Fri·Aug 8, 2025Friday·August 8, 2025

1. 01*

   Detecting the $\pi$-axiverse through parametric resonance

   Stephon Alexander🇺🇸 · Geoff Beck🇿🇦 · Santiago Loane🇺🇸 · Tucker Manton🇺🇸

   Axions are a leading dark matter candidate. In this work, we study the detectability of a multi-axion-like model, dubbed the $\pi$-axiverse, that is distinguishable from the string axiverse. The dark matter candidates are $N^2-1$ pseudo-Nambu-Goto modes (pion- and kaon-like states) stemming from spontaneous breaking of a global $SU(N)$ flavor symmetry. The low energy theory includes $N-1$ axionic couplings with additional couplings to the Standard Model photon kinetic energy, reminiscent of the string theory dilaton-photon coupling. We explore the parametric resonance of photons interacting with such a dark sector. Axions are well known to form macroscopic solitonic-like objects (axion stars), which experience instabilities due to overdensities stemming from mergers or accretion processes. The instabilities produce high-intensity bursts of radiation via parametric resonance that may be detected at observatories such as MeerKAT, the Square Kilometre Array (SKA), and the next generation Very Large Array (ngVLA). Using numerical methods, we systematically explore the multi-dimensional parameter space of the $\pi$-axiverse to search for regions where such signals are detectable, which generically differ from single axion models. We identify regions of the parameter space where MeerKAT, SKA, and ngVLA can resolve such signals, assessing the potential of transient searches to constrain the model. Our results provide a significant step forward in understanding the phenomenology and indirect detection of multi-axion-dilaton dark matter.

   hep-ph4 citations
2. 02*

   Minicharged Particle Sensitivity of the MAPP Outrigger Detector

   Matti Kalliokoski🇫🇮 · Vasiliki A. Mitsou🇪🇸 · Marc de Montigny🇨🇦 · Abhinab Mukhopadhyay🇨🇦 · Pierre-Philippe A. Ouimet🇨🇦 · James Pinfold🇨🇦 · Ameir Shaa🇨🇦 · Michael Staelens🇪🇸

   We present a detailed study of the projected background-free sensitivity of the MAPP Outrigger Detector (OD) to minicharged particles (mCPs) at the High-Luminosity Large Hadron Collider (HL-LHC). As the first upgrade to the MAPP Experiment, the MAPP OD is a standalone detector designed to offer enhanced sensitivity to high-mass mCPs with intermediate effective charges. The MAPP OD is planned for installation in a duct adjacent to the MAPP-1 detector, located between the LHC's UA83 gallery and the beamline. Considering mCP production via the Drell-Yan mechanism and various meson decays, the results show that, at the 95% confidence level, the MAPP OD can extend the experiment's upper mass reach to mCP masses of approximately 200 GeV at the HL-LHC.

   hep-phhep-ex2 citations
3. 03*

   Quark confinement in presence of both chromoelectric and chromomagnetic fields and the structure of spacetime

   Abdellah Touati · Soufiane Boukhalfa

   The strong interaction between quarks inside hadrons in curved spacetime is investigated in the presence of a new non-abelian gauge potential based on the $SU(3)$ group. This potential presented both chromo-electric and chromo-magnetic fields, including a magnetic monopole-like term, together with a radial non-Abelian Coulomb-like component. A spacetime metric induced by the presence of a Yang-Mills field is derived by solving Einstein's equations in the specific limit where the $SU(3)$ gauge symmetry is reduced to an embedded $SU(2)$ subgroup, accompanied by a dynamical $U(1)$ monopole sector. It is explicitly shown that the Schwarzschild radius of the strong interaction between quarks within hadrons corresponds approximately to the size of these latter and that the corresponding, for both quarks and gluons, wave function presents a discontinuity at Schwarzschild surface. The obtained results allow us to interpret the confinement of quarks as a geometric property of spacetime, emerging naturally from its structure without introducing any confinement potential. Moreover, the energy spectra of quarks in presence of chromo-electric and chromo-magnetic fields reproduce the mass of hadrons with a very good accuracy compared to the experimental data, and the presence of the residual non-abelian term correction enhance our numerical results.

   hep-phhep-th0 citations
4. 04*

   Gravitational Waves from Dark Gauge Sectors

   Alexander Belyaev🇬🇧 · Mårten Bertenstam🇸🇪 · João Gonçalves🇵🇹 · António P. Morais🇵🇹 · Roman Pasechnik🇸🇪 · Nakorn Thongyoi🇹🇭

   We explore gravitational-wave (GW) signatures from a strong first-order phase transition in a non-Abelian dark sector, which naturally gives rise to vector dark matter (DM). We consider a general class of models featuring a new dark gauge sector communicating with the Standard Model (SM) through a Higgs portal and a vector-like fermionic portal. We also study the scenario where the dark sector interacts with the SM only via gravity. In all cases, we scan the full parameter space and analyse GW production and highlight the regions with visible GW signatures. Notably, the fermionic portal yields distinctive GW signals at LISA with peak frequencies of 1--10 mHz, reaching up to 1 Hz for future interferometers like BBO and DECIGO, while the Higgs portal scenario remains limited to around 1 mHz. Both frameworks account for the observed DM abundance and predict detectable LISA signals for dark vector bosons near 1--4 TeV, with a $\sim$10 GeV dark Higgs. Finally, we identify a unique six-top final state from pair-produced vector-like fermions, offering a striking collider signature within HL-LHC reach. Its detection would provide a smoking-gun signal for the fermionic portal, establishing complementarity between collider, GW, and DM signals.

