to qH)=1.96\times 10^{-4}$. This result corresponds to an improvement of approximately 1.5 times compared to the current limits of the ATLAS experiment, which are $3.0\times 10^{-4}$. On the other hand, at the 3 TeV energy level, the most stringent limit was calculated under the luminosity $\mathcal{L}=20a{b}^{-1}$ , yielding a value of $\text{Br}(t\to qH)=1.1\times 10^{-4}$. This result coincides an improvement of approximately 3 times with respect to the current ATLAS experimental limits. The findings of the study underscore the potential of muon colliders in the search for new physics and the pivotal role they can play in the study of rare processes such as Higgs-top quark interactions. Consequently, the results are expected to provide a crucial foundation for both experimental and theoretical studies and to make a significant contribution to the search for BSM physics.

    hep-phEur.Phys.J.Plus(2025)·1 citation
15. 15*

    Quasiparticle second-order dissipative hydrodynamics at finite chemical potential

    Asaad Daher🇵🇱 · Leonardo Tinti🇵🇱 · Amaresh Jaiswal🇮🇳 · Radoslaw Ryblewski🇵🇱

    We extend the derivation of second-order relativistic viscous hydrodynamics to incorporate the effects of baryon current, a non-vanishing chemical potential, and a realistic equation of state. Starting from a microscopic quantum theory, we employ a quasiparticle approximation to describe the evolution of hydrodynamic degrees of freedom and establish its connection to the Wigner formalism. Using methods from relativistic kinetic theory, we perform a second-order expansion to derive a closed set of equations for the components of the stress-energy tensor and the baryon current. The resulting transport coefficients, which depend on the equation of state, are obtained through a unified prescription that ensures thermodynamic consistency.

    hep-phnucl-thPRD(2025)·5 citations
16. 16*

    Mapping spatial distributions within pseudoscalar mesons

    K. Raya🇪🇸 · A. Bashir🇲🇽 · J. Rodríguez-Quintero🇪🇸

    Several aspects of the internal structure of pseudoscalar mesons, accessible through generalized parton distributions in their zero-skewness limit, are examined. These include electromagnetic and gravitational form factors related to charge and mass densities; and distributions in the impact parameter space. To this end, we employ an algebraically viable framework that is based upon the valence-quark generalized parton distribution expressed explicitly in terms of the associated distribution function and a profile function that governs the off-forward dynamics. The predominantly analytical nature of this scheme yields several algebraic results and relations while also facilitating the exploration of insightful limiting cases. With a suitable input distribution function, guided either by experiment or theory, and with an appropriate choice of the profile function, it is possible to provide testable predictions for spatial distributions of valence quarks inside pseudoscalar mesons. When comparison is possible, these predictions align well with existing experimental data as well as the findings of reliable theoretical approaches and lattice QCD.

    hep-phnucl-thChin.Phys.Lett.(2025)·9 citations
17. 17*

    Probing a 2HDM Type-I light Higgs state via $H_{\mathrm{SM}}\to hh\to b\bar{b}\gamma \gamma$ at the LHC

    A. Arhrib🇲🇦 · S. Moretti🇬🇧 · S. Semlali🇬🇧 · C.H. Shepherd-Themistocleous🇬🇧 · Y. Wang🇨🇳 · Q.S. Yan🇨🇳

    We study the discovery potential for a light Higgs boson via $gg\to H_{\text{SM-like}}\to hh\to b\bar{b}\gamma \gamma$ process at the Large Hadron Collider (LHC). Focusing on the 2-Higgs Doublet Model (2HDM) Type-I, which can accommodate light neutral Higgs states, of $\mathcal{O}(100)$ GeV or less in mass, while agreeing with theoretical and up-to-date experimental constraints, we explore the feasibility of a light CP-even Higgs state $h$ via the largely unexplored final state $b\bar{b}\gamma \gamma$ at Run-3 of the LHC. We further propose a few Benchmark Points (BPs) for future searches.

    hep-phPRD(2025)·3 citations
18. 18*

    Ultralight axion or axion-like particle dark matter and 21-cm absorption signals in new physics

    C.R. Das🇷🇺

    A hypothetical particle known as the axion holds the potential to resolve both the cosmic dark matter riddle and particle physics' long-standing, strong CP dilemma. An unusually strong 21-cm absorption feature associated with the initial star formation era, i.e., the dark ages, may be due to ultralight axion dark matter ($\sim$10${}^{-22}$ eV) at this time. The radio wave observation's 21-cm absorption signal can be explained as either anomalous baryon cooling or anomalous cosmic microwave background photon heating. Shortly after the axions or axion-like particles (ALPs) thermalize among themselves and form a Bose--Einstein condensate, the cold dark matter ALPs make thermal contact with baryons, cooling them. ALPs are thought to be the source of some new evidence for dark matter, as the baryon temperature at cosmic dawn was lower than predicted based on presumptions. The detection of baryon acoustic oscillations is found to be consistent with baryon cooling by dark matter ALPs. Simultaneously, under the influence of the primordial black hole and/or intergalactic magnetic fields, the dark radiation composed of ALPs can resonantly transform into photons, significantly heating up the radiation in the frequency range relevant to the 21-cm tests. When examining the 21-cm cosmology at redshifts $z$ between 200 and 20, we see that, when taking into account both heating and cooling options at the same time, heating eliminated the theoretical excess number of neutrino species, $\Delta N_{\mathrm{eff}}$, from the cooling effect.

    hep-phPhys.Atom.Nucl.(2025)·0 citations
19. 19*

    Dark photons and axion-like particles at the Electron-Ion Collider in China

    Qiyuan Gao🇨🇳 · Dan Lin🇨🇳 · Hongkai Liu🇮🇱 · Teng Ma🇨🇳

    The Electron-Ion Collider in China (EicC), a proposed high-luminosity facility with advanced charged particle and photon detection capabilities, provides unique opportunities to uncover new physics beyond the Standard Model. We analyze its sensitivity to dark photons produced through electron bremsstrahlung in coherent scattering. Thanks to its beam energy settings, it has the potential to comprehensively probe the previously unexplored parameter space between the constraints from meson decays and beam dumps below $\mathcal{O}(1)$ GeV with displaced-vertex search. Additionally, the EicC has the potential to probe axion-like particles (ALPs) in the mass range $0.1\text{GeV}\lesssim m_a\lesssim 5\text{GeV}$, with a coupling reach of $\Lambda \lesssim 10^6\text{GeV}$ , by combining the prompt-decay and displaced-vertex searches. The projected sensitivities to ALPs exceed the current bounds.

