Tue·Mar 5, 2024Tuesday·March 5, 2024

1. 01*

   Heavy neutral lepton search and $\mu \to e\gamma$ constraints in case of type-I seesaw

   Stefano Morisi🇮🇹

   Within type-I seesaw mechanism it is possible to have large (order one) light-heavy neutrino mixing even in case of low right-handed neutrino mass scale (of the order of GeV). This implies large lepton flavor violation. As example we consider the process $\mu \to e\gamma$ that can have a branching up to $10^{-8}$ within type-I seesaw (in contrast with the tiny value $10^{-54}$ expected). Such an enhancing of lepton flavor violation can be used to constraint the parameter space of long lived particle experiments.

   hep-phhep-exSymmetry(2024)·5 citations
2. 02*

   Strangeness plus-one ($S=+1$) resonance-state $P_0^{+\ast }$ via $K^{+}n\to K^{\ast 0}p$

   Dayoung Lee🇰🇷 · Seung-il Nam🇰🇷

   In our current study, we delve into the peak-like structure observed during the reaction process of $K^{+}n\to K^{0}p$ at approximately $\sqrt{s}\sim 2.5$ GeV. Our focus centers on exploring the potential $S=+1$ resonance $P_0^{+\ast }\equiv P_0^{\ast }$ as an excited state within the extended vector-meson and baryon ($VB$) antidecuplet. To achieve this aim, we employ the effective Lagrangian method in conjunction with the $(u,t)$-channel Regge approach, operating within the tree-level Born approximation. We thoroughly examine various spin-parity quantum numbers for the resonance, resulting in a compelling description of the data, where $M_{P_0^{\ast }}\approx 2.5$ GeV and ${\Gamma }_{P_0^{\ast }}\approx 100$ MeV. Furthermore, we propose an experimental technique to amplify the signal-to-noise ratio ($S/N$) for accurately measuring the resonance. Notably, our findings reveal that background interference diminishes significantly within the $K^{\ast }$ forward-scattering region in the center-of-mass frame when the $K^{\ast }$ is perpendicularly polarized to the reaction plane. Additionally, we explore the recoil-proton spin asymmetry to definitively determine the spin and parity of the resonance. This study stands to serve as a valuable reference for designing experimental setups aimed at investigating and comprehending exotic phenomena in QCD. Specifically, our insights will inform future J-PARC experiments, particularly those employing higher kaon beam energies.

   hep-phnucl-exnucl-thPRC(2024)·2 citations
3. 03*

   Study of identified particle production as a function of transverse event activity classifier, $S_T$ in p$-$p collisions

   Rahul Verma🇮🇳 · Vishu Saini🇮🇳 · Basanta Nandi🇮🇳 · Sadhana Dash🇮🇳

   A new observable, $S_T$, is introduced in terms of the sum of the transverse momentum of charged particles (${\sum }_i{p}_{T_i}$ ) produced in proton proton (p$-$p) collisions at LHC energies to probe the underlying events (UE). The UE are defined as those aspects of proton-proton collisions that are not attributed to the primary hard scattering process, but rather to the accompanying interactions of the rest of the proton. The conventional approach of studying underlying events is usually carried out by defining topological regions with respect to the leading particle in an event. The transverse region is generally sensitive to UE and various classifiers have been used to discriminate the extent of UE activity regions. The production of identified particles like ${\pi }^{\pm }$, $K^{\pm }$, p , $K_S^0$, and ${\Lambda }^0$ are studied in different ranges of transverse activity classifier in p$-$p collisions at $\sqrt{s}=13$ TeV using pQCD inspired PYTHIA 8 event generator. A comparative analysis of the identified particle spectra, mean multiplicity and mean transverse momentum has been carried out with respect to $S_T$ and the performance of this new observable is gauged by comparing the results with previously defined $R_T$ observable.

   hep-phnucl-thEur.Phys.J.Plus(2025)·2 citations
4. 04*

   Analyzing the transport coefficients and observables of a rotating QGP medium in kinetic theory framework with a novel approach to the collision integral