   hep-phJHEP(2026)·3 citations
5. 05*

   Rediscovering the Standard Model with AI

   Aya Abdelhaq🇺🇸 · Pellegrino Piantadosi🇦🇪 · Fernando Quevedo🇬🇧

   We investigate whether artificial intelligence can autonomously recover known structures of the Standard Model of particle physics using only experimental data and without theoretical inputs. By applying unsupervised machine learning techniques -- including data dimensionality reduction and clustering algorithms -- to intrinsic particle properties and decay modes, we uncover key organizational features of particle physics, such as the relative strength of different interactions and the difference between baryons and mesons. We also identify conserved quantities such as baryon number, strangeness and charm as well as the structure of isospin and the Eightfold Way multiplets. Our analysis then reveals that clustering can separate particles by interaction, flavor symmetries as well as quantum numbers. Additionally, we observe patterns consistent with Regge trajectories in baryon excitations. Our results demonstrate that machine learning can reproduce key aspects of the Standard Model directly from data, suggesting a promising path toward data-driven discovery in fundamental physics.

   hep-phhep-thphysics.data-anJHEP(2026)·2 citations
6. 06*

   Anisotropic modifications to the transport phenomena and observables in a hot QCD medium at finite baryon asymmetry

   Shubhalaxmi Rath🇨🇱

   We have studied how the transport of charge and heat as well as associated observables become influenced by a weak-momentum anisotropy arising due to the asymptotic expansion of baryon asymmetric matter in the initial stages of heavy ion collisions. This study facilitates the understanding of the local equilibrium property of the medium through the Knudsen number, and explores the correlation between the heat flow and the charge flow through the Lorenz number in the Wiedemann-Franz law for an anisotropic hot QCD medium at finite baryon asymmetry. We have determined the electrical and the thermal conductivities by solving the relativistic Boltzmann transport equation in the relaxation time approximation within the kinetic theory approach. The interactions among partons are appended through their distribution functions within the quasiparticle model of the hot QCD medium at finite temperature, anisotropy and baryon asymmetry. We have observed a decrease in both electrical and thermal conductivities in the presence of expansion-induced anisotropy for baryonless scenario as well as for baryon asymmetric scenario. Conversely, these conductivities are found to be larger in the baryon asymmetric matter as compared to their counterparts in the baryonless matter. The impact of anisotropy on the baryon asymmetric matter is as conspicuous as on the baryonless matter. The above results are attributed to the squeezing of the distribution function due to the momentum anisotropy generated by the asymptotic expansion of baryon asymmetric matter and the dispersion relations of partons in the presence of anisotropy. Additionally, the aforesaid observables are also modulated by the expansion-induced anisotropy in the baryon asymmetric medium, indicating new predictions for the equilibrium characteristic and the relative behavior between the heat and charge flow for the said medium.

   hep-phhep-thnucl-thEPJA(2026)·3 citations
7. 07*

   Hadronic decay $D^{+}\to {\pi }^{+}\eta \eta$ and the $a_0(980)$ and $f_0(1370)$ contributions

   Wen-Tao Lyu🇨🇳 · Le-Le Wei🇨🇳 · De-Min Li🇨🇳 · En Wang🇨🇳

   Motivated by the resent BESIII Collaboration measurements of the process $D^{+}\to {\pi }^{+}\eta \eta$, we investigate this process by considering the contribution from the resonance $a_0(980)$, which is generated by $S$-wave pseudoscalar meson-pseudoscalar meson interaction, and the contribution from the intermediate scalar meson $f_0(1370)$. Our results could give a good description of the ${\pi }^{+}\eta$ and $\eta \eta$ invariant mass distributions, which implies that the contribution from the intermediate $f_0(1370)$, neglected in BESIII analysis, could play a role in this process. Furthermore, the predicted Dalitz plots are also consistent with the BESIII measurements. The more precise measurements about this process in future could shed light on the mechanism of this process and the properties of $f_0(1370)$ and $a_0(980)$.

   hep-phPRD(2025)·6 citations
8. 08*

   Constraints on Symmetric Dark Matter from Neutron Star Capture and Collapse

   Yuxin Liu🇨🇳 · Zhen Liu🇺🇸 · Maxim Pospelov🇺🇸 · Sanjay Reddy🇺🇸

   Dark matter (DM) models with a conserved particle$-$antiparticle number, $n_{\chi }-n_{\tilde{\chi }}$, and the asymmetry in the cosmological abundance $n_{\chi }\ne n_{\tilde{\chi }}$, are known to be challenged by the existence of old neutron stars (NSs), as the sufficient accumulation of DM will lead to the collapse of NSs into black holes. We demonstrate that the applicability of these constraints is much wider and covers models with symmetric populations of DM, $n_{\chi }=n_{\tilde{\chi }}$, as the process of DM capture regulated by a nucleon-DM scattering can be inherently asymmetric, ${\sigma }_{\chi n}\ne {\sigma }_{\tilde{\chi }n}$. The asymmetry is induced by the interference of different types of $\chi$-$n$ interactions, provided that their combination is odd under charge conjugation in the DM sector, $C_{\chi }$, and even under combined parity $P_{\chi +n}$. We provide a complete analysis of DM-nucleon bilinear $\chi$-$n$ interactions and find that this asymmetry is very generic. Using canonical NS parameters and local DM halo inputs, we exclude spin-averaged scattering cross sections down to ${\sigma }_{n\chi }\gtrsim 10^{-46}{\mathrm{cm}}^2$ at DM mass $m_{\chi }\lesssim 10^{10}\mathrm{GeV}$ for the maximally asymmetric capture rate, and show that the constraints persist down to very small values of the cross-section asymmetry, $\mathcal{A}=({\sigma }_{\chi n}-{\sigma }_{\tilde{\chi }n})/({\sigma }_{\chi n}+{\sigma }_{\tilde{\chi }n})\gtrsim 10^{-5}$.