    hep-phJHEP(2025)·12 citations
20. 20*

    Triple $Z^{\prime }$ signatures at $Z$ factories

    Takaaki Nomura🇨🇳 · Kei Yagyu🇯🇵

    We discuss triple $Z^{\prime }$ boson signatures via the decay chain of $Z\to Z^{\prime }\varphi \to Z^{\prime }{Z}^{\prime }{Z}^{\prime }$, with a new light scalar $\varphi$, at future Z factories such as CEPC and FCC-ee. These new bosons $\varphi$ and $Z^{\prime }$ naturally appear in models with a new $U(1)$ gauge symmetry which is spontaneously broken and introduced in various new physics scenarios. The branching ratio of $Z\to Z^{\prime }\varphi \to Z^{\prime }{Z}^{\prime }{Z}^{\prime }$ can be larger than $10^{-12}$, which gives $O(1)$ events at Tera-Z experiments, when a product of $g_X^{}$ (new gauge coupling) and $\zeta$ ($Z$-$Z^{\prime }$ mixing) is larger than around $10^{-6}$. We find that the search for $Z\to Z^{\prime }{Z}^{\prime }{Z}^{\prime }$ can significantly improve the current bound on a kinetic mixing parameter $ϵ$ in the dark photon case, where $ϵ\gtrsim 10^{-6}$ with $g_X^{}=\mathcal{O}(1)$ can be explored at Tera-Z experiments. We also show that a sufficiently large number of events with multi-lepton plus hadronic jets can be obtained in benchmark points, which cannot be realized by the usual decay of Z in the standard model.

    hep-phhep-exPRD(2025)·1 citation
21. 21*

    Chiral phase transition and spin alignment of vector mesons with chiral imbalance in a rotating QCD medium

    Yang Hua🇨🇳 · Sheng-Qin Feng🇨🇳

    We study the two-flavor NJL model under the rotation and chiral chemical potential ${\mu }_5$. Firstly, the influence of chiral imbalance on the chiral phase transition in the $T_{pc}-\omega$ plane is investigated. Research manifests that as ${\mu }_5$ increases, the critical point (CEP) of the $T_{pc}-\omega$ plane chiral phase transition will move closer to the $T$ axis. This means that the chiral chemical potential ${\mu }_5$ can significantly affect the $T_{pc}-\omega$ phase diagram and phase transition behavior. While discussing the $T_{pc}-\omega$ phase diagram, we also study the spin alignment of the $\rho$ vector meson under rotation. In the study of the spin alignment of the vector meson $\rho$, ${\rho }_{00}$ is the $00$ element of the spin density matrix of vector mesons. At high temperatures, ${\rho }_{00}$ is close to $1/3$, it indicates that the spin alignment of the vector meson $\rho$ is isotropic. It is found that increasing the chiral chemical potential ${\mu }_5$ significantly enhances ${\rho }_{00}$, and makes ${\rho }_{00}$ approaching to $1/3$ around the phase transition temperature. When rotational angular velocity is zero, ${\rho }_{00}$ is close to $1/3$, but as $\omega$ increases, ${\rho }_{00}$ significantly decreases, and deviates $1/3$, indicating that rotation can significantly cause polarization characteristics. The ${\rho }_{00}-r$ relationship near the phase transition temperature is studied. It is found that the farther away from the center of rotation, the lower the degree of spin polarization of the system. It is also found that the influence of chiral imbalance on the ${\rho }_{00}-r$ relationship is also significant.

    hep-phPRD(2025)·9 citations
22. 22*

    Discovery potential of charmonium $2P$ states through the $e^{+}{e}^{-}\to \gamma D\bar{D}$ processes

    Tian-Le Gao🇨🇳 · Ri-Qing Qian🇨🇳 · Xiang Liu🇨🇳

    In this work, we investigate the production of charmonium $2P$ states via the $e^{+}{e}^{-}\to \gamma D\bar{D}$ process at $\sqrt{s}=4.23$ GeV. Using the measured cross-section data for $e^{+}{e}^{-}\to \gamma X(3872)$ as a reference, we calculate the cross sections for $e^{+}{e}^{-}\to \gamma {\chi }_{c0}(2P)$ and $e^{+}{e}^{-}\to \gamma {\chi }_{c2}(2P)$. Since the ${\chi }_{c0}(2P)$ and ${\chi }_{c2}(2P)$ states predominantly decay into $D\bar{D}$ final states, we also predict the corresponding $D\bar{D}$ invariant mass spectrum for the $e^{+}{e}^{-}\to \gamma D\bar{D}$ process. Our results indicate that $e^{+}{e}^{-}\to \gamma D\bar{D}$ is an ideal process for identifying the ${\chi }_{c0}(2P)$ and ${\chi }_{c2}(2P)$ states, analogous to the $\gamma \gamma \to D\bar{D}$ and $B^{+}\to D^{+}{D}^{-}{K}^{+}$ processes. This study highlights the discovery potential of charmonium $2P$ states at BESIII and Belle II.

    hep-phhep-exPRD(2025)·6 citations
23. 23*

    Dark-matter induced neutron-antineutron oscillations

    Théo Brugeat🇫🇷 · Christopher Smith🇫🇷

    If dark matter carries a baryon number of two, neutron-antineutron oscillations could require its presence to manifest themselves. If it is in addition very light, in the micro-eV range or up to a few orders of magnitude below, these oscillations could even exhibit a Rabi resonance. Though the magnetic tuning required to convert a macroscopic number of neutrons into antineutrons is not realistic, sizeable enhancements remain possible. Building on this observation, axionic realizations for this scenario are systematically analyzed. For true QCD axion models, we find that the Goldstone boson nature of the axion imposes the presence of axionless n-nbar mixing effects, either in vacuum or in decays, which are sufficiently constrained experimentally to leave no room for axion-induced oscillations. Thus, a generic scalar or axion-like dark matter background would have to exist to induce resonant n-nbar oscillations. Yet, if Nature has taken that path to relate dark matter and baryon number violation, the experimental signature would be striking and certainly worth pursuing.