   Shubhalaxmi Rath🇨🇱 · Sadhana Dash🇮🇳

   In the present work, we have studied how the rotation of the QGP medium affects the transport coefficients and observables in heavy ion collisions. For the noncentral collisions, although most of the angular momentum gets carried away by the spectators, there still remains a finite angular momentum with a finite range of angular velocity, which thus incites rotation in the produced matter. As a result, various properties of the QGP medium including its transport properties are most likely to be modulated by the rotation. We have calculated the transport coefficients and observables, such as the electrical conductivity, the thermal conductivity, the Knudsen number, the elliptic flow, the specific heat at constant pressure, the specific heat at constant volume, the trace anomaly, the thermal diffusion constant and the isothermal compressibility using the kinetic theory to see the effect of rotation on them. In particular, we have used the novel relaxation time approximation for the collision integral in the relativistic Boltzmann transport equation to derive the transport coefficients and compared them with their values in the relaxation time approximation within the kinetic theory approach in conjunction with the finite angular velocity. We have found that the emergence of angular velocity enhances the flow of charge and heat in the medium. Further, as compared to the relaxation time approximation, the electrical and the thermal conductivities have smaller values in the novel relaxation time approximation and these differences between the conductivities in the said approximations are more pronounced at high temperatures than at low temperatures. Furthermore, all the aforesaid observables are found to be sensitive to the rotation of the QGP medium.

   hep-phhep-thnucl-thEPJC(2025)·7 citations
5. 05*

   Electroweak Phase Transition in Singlet Extensions of The Standard Model with Dimension-Six Operators

   V.K. Oikonomou🇬🇷 · Apostolos Giovanakis🇬🇷

   The significance of the electroweak phase transition is undeniable, and although initially it was believed that it was second-order, it is now believed that it is a first-order transition. However, it is not a strong first-order phase transition in the context of the Standard Model and the remedy to this issue is to use the Higgs portal and directly couple the Higgs to a hidden scalar sector. This can result in a strong electroweak phase transition, while the couplings to a hidden scalar are constrained by several phenomenological constraints, such as the sphaleron rate criterion and the branching ratio of the Higgs to invisible channels. In this work, we consider the standard singlet extensions of the Standard Model, including dimension-six non-renormalizable operators that couple a real singlet scalar field with the Higgs doublet. As a result, we examine the effects of those Higgs-singlet couplings on the electroweak phase transition. The effective theory, where the non-renormalizable couplings originate from, is considered to be active beyond 15TeV. As we show, the Universe experiences a two-step electroweak phase transition, a primary phase transition in the singlet sector at a high temperature, and then a subsequent first-order phase transition from the singlet vacuum to the electroweak vacuum. The singlet's phase transition can either be second-order or first-order, depending on the singlet mass and its couplings to the Higgs. In particular, we show that the dimension-six operator assists in generating a strong electroweak phase transition in regions of the parameter space that were excluded in the previous singlet extensions of the Standard Model. This is further apparent for low singlet masses \(m_S < m_H/2\) which are rarely taken into account in the literature due to the invisible branching ratio of the Higgs boson.

   hep-phastro-ph.COgr-qchep-thPRD(2024)·26 citations
6. 06*

   MeV gamma rays from Q-ball decay

   Shinta Kasuya🇯🇵 · Masahiro Kawasaki🇯🇵 · Naomi Tsuji🇯🇵

   We study the supersymmetric Q balls which decay at present and find that they create a distinctive spectrum of gamma rays at around O(10) MeV. The charge of the Q ball is lepton numbers in order for the lifetime to be as long as the present age of the universe, and the main decay products are light leptons. However, as the charge of the Q ball decreases, the decay channel into pions becomes kinematically allowed towards the end of the decay, and the pions are produced at rest. Immediately, ${\pi }^0$ decays into two photons with the energy of 67.5 MeV, half the pion mass, which exhibits a unique emission line. In addition, ${\pi }^{\pm }$ decay into ${\mu }^{\pm }$, which further decay with emitting internal bremsstrahlung, whose spectrum has a sharp cutoff at $\sim$50 MeV. If the observations would find these peculiar features of the gamma-ray spectrum in the future, it could be a smoking gun of the supersymmetric Q-ball decay at present.

   hep-phastro-ph.COastro-ph.HEPRD(2024)·6 citations
7. 07*

   Production of $X_b$ via radiative transition of ${\rm Y}(10753)$

   Shi-Dong Liu (1)🇨🇳 · Hao-Dong Cai (1)🇨🇳 · Zu-Xin Cai (1 and 2)🇨🇳 · Hong-Shuo Gao (1)🇨🇳 · Gang Li (1)🇨🇳 · Fan Wang (1)🇨🇳 · Ju-Jun Xie (2 and 3 and 4) ((1) College of Physics and Engineering, Qufu Normal University, Qufu, China, (2) Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China, (3) School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing, China, (4) Southern Center for Nuclear-Science Theory (SCNT), Institute of Modern Physics, Chinese Academy of Sciences, Huizhou, China)🇨🇳