   hep-phastro-ph.HEPRL(2026)·7 citations
9. 09*

   Type-III Seesaw in Non-Holomorphic Modular Symmetry and Leptogenesis

   Priya🇮🇳 · Labh Singh🇮🇳 · B. C. Chauhan🇮🇳 · Surender Verma🇮🇳

   Recently, Qu and Ding, have proposed a formalism where modular invariance is extended to non-supersymmetric scenario considering Yukawa couplings as non-holomorphic functions of modules field $\tau$. Adopting this formalism in this work, we propose a Type-III seesaw model as a unified framework to explain lepton masses and mixing and baryogenesis via leptogenesis. ${\chi }^2$ analysis is performed to fit the neutrino oscillation data from NuFIT~6.0 leading to a normal hierarchical pattern of neutrino masses and constrained $CP$ phases. Furthermore, we analyze the generation of the observed baryon asymmetry of the Universe via thermal leptogenesis where the decays of the lightest fermion triplet ${\Sigma }_1$ into lepton-Higgs final states produce a $CP$ asymmetry ${\epsilon }_{CP}$. The complex modules $\tau$ is responsible for the $CP$ asymmetry produced during leptogenesis. The washout processes dominated by gauge scatterings and inverse decays are studied through the full set of Boltzmann equations. The resulting $B-L$ asymmetry, $Y_{B-L}\sim 10^{-9}$ successfully reproduces the baryon-to-photon ratio demonstrating the model's capability to link low-energy neutrino data with the baryogenesis. The strong gauge-mediated washout of fermion triplets necessitates a leptogenesis scale of $\mathcal{O}(10^{12}\mathrm{GeV})$ ensuring compatibility with both the Davidson-Ibarra bound and the thermal history of the Universe. Future pursuits remain open to the exploration of novel avenues aimed at lowering the energy scale associated with leptogenesis.

   hep-phhep-thJHEP(2026)·16 citations
10. 10*

    The sixth order QED radiative corrections to lepton anomalies due to the fourth order vacuum polarization insertions within the Mellin-Barnes representation

    L.P. Kaptari🇷🇺 · V.I. Lashkevich🇧🇾 · O.P. Solovtsova🇷🇺

    The explicit form of the sixth order radiative corrections to the lepton $L$ ($L=e,\mu$ and $\tau$) anomalous magnetic moment from QED Feynman diagrams with insertion of the fourth-order polarization operators consisting of either two closed lepton loops or one lepton loop crossed by a photon line is discussed in detail. The approach is based on the consistent application of dispersion relations for vacuum polarization operators and the Mellin-Barnes transform for massive photon propagators. Explicit analytical expressions for corrections to the lepton anomaly are obtained for the first time in the whole interval $0<r<\infty$ of the ratio $r$ of lepton masses $m_{\ell }/m_L$. Asymptotic expansions in the limit of both small $r\ll 1$ and large $r\gg 1$ computed from the exact expressions are found to be in perfect agreement with the ones earlier reported in the literature. We argue that in the region wherethe physical lepton mass ratios are located, the asymptotic expansions hold with an accuracy higher than the experimentally measured anomalies. The two loop diagrams with all three leptons different from each other are computed numerically and compared with the corresponding corrections from the pure two-bubble and one-bubble mixed diagrams. It is shown that there are regions of ratios $r$ where all three types of the fourth order polarization operator contribute equally to the anomaly.

    hep-phhep-thPRD(2025)·0 citations
11. 11*

    Probing lepton flavor violating dark matter scenarios via astrophysical photons and positrons

    Jin-Han Liang🇨🇳 · Yi Liao🇨🇳 · Xiao-Dong Ma🇨🇳

    In this Letter we explore, for the first time, the constraints on lepton flavor violating (LFV) dark matter (DM) scenarios via the astrophysical photons and positrons, including both the annihilation and decay modes, $\mathtt{DM}(+\mathtt{DM})\to e^{\pm }{\mu }^{\mp },e^{\pm }{\tau }^{\mp },{\mu }^{\pm }{\tau }^{\mp }$. Given the presence of LFV interactions in various DM models and the challenge of probing such interactions at terrestrial facilities, such as DM direct detection and collider experiments, indirect detection offers a unique approach to investigating them. We utilize the currently available photon datasets from the XMM-Newton, INTEGRAL, and Fermi-LAT telescopes, along with the positron datasets from the AMS-02 satellite, to establish stringent bounds on the relevant annihilation cross sections or decay widths. In particular, we include contributions to the photon spectrum from final state radiation, radiative decays, and inverse Compton scattering. We find that the INTEGRAL (AMS-02) provides the most stringent bound on the annihilation cross sections and decay widths for DM mass below (above) approximately 20 GeV, which are comparable to those of their lepton flavor conserving counterparts.

    hep-phPRD(2026)·2 citations
12. 12*

    An analysis of nuclear parton distribution function based on relative entropy

    Shu-Man Hu🇨🇳 · Ao-Sheng Xiong🇨🇳 · Ji Xu🇨🇳 · Fu-Sheng Yu🇨🇳 · Ji-Xin Yu🇨🇳

    In this work, we propose a method to quantify the difference between nuclear parton distribution functions in different nuclei and parton distribution functions in free nucleons using the relative entropy (also known as Kullback-Leibler divergence), a measure widely employed in quantum information theory. By introducing certain constraints and the ``minimum relative entropy" hypothesis, we can determine the shape of the structure function in the intermediate-$x$ region, which is intimately connected with the renowned EMC effect. For quark structure functions, our results align with the latest global fits to experimental data. This agreement suggests that the relative entropy-based methodology may provide novel insight into the structure of nucleons, particularly in cases where experimental data and theoretical QCD constraints are limited, such as those pertinent to gluon nPDFs. Therefore, we applied this methodology to gluon nPDFs, analyzing the results from two commonly used global fitting groups, EPPS21 and nNNPDF3.0. Our analysis suggests that the central values of EPPS21 align more closely with the ``minimum relative entropy" hypothesis. This finding underscores the utility of the proposed method and provides a valuable reference for future global fitting of nPDFs.

    hep-phCPC(2026)·2 citations
13. 13*

    Bottom baryon decays into light meson and dark baryon within perturbative QCD approach