    hep-phJHEP(2025)·4 citations
24. 24*

    Scalar resonance contributions in the $D_{s1}(2460{)}^{+}\to D_s^{+}{\pi }^{+}{\pi }^{-}$ reaction

    Zhong-Yu Wang🇨🇳 · Yu-Shuai Li🇨🇳 · Si-Qiang Luo🇨🇳

    Inspired by the newly observed $T_{c\bar{s}}$ state in the $D_{s1}(2460{)}^{+}\to D_s^{+}{\pi }^{+}{\pi }^{-}$ reaction by the LHCb Collaboration, we investigate the amplitude of this decay to explore the origins and properties of the open-charm tetraquark state based on the final state interaction. The invariant mass distributions of $D_s^{+}{\pi }^{+}$ and ${\pi }^{+}{\pi }^{-}$ are well reproduced by the $S$-wave scattering amplitudes of the coupled channel systems $D_s\pi$ and $\pi \pi$. However, neither the tree-level nor both the tree-level and $\pi \pi$ coupled channel scattering contributions can describe the experimental data well, which indicates that the $D_s\pi$ coupled channel scattering is required. We find that the $T_{c\bar{s}}$ and $f_0(500)$ resonances are dynamically generated from the pseudoscalar-pseudoscalar meson interaction within the chiral unitary approach. In addition, we find the corresponding poles and also calculate the $S$-wave scattering length for the $DK$ channel, which is on the same scale as the result extracted from the experiment. We propose that the $T_{c\bar{s}}$ and $f_0(500)$ resonances in the $D_{s1}(2460{)}^{+}\to D_s^{+}{\pi }^{+}{\pi }^{-}$ reaction are hadronic molecular type particles.

    hep-phPRD(2025)·10 citations
25. 25*

    Investigating the underlying structure of vector hidden-charm tetraquark states via their electromagnetic characteristics

    U. Özdem🇹🇷

    Accessing a full picture of the internal structure of hadrons would be a key topic of hadron physics, with the main motivation to study the strong interaction binding the visible matter. Furthermore, the underlying structure of known exotic states remains an unresolved fundamental issue in hadron physics, which is currently being addressed by hadron physics community. It is well known that electromagnetic characteristics can serve as a distinguishing feature for states whose internal structures are complex and not yet fully understood. The aim of this study is to determine the magnetic moments of vector hidden-charm tetraquark states by making use of QCD light-cone sum rules. In order to achieve this objective, the states mentioned above are considered in terms of the diquark-antidiquark structure. Subsequently, a comprehensive examination is conducted, with four distinct interpolating currents being given particular consideration, as these have the potential to couple with the aforementioned states. It has been observed that there are considerable discrepancies between the magnetic moment results extracted employing different diquark-antidiquark structures. Such a prediction may be interpreted as the possibility of more than one tetraquark with the identical quantum numbers and similar quark constituents, but with different magnetic moments. The numerical predictions yielded have led to the conclusion that the magnetic moments of the vector hidden-charm tetraquark states are capable of projecting the inner structure of these states, which may then be used to determine their quark-gluon structure and quantum numbers. In order to provide a comprehensive analysis, the individual quark contributions to the magnetic moments are also examined.

    hep-phhep-exhep-latPRD(2025)·9 citations
26. 26*

    Jet momentum reconstruction in the QGP background with machine learning

    Ran Li🇨🇳 · Yi-Lun Du🇨🇳 · Shanshan Cao🇨🇳

    We apply a Dense Neural Network (DNN) approach to reconstruct jet momentum within a quark-gluon plasma (QGP) background, using simulated data from PYTHIA and Linear Boltzmann Transport (LBT) Models for comparative analysis. We find that medium response particles from the LBT simulation, scattered out of the QGP background but belonging to medium-modified jets, lead to oversubtraction of the background if the DNN model is trained on vacuum jets from PYTHIA simulation. By training the DNN model on quenched jets generated using LBT or the combination of jet samples from PYTHIA and LBT, we significantly reduce this prediction bias and achieve more accurate background subtraction compared to conventional Area-based and Constituent Subtraction methods widely adopted in experimental measurements. We further study the performance of these machine learning models on evaluating the nuclear modification factor of jets, and find that while the unfolding procedure is necessary for correcting residuals in reconstructed jet momenta, models trained on samples incorporating quenched jets still achieve superior accuracy than those trained on vacuum jets even after unfolding.

    hep-phnucl-exnucl-thPLB(2025)·3 citations
27. 27*

    Verification of the tenth-Order QED contribution to the anomalous magnetic moment of the electron from diagrams without fermion loops

    Tatsumi Aoyama🇯🇵 · Masashi Hayakawa🇯🇵 · Akira Hirayama🇯🇵 · Makiko Nio🇯🇵

    A discrepancy of approximately 5$\sigma$ exists between the two known results for the tenth-order QED contribution to the anomalous magnetic moment of the electron, calculated from Feynman vertex diagrams without fermion loops. To investigate this, we decomposed this contribution into 389 parts based on a self-energy diagram representation, enabling a diagram-by-diagram numerical comparison of the two calculations. No significant discrepancies were found for individual diagrams. However, the numerical differences of the 98 diagrams sharing a common structure were not randomly distributed. The accumulation of these differences resulted in the 5$\sigma$ discrepancy. A recalculation with increased statistics in the Monte Carlo integration was performed for these 98 diagrams. By replacing the old values with the new ones for these 98 integrals, we have obtained a revised result of $6.800\pm 0.128$, thereby resolving the discrepancy.

    hep-phPRD(2025)·45 citations
28. 28*

    NLO QCD parton shower matching for $pp\to e^{+}{\nu }_e{\mu }^{-}{\bar{\nu }}_{\mu }\gamma +X$

    Ivan Rosario🇪🇸 · Francisco Campanario🇪🇸 · Simon Plätzer🇦🇹

    We present the implementation of a new interface in VBFNLO 3.0 supporting all di-boson and tri-boson processes with fully leptonic final states, enabling NLO+PS matched calculations. To demonstrate its capabilities, we study parton shower effects in the tri-boson production process $pp\to e^{+}{\nu }_e{\mu }^{-}{\bar{\nu }}_{\mu }\gamma +X$ using Herwig 7.3 with NLO QCD amplitudes from VBFNLO 3.0. We estimate uncertainties from scale variations and analyze the impact of generation-level cuts on parton shower events. This study showcases the new interface's potential and provides insights into the interplay between fixed-order calculations and parton shower effects in multi-boson production processes, crucial for precision measurements and BSM searches at the LHC and future colliders.