   We studied the radiative transitions between the ${\rm Y}(10753)$, the $S$-$D$ mixed state of the ${\rm Y}(4S)$ and ${{\rm Y}}_1(3{}^3{D}_1)$, and the $X_b$, the heavy quark flavor symmetry counterpart of the $X(3782)$ in the bottomonium sector. The radiative transition was assumed to occur through the intermediate bottom mesons, including $P$-wave $B_1^{(\prime )}$ mesons as well as the $S$-wave $B^{(\ast )}$ ones. The consideration of the $B_1^{(\prime )}$ mesons leads to the couplings to be in $S$-wave, and hence enhances the contributions of the intermediate meson loops. The radiative decay width for the ${\rm Y}(10753)\to \gamma X_b$ is predicted to be order of $10\mathrm{keV}$, corresponding to a branching fraction of $10^{-4}$. Based on the theoretical results, we strongly suggest to search for the $X_b$ in the $e^{+}{e}^{-}\to \gamma X_b$ with $X_b\to \pi \pi {\chi }_{b1}$ near $\sqrt{s}=10.754\mathrm{GeV}$, and it is hoped that the calculations here could be tested by the future Belle II experiments.

   hep-phPRD(2024)·8 citations
8. 08*

   Elliptic anisotropy of open-charm hadrons from parton scatterings in p--Pb collisions at energies available at the CERN Large Hadron Collider

   Siyu Tang🇨🇳 · Yuan Lu🇨🇳 · Chao Zhang🇨🇳 · RenZhuo Wan🇨🇳

   The elliptic azimuthal anisotropy coefficient ($v_2$) of open-charm hadron at midrapidity ($|\eta <1|$) was studied in p--Pb collisions at $\sqrt{s_{\mathrm{NN}}}=$ 8.16 TeV using a multi-phase transport (AMPT) model included an additional charm quark--antiquark pair production trigger. The model provides a simultaneously description of the measured $p_{\mathrm{T}}$ spectrum and $v_2$ of $D^0$ meson, as well as the $v_2$ of light flavor meson $K_s^0$. We found that the $D^0$ and $K_s^0$ $v_2$ are both significantly affected by different parton scatterings among charm and light quarks. In addition, the predictions for the $v_2$ of other charm hadrons including $D^{+}$, $D_s^{+}$ and ${\Lambda }_c^{+}$ in p--Pb collisions are given for the first time. The $v_2$ of open-charm hadron reasonably follows the number-of-constituent-quark (NCQ) scaling up to 2.5 GeV, strongly indicating the importance of partonic degrees of freedom for the collectivity of heavy flavors in high-multiplicity p--Pb collisions. These findings may hint the formation of deconfined matter in small collision systems, and provide referential value for future measurements of azimuthal anisotropy at the LHC energies.

   hep-phPRC(2024)·4 citations
9. 09*

   Asymmetric Dark Matter and Sommerfeld Enhancement

   Sujuan Qiu🇨🇳 · Hoernisa Iminniyaz🇨🇳 · Wensheng Huo🇨🇳

   We show that the relic density of asymmetric dark matter with long-range interactions is affected by the Sommerfeld enhancement. The annihilation cross section of asymmetric dark matter is enhanced due to the Sommerfeld effect. It results the relic density is decreased. Using the Planck date, the constraints on the asymmetry factor and coupling required to attain the observed dark matter density are obtained. We derive the upper bounds on the mass for asymmetric dark matter in s-wave and p-wave annihilation cases.

   hep-phCommun.Theor.Phys.(2024)·2 citations
10. 10*

    Extranatural Warped Inflation

    Toshiki Kawai · Yoshiharu Kawamura🇯🇵

    We investigate whether inflation in the early universe can be induced by an extra component of a five-dimensional $\mathrm{U}(1)$ gauge field in the Randall-Sundrum warped spacetime or not. We show that an effective potential obtained by quantum corrections can act as an inflaton potential by finding parameter regions consistent with Planck 2018 results. In our model, fields involved in inflation obey a different type of boundary condition from that of the visible particles, and a surviving Wilson line phase can play a specific role for physics beyond the standard model.

    hep-phhep-th0 citations
11. 11*

    Identification of the $G(3900)$ as the P-wave $D{\bar{D}}^{\ast }/\bar{D}{D}^{\ast }$ resonance