    Ye Xing🇨🇳 · Yu-Ji Shi🇨🇳 · Xiao-Hui Hu🇨🇳

    In the work, we study the production of dark baryon $\psi$ with the bottom-baryon decays ${\Lambda }_b\to M\psi$ under the perturbative QCD approach. For the Type-I/II models in B-Mesogenesis scenarios, we calculate the form factors for bottom-baryon decays into meson. Using these results, we obtain branching ratios for ${\Lambda }_b\to M\psi$ decays. The PQCD approach calculations show these branching ratios reach $\mathcal{O}(10^{-5})$ in both models, with $\mathcal{B}({\Lambda }_b\to K\psi )$ specifically reaching $\mathcal{O}(10^{-4})$ in Type-II. These accessible magnitudes make the predictions testable at the LHCb and B-factories with improved precision.

    hep-phPRD(2025)·4 citations
14. 14*

    An analysis of the fragmentation function of gluon at next-to-leading order approximation

    H.S.Nakhaei🇮🇷 · G.R.Boroun🇮🇷

    We are investigating the behavior of the fragmentation function of a gluon, denoted as $D_g(x,{\mu }^2)$, where $\mu$ represents the observable scale. This function is derived from the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equations. Our objective is to evolve the fragmentation function of a gluon for heavy-quark-antiquark bound states with large transverse momentum using a Laplace transform technique. This method enables us to calculate numerical solutions for two and four quarkonium states based on the known initial fragmentation function of gluons. We examine both leading-order (LO) and higher-order approximations for the fragmentation function of a gluon, $[g\to T_{nQ}]$, by integrating the evolved fragmentation function of the gluon at the initial scale. In our computations, we utilize the initial scales for $T_g^{2c}$ from Braaten-Yuan [E.Braaten and T.C.Yuan, Phys. Rev. Lett. {\bf71}, 1673 (1993)] and for $T_g^{4c}$ and $T_g^{4b}$ from Celiberto-Gatto-papa [ F. G. Celiberto, G. Gatto and A. Papa, Eur. Phys. J. C {\bf84}, 1071 (2024)] and Celiberto-Gatto [ F. G. Celiberto and G. Gatto, Phys. Rev. D {\bf111}, 034037 (2025)] respectively. Through comparing our predictions with existing literature results, we can accurately determine the evolution of the fragmentation function of a gluon at scale $\mu$.

    hep-phPRD(2025)·5 citations
15. 15*

    Pseudorapidity dependence of charged particles production in non-single diffractive $pp$ collisions in the PACIAE 4.0 model

    Z. Xie🇨🇳 · A.K. Lei🇨🇳 · H. Zheng🇨🇳 · W.C. Zhang🇨🇳 · D.M. Zhou🇨🇳 · Z.L. She🇨🇳 · Y.L. Yan🇨🇳 · B.H. Sa🇨🇳

    Studying experimental observables is a key benchmark for validating theoretical models in high energy physics. In this work, we employ the PACIAE 4.0 model to simulate non-single diffractive proton-proton ($pp$) collisions at center-of-mass energies of 0.9, 2.36, and 7 TeV, comparing the results with Compact Muon Solenoid (CMS) experimental data on charged-particle pseudorapidity densities and transverse momentum spectra across different pseudorapidity bins, respectively. Our results show good agreement with the CMS data, particularly only using a single set of parameters for all collision energies. This demonstrates that the PACIAE 4.0 model can serve as a reliable tool for systematically studying the physics of NSD $pp$ collisions.

    hep-phPRC(2026)·1 citation
16. 16*

    An examination of the two-peak hypothesis of $P_{\Psi s}^{\Lambda }(4459)$ using heavy quark symmetries

    Duygu Yıldırım🇹🇷

    The LHCb Collaboration announcement regarding the observation of the $P_{\Psi s}^{\Lambda }(4459)$ stated that it might consist of two resonances rather than a single one. Naturally, the structure and composition of $P_{\Psi s}^{\Lambda }(4459)$ state has prompted significant interest among researchers. Within the framework of generalized flavor-spin symmetry, the $P_{\Psi s}^{\Lambda }(4459)$ has been correlated with the previously identified as one-peak states $P_c(4450)$, which were later found to be two-peak, $P_{c\bar{c}}(4440)$ and $P_{c\bar{c}}(4457)$. We investigate whether the $P_{\Psi s}^{\Lambda }(4459)$ embodies one or two distinct resonances. Notably, one of the predicted peaks posited by LHCb analysis appears to correspond to a ${\bar{D}}^{\ast }{\Xi }_c$ molecular state.

    hep-phNPA(2025)·0 citations
17. 17*

    On the origin of the $N{c}^1$ scaling in the confined but chirally symmetric phase at high T

    L. Ya. Glozman🇦🇹

    There is lattice evidence that the QCD matter above the chiral restoration temperature Tch and below the deconfinement temperature Td, called stringy fluid, is characterized by an approximate chiral spin symmetry, which is a symmetry of confinement in QCD with light quarks. The energy density, pressure and entropy density in the stringy fluid scale as Nc^1, which is in contrast to the Nc^0 scaling in the hadron gas and to the Nc^2 scaling in the quark-gluon plasma. Here we clarify the origin of the Nc^1 scaling. We employ a solvable field-theoretical large $N_c$ chirally symmetric and confining model. In vacuum the confining potential induces a spontaneous breaking of chiral symmetry. The mesons are spatially localized states of quarks and antiquarks. Still in the confining regime the system undergoes the chiral restoration phase transition at $T_{ch}$ because of Paili blocking of the quark levels required for the existence of the quark condensate, by the thermal excitation of quarks and antiquarks. The same Paili blocking leads to a delocalization of the color singlet low-spin meson-like states that become infinitely large in the chiral limit. Consequently the stringy fluid represents a very dense medium of the overlapping huge color-singlet low-spin quark-antiquark systems. The Bethe-Salpeter equation that determines the rest-frame excitation energies of the color-singlet quark-antiquark system is Nc-independent both in vacuum and in the medium in the confining regime. The excitation energy of the quark-antiquark color-singlet systems scales as Nc^0, i.e. as meson mass in vacuum. The Nc^1 scaling of the energy density in the stringy fluid is provided by the fluctuations of the color-singlet quark-antiquark systems.