    hep-phhep-exPRD(2025)·1 citation
29. 29*

    Top observables as precise probes of the ALP

    Anh Vu Phan🇳🇱

    Measurements of the top quark by the ATLAS and CMS experiments go beyond testing the Standard Model (SM) with high precision. Axion-like particles (ALPs), a potential SM extension involving new pseudoscalar particles, exhibit strong interactions with heavy SM fermions. Consequently, they can significantly affect the kinematic distributions of top quarks in top-antitop pair production. Moreover, such strong interactions can induce other ALP couplings at low energies, leading to a rich phenomenology. We summarize recent developments in probing the ALP-top coupling and use LHC data from run 2 to constrain the ALP parameter space.

    hep-phhep-exSciPost Phys.Proc.(2026)·1 citation
30. 30*

    Transition form factors of the ${\Lambda }_b\to \Lambda (1520)$ in QCD light-cone sum rules

    Ke-Sheng Huang🇨🇳 · Hua-Yu Jiang🇨🇳 · Fu-Sheng Yu🇨🇳

    In this work, we investigate the transition form factors for ${\Lambda }_b\to \Lambda (1520)$ within the framework of light-cone sum rules (LCSR), using the light-cone distribution amplitudes (LCDAs) of the ${\Lambda }_b$-baryon. In the hadronic representation of the correlation function, we carefully select the appropriate Lorentz structures and isolate the contributions from both the $\Lambda (1520)(J^P=(3/2{)}^{-})$ and the $\Lambda (1890)(J^P=(3/2{)}^{+})$, ensuring that the form factors for ${\Lambda }_b\to \Lambda (1520)$ can be calculated unambiguously. We also provide predictions for various physical observables in the decay ${\Lambda }_b\to \Lambda (1520)l^{+}{l}^{-}$, including the differential branching fraction, the lepton-side forward-backward asymmetry, the longitudinal polarization fraction, and the CP-averaged normalized angular observable. Our prediction for the differential branching fraction of ${\Lambda }_b\to \Lambda (1520){\mu }^{+}{\mu }^{-}$ is in good agreement with the LHCb measurement within the uncertainties.

    hep-phEPJC(2025)·6 citations
31. 31*

    Full-colour double-virtual amplitudes for associated production of a Higgs boson with a bottom-quark pair at the LHC

    Simon Badger🇮🇹 · Heribertus Bayu Hartanto🇰🇷 · Rene Poncelet🇵🇱 · Zihao Wu🇨🇳 · Yang Zhang🇨🇳 · Simone Zoia🇨🇭

    We present the double-virtual amplitudes contributing to the production of a Higgs boson in association with a $b\bar{b}$ pair at the Large Hadron Collider. We perform the computation within the five-flavour scheme, which employs massless bottom quarks and finite bottom-Yukawa coupling, taking into account all the colour structures. We derive the analytic form of the helicity amplitudes through finite-field reconstruction techniques. The analytic expressions have been implemented in a public C++ library, and we demonstrate that evaluations are sufficiently stable and efficient for use in phenomenological studies.

    hep-phhep-thJHEP(2025)·27 citations
32. 32*

    On the determination of the relative probability of ${\rm Y}(5S)\to B_s^{(\ast )}{\bar{B}}_s^{(\ast )}$ decays

    A.E. Bondar🇷🇺 · E.K. Karkaryan🇷🇺 · A.A. Simovonian🇷🇺 · M.I. Vysotsky🇷🇺

    Semileptonic decays of the $B\overline{B}$ pairs produced in the ${\rm Y}(5S)$ can be used to find the relative probability of ${\rm Y}(5S)\to B_s{\overline{B}}_s$ decays. This could be achieved by the study of time dependence of $B$-meson decays to the leptons of equal and opposite signs.

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

    Challenges for Monte Carlo generators

    Jürgen Reuter🇩🇪

    This contribution lists challenges of Monte Carlo event generators for future lepton, especially linear colliders. A lot of the recent development benefits from the achievements at the Large Hadron Collider (LHC), but several aspects are unique for lepton colliders like beam simulation, polarization, electroweak higher order corrections and resummed QED corrections. We will describe the status of multi-purpose event generators and specialized codes and outline the challenges for these tools until such a collider starts data taking.

    hep-phhep-exEPJ Web Conf.(2024)·0 citations
34. 34*

    New developments in the Whizard event generator

    Jürgen Reuter🇩🇪 · Pia Bredt🇩🇪 · Marius Höfer🇩🇪 · Wolfgang Kilian🇩🇪 · Nils Kreher🇩🇪 · Maximilian Löschner🇩🇪 · Krzysztof Mękała🇩🇪 · Thorsten Ohl🇩🇪 · Tobias Striegl🇩🇪 · Aleksander Filip Żarnecki🇵🇱

    We give a status report on new developments within the Whizard event generator. Important new features comprise NLO electroweak automation (incl. extension to BSM processes like SMEFT), loop-induced processes and new developments in the UFO interface. We highlight work in progress and further plans, such as the implementation of electroweak PDFs, photon radiation, the exclusive top threshold and features for exotic new physics searches.

    hep-phhep-exEPJ Web Conf.(2024)·6 citations
35. 35*

    Event-by-event investigation of the kaon pair-source function with EPOS

    L. Kovacs🇭🇺 · D. Kincses🇭🇺 · M. Csanad🇭🇺

    In high-energy collisions, we can obtain information about the source function by measuring the two-particle Bose-Einstein correlation function and considering its relationship with the phase-space density of the particle-emitting source. While a Gaussian shape is commonly assumed, measurements and anomalous diffusion suggest Lévy-stable distributions, as observed in the PHENIX experiment for kaon-kaon pair-source functions. Event generators like EPOS allow direct investigation of freeze-out coordinates, facilitating the analysis of the source function. EPOS, a Monte Carlo-based model, simulates high-energy nuclear and particle collisions, integrating Parton-Based Gribov-Regge theory for initial evolution, subsequent hydrodynamic evolution, and hadronization. In this paper, we present an event-by-event analysis of the kaon source function in $\sqrt{s_{\text{NN}}}$ = 200 GeV Au+Au collisions using the EPOS model.