    hep-phhep-lathep-thnucl-thEPJC(2025)·4 citations
18. 18*

    Comment on "Standard Model Mass Spectrum and Interactions In The Holomorphic Unified Field Theory"

    James M. Cline🇨🇦

    In arXiv:2508.02747 a theory that unifies gravity and the Standard Model was proposed. It is finite, unitary, and accurately predicts all parameters of the Standard Model in terms of only two input parameters. Here I point out one prediction that was overlooked, namely that the photon acquires a mass at one loop due to the lack of gauge invariance in the nonlocal interaction vertices of the proposed model. In a second iteration, a red herring concerning Wick rotation is clarified, and the difficulties relating to gauge invariance in the theory are further spelled out. I point out that their model apparently has a domain wall problem.

    hep-ph3 citations
19. 19*

    A short review of the vector charmonium-like state $\psi (4230)$

    Qian Wang🇨🇳 · Qiang Zhao🇨🇳

    We present a concise review of the vector charmonium state $\psi (4230)$, which was originally labelled as $Y(4260)$ in the literature. As one of the earliest candidates for a QCD exotic states, its interpretation has initiated various ideas about possible manifestations of non-perturbative mechanisms in the charmonium mass regime. In this short article we briefly review the experimental status of $\psi (4230)$ and discuss possible theoretical interpretations. We will focus on four broadly investigated scenarios, i.e. tetraquark, hybrid, hadro-quarkonium, and hadronic molecule, and highlight the key issues based on these approaches. Crucial experimental observables, e.g. mass position, lineshapes, di-lepton decay width ${\Gamma }_{ee}$, production rates in $B$ meson decays, dominant hadronic decay patterns, and the potential $1^{-+}$ and $0^{--}$ exotic partners, are assessed, which can provide crucial structure information for understanding this mysterious state.

    hep-phChin.Phys.Lett.(2025)·7 citations
20. 20*

    QCD condensates and ${\alpha }_s$ from $e^{+}{e}^{-}$ and $\tau$-decays

    Stephan Narison (LUPM-CNRS Montpellier-FR and iHEPMAD-Univ. Antananarivo-MG)🇫🇷

    In this talk, I review the determinations of the QCD condensates and ${\alpha }_s$ within the SVZ expansion using the ratio of Laplace sum rule (LSR) and $\tau$-like moments in $e^{+}{e}^{-}\to I=1$ Hadrons and in $\tau \to {\nu }_{\tau }+$Hadrons Axial-vector (A) and V-A channels. Some misprints in the original papers [1-3] have been corrected. We found that the value of the gluon condensate agrees with the one $⟨{\alpha }_s{G}^2⟩=(6.35\pm 0.35)\times 10^{-2}$ GeV${}^4$ from quarkonia and some other sum rules but less accurate, while the factorization of the four-quark condensate is violated by a factor about 6: $\rho ⟨\bar{\psi }\psi {⟩}^2=(5.98\pm 0.64)\times 10^{-4}$ GeV${}^6$ which confirms previous findings. Extracting the QCD condensates up to dimension D=20 from $e^{+}{e}^{-}$ and the axial-vector channel of $\tau$-decay, we do not find any exponential growth of their values in the Euclidian region, thus excluding (by duality) any significant effect of the so-called Duality Violation (DV) in the Time-like one. The optimal values of ${\alpha }_s(M_{\tau })$ from $e^{+}{e}^{-}\to$ Hadrons and $\tau$-decays agree each others and lead to the average: ${\alpha }_s(M_{\tau })=0.3128(51)$ [resp.0.3330(57)] $⟶{\alpha }_s(M_Z)=0.1176$ [resp. 0.1201] $(7{)}_{fit}(3{)}_{evol.}$ for Fixed Order (FO) [resp. Contour improved (CI)] PT series to be compared with the PDG24 average (without Lattice calculations): ${\alpha }_s(M_Z)=0.1175(10)$.

    hep-phhep-exhep-latJ.Subatomic Part.Cosmol.(2025)·1 citation
21. 21*

    Partially flavour non-universal $U(1)$ and radiative fermion masses

    Gurucharan Mohanta🇮🇳 · Ketan M. Patel🇮🇳

    We investigate an extension of the Standard Model with a partially flavour non-universal abelian gauge symmetry that enables radiative mass generation for lighter fermions. With flavour-universal charges for the first two generations, gauge-induced loop corrections generate second-generation masses while keeping the first generation massless. Small first-generation masses can arise from subdominant scalar loops within this framework. A single anomaly-free $U(1)$ is sufficient for a realistic model, and the partial universality relaxes the gauge boson mass bound from several thousand TeV to about 200 TeV compared with previous frameworks of this type. We also identify an alignment limit matching the lightest scalar to the observed Higgs and compute its couplings with the fermions, which largely agree with Standard Model values but show testable deviations.

    hep-phhep-thJHEP(2026)·3 citations
22. 22*

    Vertex corrections and wavefunction renormalization for atoms, nuclei, and other heavy composite particles