    hep-phPoS(2025)·2 citations
36. 36*

    Dark Matter Freeze-In during Warm Inflation and the Seesaw Mechanism

    Rayff de Souza🇧🇷 · Jamerson G. Rodrigues🇧🇷 · Clarissa Siqueira🇧🇷 · Felipe B. M. dos Santos🇧🇷 · Jailson Alcaniz🇧🇷

    A compelling way to address the inflationary period is via the warm inflation scenario, where the interaction of the inflaton field with other degrees of freedom affects its dynamics in such a way that slow-roll inflation is maintained by dissipative effects in a thermal bath. In this context, if a dark matter particle is coupled to the bath due to non-renormalizable interactions, the observed dark matter abundance may be produced during warm inflation via ultra-violet freeze-in. In this work, we propose applying this scenario in the framework of a $U(1{)}_{B-L}$ gauge extension of the Standard Model of Particle Physics, where we also employ the seesaw mechanism for generating neutrino masses.

    hep-phastro-ph.COhep-thJHEP(2025)·4 citations
37. 37*

    Three-loop jet function for boosted heavy quarks

    Alberto M. Clavero🇪🇸 · Robin Brüser🇩🇪 · Vicent Mateu🇪🇸 · Maximilian Stahlhofen🇩🇪

    We compute the inclusive jet function for boosted heavy quarks to $\mathcal{O}({\alpha }_s^3)$. The jet function is defined and calculated in the framework of boosted Heavy-Quark Effective Theory (bHQET). It describes the effect of radiation collimated in narrow jets arising from energetic heavy quarks on observables probing the jet invariant mass $M$ in the region where $M^2-m^2\ll m^2$, with $m$ the heavy quark mass. This kinematic situation is relevant e.g. in boosted top (pair) production at high-energy colliders. We have verified that our result satisfies non-Abelian exponentiation and checked that our calculation reproduces the known cusp and non-cusp anomalous dimensions of the jet function to $\mathcal{O}({\alpha }_s^3)$. We also confirmed that the $n_{\ell }^2{\alpha }_s^3$ contribution, where $n_{\ell }$ is the number of massless quark flavors, agrees with the prediction from renormalon calculus. Our computation provides the last missing piece to obtain the N${}^3$LL${}^{\prime }$ resummed (self-normalized) thrust distribution used for the calibration of the top quark mass parameter in parton-shower Monte Carlo generators. Our result also contributes to the invariant mass distribution of reconstructed top quarks at N${}^3$LL${}^{\prime }$, which can be employed for a precise top mass determination at future lepton colliders. As a by-product, we obtain the relation between the pole and short-distance jet-mass schemes at $\mathcal{O}({\alpha }_s^3)$. Finally, we estimate the non-logarithmic contribution to the four-loop jet function based on renormalon dominance.

    hep-phhep-thJHEP(2025)·6 citations
38. 38*

    Primordial Black Holes (as Dark Matter) from the Supercooled Phase Transitions with Radiative Symmetry Breaking

    Indra Kumar Banerjee🇮🇳 · Francesco Rescigno🇮🇹 · Alberto Salvio🇮🇹

    We study in detail the production of primordial black holes (PBHs), as well as their mass and initial spin, due to the phase transitions corresponding to radiative symmetry breaking (RSB) and featuring a large supercooling. The latter property allows us to use a model-independent approach. In this context, we demonstrate that the decay rate of the false vacuum grows exponentially with time to a high degree of accuracy, justifying a time dependence commonly assumed in the literature. Our study provides ready-to-use results for determining the abundance, mass and initial spin of PBHs generated in a generic RSB model with large supercooling. We find that PBHs are generically produced in a broad region of the model-independent parameter space. As an application, we identify the subregion that may explain recently reported microlensing anomalies. Additionally, we show that a simple Standard-Model extension, with right-handed neutrinos and gauged $B-L$ featuring RSB, may explain an anomaly of this sort in a region of its parameter space.

    hep-phastro-ph.COgr-qchep-thJCAP(2025)·25 citations
39. 39*

    Clear skies ahead: characterizing atmospheric gravity gradient noise for vertical atom interferometers

    John Carlton🇬🇧 · Valerie Gibson🇬🇧 · Tim Kovachy🇺🇸 · Christopher McCabe🇬🇧 · Jeremiah Mitchell🇬🇧

    Terrestrial long-baseline atom interferometer experiments are emerging as powerful tools for probing new fundamental physics, including searches for dark matter and gravitational waves. In the frequency range relevant to these signals, gravity gradient noise (GGN) poses a significant challenge. While previous studies for vertical instruments have focused on GGN induced by seismic waves, atmospheric fluctuations in pressure and temperature also lead to variations in local gravity. In this work, we advance the understanding of atmospheric GGN in vertical atom interferometers, formulating a robust characterization of its impact. We evaluate the effectiveness of underground placement of atom interferometers as a passive noise mitigation strategy. Additionally, we empirically derive global high- and low-noise models for atmospheric pressure GGN and estimate an analogous range for atmospheric temperature GGN. To highlight the variability of temperature-induced noise, we compare data from three prospective experimental sites. Our findings establish atmospheric GGN as comparable to seismic noise in its impact and underscore the importance of including these effects in site selection and active noise monitoring for future experiments.

    ↳ gr-qchep-phphysics.ao-phphysics.atom-ph+1PRD(2025)·10 citations
40. 40*

    The Status of Neutrino Cosmology: Standard $\Lambda$CDM, Extensions, and Tensions

    Helena García Escudero🇺🇸 · Kevork N. Abazajian🇺🇸

    We examine the performance of the six-parameter $\Lambda$CDM model and its extensions in light of recent cosmological observations, with particular focus on neutrino properties inferred from cosmology. Using a broad suite of nine combinations of datasets, with three separate analyses of the Planck Cosmic Microwave Background (CMB) data, and three separate supernovae (SNe) survey data, plus the recent DESI baryon acoustic oscillation (BAO) scale results, we derive constraints on the sum of neutrino masses ($\Sigma m_{\nu }$). Our results show upper limits in the range of $\Sigma m_{\nu }<76.9\mathrm{meV}$ to $\Sigma m_{\nu }<108\mathrm{meV}$ (95\% CL). The variation in the limits on $\Sigma m_{\nu }$ arises from the separate analyses of the Planck CMB data and the separate supernovae datasets, as they relate to the inferred matter density and its relation to the sensitivity of the BAO scale and CMB lensing to $\Sigma m_{\nu }$. In the context of hierarchical mass models in $\Lambda$CDM, we find a $1.47\sigma$ preference for normal ordering (NO) over inverted ordering (IO), with similar values of preference across all datasets. Despite the strong constraints, an inclination towards massless neutrinos over NO remains weak at $1.36\sigma$. We find that a ``negative'' neutrino mass, inferred from the shape of the likelihood in the physical regime, $\Sigma m_{\nu }>0$, is only present at less than $2\sigma$. We confirm that models allowing extra relativistic degrees of freedom, with $N_{\mathrm{eff}}\approx 3.5$, alleviate the Hubble tension. Significantly, we find a $3.3\sigma$ preference for a 0.1 eV partially thermalized sterile neutrino when the SH0ES $H_0$ measurement is included, a scale of interest in short-baseline oscillation experiment results. [abridged]

    ↳ astro-ph.COhep-phPRD(2025)·27 citations
41. 41*

    Perturbative stability of non-Abelian electric field solutions

    Jude Pereira🇺🇸 · Tanmay Vachaspati🇺🇸

    We consider SU(2) gauge theory with a scalar field in the fundamental representation. The model is known to contain electric field solutions sourced by the scalar field that are distinct from embedded Maxwell electric fields. We examine the perturbative stability of the solution and identify a region of parameter space where the solution is stable. In the regime where the scalar field has a negative mass squared, the solution has two branches and we identify an instability in one of the branches.

    ↳ hep-thhep-phPRD(2025)·1 citation
42. 42*

    Canonical formulation of the plasmon - hard particle scattering process in a quark-gluon plasma

    Yu.A. Markov · M.A. Markova

    It is shown that the Hamiltonian formalism proposed previously in [1] to describe the nonlinear dynamics of only {\it soft} fermionic and bosonic excitations contains much more information than initially assumed. In this paper, we have demonstrated in detail that it also proved to be very appropriate and powerful in describing a wide range of other physical phenomena, including the scattering of colorless plasmons off {\it hard} thermal (or external) color-charged particles moving in a hot quark-gluon plasma. A generalization of the Poisson superbracket including both anticommuting variables for hard modes and normal variables of the soft Bose field, is presented for the case of continuous medium. The corresponding Hamilton equations are defined, and the most general form of the third- and fourth-order interaction Hamiltonians is written out in terms of the normal boson field variables and hard momentum modes of the quark-gluon plasma. The canonical transformations involving both bosonic and hard mode degrees of freedom of the system under consideration, are discussed. The canonicity conditions for these transformations based on the Poisson superbracket, are derived. The most general structure of canonical transformations in the form of integro-power series up to sixth order in a new normal field variable and a new hard mode variable, is presented. For the hard momentum mode of quark-gluon plasma excitations, an ansatz separating the color and momentum degrees of freedom, is proposed. The question of approximation of the total effective scattering amplitude when the momenta of hard excitations are much larger than those of soft excitations of the plasma, is considered. The self-consistent system of Boltzmann-type kinetic equations taking into account the time evolution of the mean value of the color charge of the hard particle is obtained.

    ↳ hep-thhep-phInt.J.Mod.Phys.A(2026)·0 citations
43. 43*

    Data taking strategy for $\psi (3770)$ and ${\rm Y}(4S)$ branching fraction measurements at $e^{+}{e}^{-}$ colliders

    Jiaxin Li🇨🇳 · Xiantao Hou🇨🇳 · Junli Ma🇨🇳 · Changzheng Yuan🇨🇳 · Xiaolong Wang🇨🇳

    The $\psi (3770)$ and ${\rm Y}(4S)$ states predominantly decay into open-flavor meson pairs, whereas the decays of $\psi (3770)\to \text{mbox}\text{non}-D\bar{D}$ and ${\rm Y}(4S)\to \text{mbox}\text{non}-B\bar{B}$ are rare but crucial for elucidating the inner structure and decay dynamics of heavy quarkonium states. To achieve precise branching fraction measurements for $\psi (3770)\to \text{mbox}\text{non}-D\bar{D}$ and ${\rm Y}(4S)\to \text{mbox}\text{non}-B\bar{B}$ decays at the high luminosity $e^{+}{e}^{-}$ annihilation experiments, we employed Monte Carlo simulations and Fisher information to evaluate various data taking scenarios, ultimately determining the optimal scheme. The consistent results of both methodologies indicate that the optimal energy points for studies of $\psi (3770)\to \text{mbox}\text{non}-D\bar{D}$ decays are $3.769\text{gev}$ and $3.781\text{gev}$, whereas those for ${\rm Y}(4S)\to \text{mbox}\text{non}-B\bar{B}$ decays are $10.574\text{gev}$ and $10.585\text{gev}$. In addition, we studied the dependence of the precision in branching fraction measurements on the integrated luminosity, with the branching fractions spanning several orders of magnitude.

    ↳ hep-exhep-phCPC(2025)·0 citations
44. 44*

    Spin polarization of an expanding and rotating system

    Nora Weickgenannt🇫🇷 · Jean-Paul Blaizot🇫🇷

    We study the longitudinal spin polarization of a relativistic fluid of massive spin-1/2 particles undergoing a boost-invariant expansion in the longitudinal direction and rotating in the transverse plane. We express the polarization vector in terms of spin moments and derive closed equations of motion for the latter using spin kinetic theory with a nonlocal relaxation time approximation. These equations of motion are valid at any time of the evolution, from the free-streaming regime to the hydrodynamic regime. At late time, the polarization features contributions from gradients of the fluid velocity and of the temperature, that emerge from the nonlocal part of the collision term. Our results can be used to explore polarization phenomena in the context of heavy-ion collisions.