    Ryan Plestid🇺🇸 · Mark B. Wise🇺🇸

    We study QED corrections to operator matrix elements involving heavy composite particles (e.g., heavy-mesons, nuclei, and atoms). We define a new notion of reducible and irreducible graphs which is useful for systems with many discrete excited states. The equivalence of the LSZ reduction formula and old fashioned perturbation theory is explicitly demonstrated. The self energy and vertex corrections are defined (to all orders), and the one-loop corrections are reduced to operator matrix elements which may be evaluated by hadronic, nuclear, or atomic theorists. The gauge dependence of the various pieces are studied in detail at one loop, and cancellation of spurious contributions are demonstrated in a class of covariant gauges; Coulomb gauge is also discussed. The formalism is applied to superallowed beta decay where the one-loop structure is connected to existing literature based on current algebra techniques. We further identify the well known $O(Z^2{\alpha }^2)$ isospin breaking correction from the intranuclear Coulomb field as arising from two-loop diagrams. We comment on future applications of our results to the radiative corrections necessary in extractions of $|V_{ud}|$, in particular for corrections that required beyond one-loop order.

    hep-phhep-thnucl-thPRD(2026)·4 citations
23. 23*

    Factorization and resummation of QED radiative corrections for neutron beta decay

    Zehua Cao🇺🇸 · Richard J. Hill🇺🇸 · Ryan Plestid🇺🇸 · Peter Vander Griend🇺🇸

    Details of the two-loop analysis of long-distance QED radiative corrections to neutron beta decay are presented. Explicit expressions are given for hard, jet, and soft functions appearing in the factorization formula that describes the small mass/large energy limit. Power corrections, cancellation of singularities in the small mass expansion, renormalization scheme dependence, and bound state effects are discussed. The results impact the determination of $|V_{ud}|$ from the measured neutron lifetime.

    hep-phhep-exnucl-thPRD(2025)·9 citations
24. 24*

    Inclusion of the Longitudinal Momentum-Transfer Component and Kinematic Factors in a diffraction approach for H(d,p)X Reactions

    Ya. D. Krivenko-Emetov🇺🇦 · B. I. Sidorenko

    In this work, within the framework of the Glauber-Sitenko approximation, an analysis of the differential cross section for deuteron breakup into a proton in the reaction H(d,p)X is presented. The study is carried out using various parameterizations of the deuteron wave function, including the single-Gaussian parametrization, the multi-Gaussian K2 parametrization, and models based on the Av18 and NijmI nucleon-nucleon potentials. Special attention is given to the effects of small longitudinal components of the transferred momentum (Qz < 0.5 GeV/c) and the transverse momentum of the proton-neutron pair (p_perp < 0.5 GeV/c) in the anti-laboratory reference frame. The results are compared with experimental data, particularly in the region of longitudinal momenta p\_3 = 0.25-0.5 GeV/c, where quark effects are expected to manifest. Preliminary estimates show a decrease in the cross section with increasing transverse momentum, as well as a relatively small shift (and growth) of the cross-section maximum due to the inclusion of the longitudinal component Qz.

    hep-phnucl-thNucl.Phys.Atom.Energy(2026)·1 citation
25. 25*

    Single-valued periods of meromorphic modular forms and a motivic interpretation of the Gross-Zagier conjecture

    Francis Brown · Tiago J. Fonseca

    A well-known conjecture of Gross and Zagier states that the values of the higher automorphic Green's function at pairs of points with complex multiplication in the upper half-plane are proportional to the logarithm of an algebraic number. It was recently settled in the case of congruence subgroups of the form ${\Gamma }_0(N)$ by analytic methods. In this paper we provide a geometric and motivic interpretation of the general conjecture, and show that it is a consequence of a standard conjecture in the theory of motives. In addition, we define a new class of matrix-valued higher Green's functions for both odd and even weight modular forms, and show that they are single-valued periods of a motive constructed from a suitable moduli stack of elliptic curves with marked points. The motive has the structure of a biextension involving symmetric powers of the motives of elliptic curves. This suggests a very general extension of the Gross-Zagier conjecture relating values of matrix-valued higher Green's functions at points which do not necessarily have complex multiplication to special values of $L$-functions. In particular, our motivic interpretation of the Gross-Zagier log-algebraicity conjecture enables us to give a completely geometric proof in level 1 and weight 4 by showing that the motive of the moduli stack ${\mathcal{M}}_{1,3}$ of elliptic curves with 3 marked points is mixed Tate. In the course of this paper we develop many new foundational results on: the theory of weak harmonic lifts, meromorphic modular forms, biextensions of modular motives, and their corresponding algebraic de Rham cohomology and single-valued periods, which may all be of independent interest.

    ↳ math.NThep-phmath.AG2 citations
26. 26*

    Scalar and spinor fields in gravitating cosmic string spacetimes

    Marcos Silva🇧🇷 · Azadeh Mohammadi🇧🇷

    We study the scattering behavior of scalar and spinor fields in the background of a gravitating cosmic string spacetime. The model explored here for the background vortex is non-abelian, becoming abelian in an appropriate limiting case. We adopted the formalism we developed in \cite{silva2021scattering}, modifying the standard partial wave approach. We apply the method for a scalar and also a fermion field interacting with the background spacetime with a nontrivial asymptotic structure. The spacetime metric, obtained numerically in \cite{de2015gravitating}, forms the basis of our state-of-the-art numerical study. We make an exhaustive analysis and compare all the results in the non-abelian model with the corresponding abelian one for both massless and massive fields. We analyze the field configuration's total cross-section and angular profile at small and large distances from the core. We show that the total cross-section oscillates with the incident momentum of the wave, as anticipated in \cite{silva2021scattering}, and also, the angular profile can be explained reasonably well with a Fraunhofer diffraction pattern, especially for the scalar field scattering.

    ↳ hep-thgr-qchep-phquant-phClass.Quant.Grav.(2025)·0 citations
27. 27*

    Acausality-driven instabilities in transient relativistic viscous hydrodynamics

    Lorenzo Gavassino🇬🇧 · Henry Hirvonen🇺🇸 · Jean-François Paquet🇺🇸 · Mayank Singh🇺🇸 · Gabriel Soares Rocha🇧🇷

    We investigate non-linear instabilities stemming from superluminal propagation of information in Israel-Stewart-like models of relativistic viscous fluid dynamics. In relativity, the characteristic speed of propagation of information, $w$, and the speed of the fluid, $v$, allow us to differentiate between regimes of the hydrodynamic equations that are acausal but stable ($w>1$), unstable ($v^2{w}^2\ge 1$), and covariantly ill-posed ($w^2\le 0$). As an analytical benchmark, we present a new solution that illustrates these distinct regimes. We compare this analytical solution to the result of a numerical relativistic viscous fluid dynamics solver, and confirm that the analytical result can be recovered numerically in the stable regime, whether causal or acausal. The onset of numerical instabilities is further found to occur in the regime predicted by the analytical solution.

    ↳ nucl-thhep-phPRD(2025)·5 citations
28. 28*

    Long-Range $N-J/\psi$ Interaction from an Operator Product Expansion Perspective

    Seokwoo Yeo🇰🇷 · In Woo Park🇰🇷 · Su Houng Lee🇰🇷

    A recent lattice QCD study has shown that the $N-J/\psi$ potential is attractive at all distances, and its long-range tail is well described by two-pion exchange. Here, we study to what extent the long-range part of the attraction can be reproduced from the perspective of the operator product expansion (OPE). This is accomplished by extracting the leading-order four-quark operator that couples to two pions and calculating its contribution to the $J/\psi$ mass in nuclear matter, to linear order in density, within the QCD sum rule framework. Using previous estimates of the four-quark operators for the chiral symmetric and breaking parts, we obtain a mass decrease that is smaller in magnitude but qualitatively consistent with the attraction obtained in the lattice QCD calculation. By expressing the interaction in terms of four-quark operators, we can analyze the effects of chiral symmetry restoration in dense matter on the masses of the $J/\psi$ and other mesons composed of heavy quarks.

    ↳ nucl-thhep-phPRD(2025)·2 citations
29. 29*

    Multiplicity dependence of the entropy and heat capacity for pp collisions at LHC energies

    C. E. Munguía López🇲🇽 · D. Rosales Herrera🇲🇽 · J. R. Alvarado García🇲🇽 · A. Fernández Téllez🇲🇽 · J. E. Ramírez🇲🇽

    We investigate the multiplicity dependence of the transverse momentum spectrum of the charged particle production in pp collisions at LHC energies. To this end, we consider the experimental data sets classified with different multiplicity estimators, defined by the ALICE Collaboration, that are analyzed within the framework of nonextensive particle production. We compute the variance, kurtosis, Shannon entropy, and heat capacity of the $p_T$ spectrum to study the hardening process as a function of the multiplicity and temperature under the different event classifiers. We found that both the Shannon entropy and the heat capacity show different responses for the triggers at the forward-backward and midrapidity regions. We emphasize that the selection of event biases may induce different responses in estimating theoretical and phenomenological observables that could lead to misleading conclusions.

    ↳ hep-exhep-phRev.Mex.Fis.(2026)·2 citations
30. 30*

    Probing surface vibration of spherical nuclei in relativistic heavy-ion collisions

    Kouichi Hagino🇯🇵 · Masakiyo Kitazawa🇯🇵

    There has been increasing interest in recent years in using relativistic heavy-ion collisions to probe nuclear structure, such as static nuclear deformation. Here we discuss the role of quantum zero-point fluctuations of the surface vibration of spherical nuclei in relativistic heavy-ion collisions. To this end, we employ an approach to describe the vibration in the space-fixed frame, which has been well established in the field of low-energy heavy-ion fusion reactions. We particularly consider the quadrupole vibration of ${}^{58}$Ni in ${}^{58}$Ni+${}^{58}$Ni reaction and the octupole vibration of ${}^{208}$Pb in ${}^{208}$Pb+${}^{208}$Pb reaction. We show that the surface vibration leads to comparable eccentricity parameters to those for static deformation, while they give significantly different distributions of the initial states, suggesting the importance of the proper treatment of the surface vibration in heavy-ion collisions. We perform similar analysis also for triaxial deformation and gamma-soft vibration.

    ↳ nucl-thhep-phnucl-exPRC(2025)·10 citations
31. 31*

    A Resummed Hydrodynamic Description of Relativistic Heavy-ion Collisions

    Cheng Chiu🇺🇸 · Gabriel Denicol🇧🇷 · Matthew Luzum🇧🇷 · Chun Shen🇺🇸

    We introduce a resummed hydrodynamic scheme for evolving the viscous stress tensors in relativistic viscous hydrodynamics, based on which the necessary non-linear causality conditions can be imposed. When the magnitudes of the shear and bulk viscous stress tensors are small relative to the ideal part energy-momentum tensor, this new resummed scheme reduces to the standard second-order relativistic hydrodynamic theories. Nontrivial nonlinear corrections from high-order gradient terms retain the sizes of shear and bulk viscous stress tensors within tunable maximum allowed values. We perform event-by-event simulations for Pb+Pb and p+Pb collisions at 5.02 TeV to quantify the theoretical uncertainties from this resummed scheme on final-state flow observables.

    ↳ nucl-thhep-ph2 citations
32. 32*

    Cosmic string gravitational wave backgrounds at LISA: I. Signal survey, template reconstruction, and model comparison

    Androniki Dimitriou🇪🇸 · Daniel G. Figueroa🇪🇸 · Peera Simakachorn🇪🇸 · Bryan Zaldivar🇪🇸

    We present a catalog of gravitational wave background (GWB) signal templates from cosmic-string networks, based on relevant models proposed in the literature. We classify templates as conventional, based on standard cosmology and Nambu-Goto results (VOS and BOS), and beyond conventional, based on modifications of a) the loop number density (LRS, super, metastable, current-carrying strings), b) the expansion history (non-standard cosmologies, extra degrees of freedom, either thermal or secluded), or c) the loop properties (birth length, power emission). Using the SBI package $\text{GWBackFinder}$, we quantify the reconstruction precision of each signal by LISA, scanning over their parameter space, and performing model comparisons. For conventional signals, LISA reconstructs the tension $G\mu$ with an error $\lesssim 10\%$ for $G\mu \gtrsim 5\cdot 10^{-15}$, which decreases down to $2-3\%$ for $G\mu \gtrsim 10^{-12}$. BOS and VOS modelings become distinguishable confidently for $G\mu \gtrsim 5\cdot 10^{-13}$. For beyond-conventional signals, we identify SNR and error-threshold intervals for each parameter, and determine (for few examples) the regions where they can be distinguished from conventional signals. Analogous quality reconstruction studies of cosmic-string GWBs, superimposed over leading astrophysical foregrounds in the LISA window, will be presented in a series of upcoming papers.