    ↳ nucl-thhep-phPRD(2025)·7 citations
45. 45*

    The UV Sensitivity of Axion Monodromy Inflation

    Enrico Pajer🇬🇧 · Dong-Gang Wang🇬🇧 · Bowei Zhang🇬🇧

    We revisit axion monodromy inflation in the context of UV-inspired models and point out that its cosmological observables are sensitive to heavy fields with masses far above the Hubble scale, such as the moduli of flux compactifications. By studying a string-inspired two-field extension of axion monodromy with a small turning rate, we reveal that the oscillatory modulation of the axion potential leads to continuous excitation of heavy fields during inflation when the modulation frequency exceeds the field masses. This finding challenges the conventional single-field description, heavy moduli cannot be simply integrated out. Using a full bootstrap analysis, we demonstrate that this mechanism produces cosmological collider signals that bypass the usual Boltzmann suppression for heavy masses. Specifically, we identify detectably large signatures of heavy moduli in the primordial bispectrum, offering a promising avenue for probing high-energy physics through cosmological observations.

    ↳ hep-thastro-ph.COgr-qchep-phSciPost Phys.(2026)·19 citations
46. 46*

    Testing for isospin symmetry breaking with extensive calculations of isotope shift factors in potassium

    Vaibhav Katyal🇮🇳 · A. Chakraborty🇮🇳 · B. K. Sahoo🇮🇳 · Ben Ohayon🇮🇱 · Chien-Yeah Seng🇺🇸 · Mikhail Gorchtein🇩🇪 · John Behr🇨🇦

    Precise evaluation of the isotope shift (IS) factors for seven low-lying potassium (K) states is achieved using relativistic coupled-cluster (RCC) theory. The energies of these states are assessed and compared with experimental data to confirm the accuracy of the wave functions calculated at varying RCC theory approximations and highlight the significance of many-body and relativistic effects in determining the energies and IS factors of K. Various methods are used to compute the IS factors, with the finite-field (FF) approach yielding results that align with observed and semi-empirical data. This consistency is attributed to orbital relaxation effects that are naturally present in the FF method but emerge only through complex interactions in other techniques. Using the IS factors derived from FF, we review the mean square radius difference between ${}^{38m}$K and ${}^{39}$K. From this difference and muonic atom x-ray spectroscopy, we deduce the absolute radius of ${}^{38m}$K using an updated calculation of the nuclear polarizability effect. Finally, we evaluate the isospin symmetry breaking (ISB) in this isotriplet by integrating the radius of ${}^{38m}$K with an updated radius of ${}^{38}$Ca, concluding that the ISB is compatible with zero. This finding offers a stringent benchmark for nuclear model calculations of ISB corrections in nuclear beta decay, which play a key role in determining the $V_{ud}$ matrix element.

    ↳ physics.atom-phhep-phnucl-exnucl-thPRA(2025)·13 citations
47. 47*

    Identifying weak critical fluctuations of intermittency in heavy-ion collisions with topological machine learning

    Rui Wang🇨🇳 · Chengrui Qiu🇨🇳 · Chuan-Shen Hu🇸🇬 · Zhiming Li🇨🇳 · Yuanfang Wu🇨🇳

    Large density fluctuations of conserved charges have been proposed as a promising signature for exploring the QCD critical point in heavy-ion collisions. These fluctuations are expected to exhibit a fractal or scale-invariant behavior, which can be probed by intermittency analysis. Recent high-energy experimental studies reveal that the signal of critical fluctuations related to intermittency is very weak and thus could be easily obscured by the overwhelming background particles in the data sample. Employing a point cloud neural network with topological machine learning, we can successfully classify weak signal events from background noise by the extracted distinct topological features, and accurately determine the intermittency index for weak signal event samples.

    ↳ nucl-thhep-phnucl-exPLB(2025)·6 citations
48. 48*

    Prompt searches for feebly interacting particles at the LHC

    Joscha Knolle for the ATLAS · CMS Collaborations

    Recent results from the ATLAS and CMS experiments in searches for prompt signatures of feebly interacting particles are presented. All presented results are based on the 2015-2018 data set of $13\mathrm{TeV}$ proton-proton collisions, corresponding to an integrated luminosity of about $140{\mathrm{fb}}^{-1}$. The discussed models include dark mesons, heavy neutral leptons, dark matter, and dark photons. The obtained exclusion limits significantly extend the probed parameter space and, in some cases, provide the first collider-based constraints for the considered models.

    ↳ hep-exhep-phPoS(2025)·0 citations
49. 49*

    Aspects of supersymmetry breaking driven inflation in orbifold models

    G. A. Diamandis🇬🇷 · K. Kaskavelis🇬🇷 · A. B. Lahanas🇬🇷 · G. Pavlopoulos🇬🇷

    We consider gravitationally induced corrections to inflaton potentials driven by supersymmetry breaking in a five-dimensional supergravity, compactified on a $S_1/Z_2$ orbifold. The supersymmetry breaking takes place on the hidden brane and is transmitted to the visible brane through finite one loop graphs giving rise to an inflaton potential which includes gravitationally induced terms. These corrections are significant for inflationary cosmology and have the potential to modify the predictions of widely studied supergravity models if the latter are embedded in this framework. To explore these effects we examine two classes of models those inspired by no-scale supergravity models and $\alpha$-attractors. Both models are compatible with current cosmological observations but face chalenges in reconciling enhanced values for the scalar power spectrum $P_{\zeta }$ with cosmological data, particularly regarding the tensor to scalar ratio $r$. In fact $P_{\zeta }\gtrsim 10^{-2}$ results to $r>\mathcal{O}(0.1)$, outside the limits put by current data.

    ↳ hep-thastro-ph.COgr-qchep-phEPJC(2025)·1 citation
50. 50*

    Revise the Dark Matter-Phantom Scalar Field Interaction

    Andronikos Paliathanasis🇿🇦 · Amlan Halder🇮🇳 · Genly Leon🇨🇱

    The cosmological history and evolution are examined for gravitational models with interaction in the dark sector of the universe. In particular, we consider the dark energy to be described by a phantom scalar field and the dark matter ${\rho }_m$ as a pressureless ideal gas. We introduce the interacting function $Q=\beta \left(t\right){\rho }_m$, where the function is considered to be proportional to $\dot{\varphi },{\dot{\varphi }}^2{H}^{-1},H$, or a constant parameter with dimensions of $\left[H_0\right]$. For the four interacting models, we study in details the phase space by calculating the stationary points. The latter are applied to reconstruct the cosmological evolution. Compactified variables are essential to understand the complete picture of the phase space and to conclude about the cosmological viability of these interacting models. The detailed analysis is performed for the exponential potential $V\left(\varphi \right)=V_0{e}^{\lambda \varphi }$. The effects of other scalar field potential functions on the cosmological dynamics are examined.