    ↳ astro-ph.COgr-qchep-phJCAP(2026)·11 citations
33. 33*

    Non-perturbative determination of meson masses and low-energy constants in large-$N$ QCD

    Claudio Bonanno🇪🇸 · Margarita García Pérez🇪🇸 · Antonio González-Arroyo🇪🇸 · Ken-Ichi Ishikawa🇯🇵 · Masanori Okawa🇯🇵

    We provide first-principles non-perturbative determinations of the low-lying meson mass spectrum of large-$N$ QCD in the 't Hooft limit $N_{\mathrm{f}}/N\to 0$, as well as of three low-energy constants appearing in the QCD chiral expansion: the quark condensate $\Sigma$, the pion decay constant $F_{\pi }$, and the next-to-leading-order coupling ${\bar{\ell }}_4$. Using the excited state masses in the $\pi$ and $\rho$ channels, we are able to investigate the behavior of their radial Regge trajectories. Concerning QCD low-energy constants, we are able to assess the magnitude of sub-leading corrections in $1/N$ by combining our $N=\infty$ results with previous finite-$N$ determinations. Our calculation exploits large-$N$ twisted volume reduction to efficiently perform numerical Monte Carlo simulations of the large-$N$ lattice discretized theory. We employ several values of $N$ up to $N=841$, 5 values of the lattice spacing, and several values of the quark mass, to achieve controlled continuum and chiral extrapolations.

    ↳ hep-lathep-phhep-thJHEP(2025)·11 citations
34. 34*

    Flavour interferometry in Reissner-Nordstrom background

    Jean Alexandre🇬🇧 · Emilio Meryn🇬🇧

    We derive the phase acquired by a neutral scalar particle propagating along Reissner-Nordstrom geodesics. Considering two flavours propagating on different trajectories which intersect, we plot the interference pattern induced by gravitational lensing from the charged compact object. Although the effect of the charge is subdominant in the metric, it proves to be significant in the phase, and shifts the interference pattern, compared to the Schwarzschild case. This pattern is characterised by two oscillation lengths which, if known, would allow the determination of both eigen masses independently.

    ↳ gr-qcastro-ph.HEhep-phPRD(2025)·2 citations
35. 35*

    On the Determination of Collisional Stopping Power via Kaluza-Klein Theory

    Seyda Elife Gönül🇹🇷 · Huriye Gürsel🇹🇷

    In this work, the tools of general relativity are used to analytically derive collisional stopping power and a linkage between higher-dimensional field theory and transport phenomena is proposed. We start from a Kaluza-Klein inspired, five-dimensional diffeomorphism-invariant action, and upon compactification, obtain a four-dimensional effective theory in which the matter fields are treated to be brane-localized. The medium response to the projected electron is encoded in symmetric tensor fields coupled covariantly to both electromagnetic and fermionic parts via Lagrangian-derived interactions. When $R_c\sim {\Lambda }_{\text{EM}}^{-1}$, ${\Lambda }_{\text{EM}}\gg m_e$ and $g_4^2=\frac{3{\pi }^2{m}_{e}v}{4{\gamma }^3{R}_c^2{e}^2{\Lambda }_{\text{EM}}}$ are satisfied, the leading term of Bethe-Møller formula is shown to be recovered in the large $R$ limit. The construction presented here may serve as an alternative approach that uses compactification geometry and medium excitations to determine observable couplings and stopping power. The model intrinsically supports phenomena linked to anisotropy and nonlinear response, as well as gravitational or extra-dimensional effects in laboratory-scale systems via the study of stopping power and particle range. The construction is gauge invariant, behaves consistently under limiting conditions, and can be matched to experimental stopping data through a single effective normalization constant.

    ↳ gr-qccond-mat.otherhep-phhep-th0 citations
36. 36*

    Mean free path of photons in relativistic heavy ion collisions

    Jajati K. Nayak · Rupa Chatterjee

    Electromagnetic probes, such as photons and dileptons, play a key role in diagnosing the initial temperature of the hot and dense quark-gluon plasma (QGP) matter created in relativistic nuclear collisions at very high energies. This is due to their large mean free path $\lambda$, which allows them to escape the medium without significant interactions. Unlike hadronic particles, which experience multiple scatterings and are affected by the evolving medium, electromagnetic probes carry undistorted information from the initial stages of the expanding system. In this work an attempt has been made to revisit the estimation of mean free paths of photons in QGP phase for a temperature range predicted by hydrodynamics for heavy ion collisions at $\sqrt{s_{NN}}=200$ GeV at RHIC and $\sqrt{s_{NN}}=2.76$ TeV at the LHC. The mean free paths have been estimated for a plasma expanding via (1+1)D and (2+1)D hydrodynamical expansions. For the (1+1)D case, photons with low energy ($E_{\gamma }<0.2$ GeV) coming from a high temperature ($>250$ MeV) source are found to have shorter mean free path compared to the expansion scale of the system; while the high energy photons have always larger mean free paths. A similar qualitative nature of the mean free path has also been observed for a more realistic (2+1)D hydrodynamic model calculations although the $\lambda$ values are found to be larger on a quantitative scale compared to the (1+1)D case.

    ↳ nucl-thhep-exhep-phIJMPE(2025)·11 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.