    ↳ gr-qcastro-ph.COhep-phPhys.Scripta(2025)·13 citations
51. 51*

    Prediction of an $I(J^P)=0(1^{-})$ $\bar{b}\bar{b}ud$ Tetraquark Resonance Close to the $B^{\ast }{B}^{\ast }$ Threshold Using Lattice QCD Potentials

    Jakob Hoffmann🇩🇪 · Marc Wagner🇩🇪

    We use antistatic-antistatic potentials computed with lattice QCD and a coupled-channel Born-Oppenheimer approach to explore the existence of a $\bar{b}\bar{b}ud$ tetraquark resonance with quantum numbers $I(J^P)=0(1^{-})$. A pole in the $\text{mbox}T$ matrix signals a resonance with mass $m=2m_B+94.0_{-5.4}^{+1.3}\text{MeV}$ and decay width $\Gamma =140_{-66}^{+86}\text{MeV}$, i.e. very close to the $B^{\ast }{B}^{\ast }$ threshold. We also compute branching ratios, which clearly indicate that this resonance is mainly composed of a $B^{\ast }{B}^{\ast }$ meson pair with a significantly smaller $BB$ contribution. By varying the potential matrix responsible for the coupling of the $BB$ and the $B^{\ast }{B}^{\ast }$ channel as well as the $b$ quark mass, we provide additional insights and understanding concerning the formation and existence of the resonance. We also comment on the importance of our findings and the main takeaways for a possible future full lattice QCD investigation of this $I(J^P)=0(1^{-})$ $\bar{b}\bar{b}ud$ tetraquark resonance.

    ↳ hep-lathep-phPRD(2025)·8 citations
52. 52*

    New leading contributions to non-gaussianity in single field inflation

    Ignatios Antoniadis🇹🇭 · Auttakit Chatrabhuti🇹🇭 · Jules Cunat🇫🇷 · Hiroshi Isono🇹🇭

    We compute the bispectrum of primordial density perturbations in CMB to second order in the slow-roll parameters of single field inflation. We correct previous results and found that next-to-leading order corrections can be of the same order as the leading order result in a large class of models, including hilltop inflation.

    ↳ hep-thastro-ph.COgr-qchep-phEPJC(2026)·4 citations
53. 53*

    How Well Do We Know the Scalar-Induced Gravitational Waves?

    A. J. Iovino🇮🇹 · S. Matarrese🇮🇹 · G. Perna🇨🇭 · A. Ricciardone🇮🇹 · A. Riotto🇨🇭

    Gravitational waves sourced by amplified scalar perturbations are a common prediction across a wide range of cosmological models. These scalar curvature fluctuations are inherently nonlinear and typically non-Gaussian. We argue that the effects of non-Gaussianity may not always be adequately captured by an expansion around a Gaussian field, expressed through nonlinear parameters such as $f_{\mathrm{NL}}$. As a consequence, the resulting amplitude of the stochastic gravitational wave background may differ significantly from predictions based on the standard quadratic source model routinely used in the literature.

    ↳ astro-ph.COgr-qchep-phPLB(2026)·30 citations
54. 54*

    Seesaw relation between the cosmological constant and the Higgs mass

    R.J. Cossins

    We propose the relation $M_{Higgs}^{\ast }=(M_{\Lambda }{M}_I{)}^{\frac{1}{2}}$ where $M_{Higgs}^{\ast },M_{\Lambda }$ and $M_I$ denote the mass scale associated with the Higgs boson, the cosmological constant and the inflaton respectively. We demonstrate how this seesaw-like (geometric mean) relation perfectly matches observations and the unified scenario of holographic constant roll inflation

    ↳ gr-qchep-ph0 citations
55. 55*

    Revisiting holographic dark energy from the perspective of multi-messenger gravitational wave astronomy: future joint observations with short gamma-ray bursts

    Tao Han🇺🇸 · Ze Li🇺🇸 · Jing-Fei Zhang🇺🇸 · Xin Zhang🇺🇸

    The advent of third-generation (3G) gravitational-wave (GW) detectors opens new opportunities for multi-messenger observations of binary neutron star merger events, holding significant potential for probing the history of cosmic expansion. In this paper, we investigate the holographic dark energy (HDE) model by using the future GW standard siren data observed from the 3G GW detectors and the short $\gamma$-ray burst THESEUS-like detector joint observations. We find that GW data alone can achieve a relatively precise estimation of the Hubble constant, with precision of $0.2\%$-$0.6\%$, but its ability to constrain other cosmological parameters remains limited. Nonetheless, since the GW data can break parameter degeneracies generated by the mainstream EM observations, CMB + BAO + SN (CBS), GW standard sirens play a crucial role in enhancing the accuracy of parameter estimation. With the addition of GW data to CBS, the constraints on cosmological parameters $H_0$, $c$ and ${\Omega }_{\mathrm{m}}$ can be improved by $63\%$-$88\%$, $27\%$-$44\%$ and $55\%$-$70\%$. In summary, observations of GW standard sirens from 3G GW detectors could be pivotal in helping solve the Hubble tension and probe the fundamental nature of dark energy.

    ↳ astro-ph.COastro-ph.HEgr-qchep-phUniverse(2025)·15 citations
56. 56*

    Dark Astronomy with Dark Matter Detectors

    Gonzalo Alonso-Álvarez🇨🇦 · David Curtin🇨🇦

    We present a novel way of probing non-gravitational dark matter interactions: dark astronomy, which leverages the dark radiation emitted by dissipative dark sectors. If the mediator of the dark matter self interactions is a dark photon with a small mass that kinetically mixes with the visible photon, the dark radiation flux becomes accessible to underground experiments. We argue that the emission may be dominantly longitudinally polarized, thereby enhancing the sensitivity of direct detection experiments such as XENON and SENSEI to this signal. We introduce a new detection mechanism based on resonant dark-photon-to-photon conversion at the surface of conducting materials, which offers unique directional sensitivity to dark radiation. This mechanism facilitates the development of experiments that combine dark matter detection techniques with methods of traditional astronomy, opening the possibility to map dark radiation sources within our galaxy.

    ↳ astro-ph.COhep-phJCAP(2025)·2 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.