    Zi-Yang Lin🇨🇳 · Jun-Zhang Wang🇨🇳 · Jian-Bo Cheng🇨🇳 · Lu Meng🇩🇪 · Shi-Lin Zhu🇨🇳

    The BESIII Collaboration recently performed a precise measurement of the $e^{+}{e}^{-}\to D\bar{D}$ Born cross sections, and confirmed the $G(3900)$ structure reported by BaBar and Belle with high significance. We identify the $G(3900)$ as the first P-wave $\text{DDbar}$ molecular resonance. The experimental and theoretical identification of the P-wave dimeson state holds paramount importance in enhancing our comprehension of the non-perturbative QCD and few-body physics. Its existence is firmly established in a unified meson-exchange model which simultaneously depicts the features of the ${\chi }_{c1}(3872)$, $Z_c(3900)$ and $T_{cc}(3875)$. This scenario can be directly examined in the $e^{+}{e}^{-}\to D{\bar{D}}^{\ast }/\bar{D}{D}^{\ast }$ cross section by seeing whether a resonance exists at the threshold. The credibility of the investigations is also ensured by the fact that the P-wave interaction dominantly arises from the well-known long-range pion exchange. Additionally, thanks to the centrifugal barrier, it is easier to form resonances in P-wave than in S-wave. We extensively calculate all systems up to P-wave with various quantum numbers and predict a dense population of the $\text{DDbar}$ and $\text{DD}$ states, where the S-wave $\text{DDbar}$ state with $I^G(J^{PC})=0^{-}(1^{+-})$, P-wave $\text{DDbar}$ state with $I^G(J^{PC})=0^{+}(0^{-+})$, and P-wave $\text{DD}$ state with $I(J^P)=0(0^{-})$ are more likely to be observed in experiments.

    hep-phhep-exhep-latnucl-thPRL(2024)·35 citations
12. 12*

    Dark matter semi-annihilation for inert scalar multiplets

    Hugues Beauchesne🇹🇼 · Cheng-Wei Chiang🇹🇼

    Dark matter semi-annihilation is a process through which two dark matter candidates annihilate to a single dark matter particle and a non-dark matter particle. Such processes are common when the symmetry stabilizing the dark matter differs from ${\mathbb{Z}}_2$ and can lead to qualitatively different phenomenology. In this work, we study the viability of semi-annihilation models including one or two inert multiplets. For one multiplet, we show that there does not exist any viable model in which semi-annihilation is efficient. For two multiplets, semi-annihilation can be efficient, but the number of viable and technically natural models is limited. We then perform a detailed study of the most promising model, showing that the correct relic abundance can be obtained for a wide range of masses.

    hep-phJHEP(2024)·5 citations
13. 13*

    Rotation effect on the deconfinement phase transition in holographic QCD

    Jia-Hao Wang🇨🇳 · Sheng-Qin Feng🇨🇳

    The impact of rotation on the deconfinement phase transition under the EM system of the soft and the hard wall models in holographic QCD is studied in this paper. The metric by cylindrical coordinates with rotation is introduced into the system to calculate the Hawking temperature. The first holographic study on the influence of the radius of a homogeneous rotating system on the phase diagram is proposed. It is found that the phase transition temperature hardly changes with the rotation angular velocity for a small rotation radius. Only with a larger rotation radius can the change in rotational angular velocity significantly alter the phase transition temperature. The phase transition temperature decreases rapidly with the increase of rotation angular velocity as the rotation radius increases.

    hep-phPRD(2024)·27 citations
14. 14*

    Charged particle multiplicity fluctuation in $A-A$ collisions at RHIC and LHC energies using Angantyr model

    Pritindra Bhowmick🇮🇳 · Sadhana Dash🇮🇳 · Basanta Nandi🇮🇳 · Claude Pruneau🇺🇸

    Event-by-event fluctuations of the charged particle multiplicity are studied for a wide range of centralities for Au$-$Au collisions at $\sqrt{s_{NN}}$ = 200 GeV, Pb$-$Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV and 5.02 TeV using the Pythia 8 Angantyr model. The centrality dependence of ${\omega }_{ch}$ observable, which quantifies the fluctuations in terms of scaled variance is studied for different pseudorapidity ranges and has been compared with those obtained from a simple participant superposition model. The ${\omega }_{ch}$ was found to be lower than the expectations from the participant model. The estimate would act like a baseline for current and future measurements of event-by-event fluctuations in the charged particle multiplicities in systems at LHC energies where no de-confined medium of quarks and gluons are formed.

    hep-phEur.Phys.J.Plus(2025)·0 citations
15. 15*

    Double-mixing CP violation in $B$ decays

    Wen-Jie Song🇨🇳 · Yin-Fa Shen🇨🇳 · Qin Qin🇨🇳

    We study a long-overlooked CP violation observable, termed double-mixing CP violation, which arises from the interference between two neutral meson oscillating paths involved in a decay chain. The double-mixing CP violation is beneficial for the precise test of the Standard Model CKM mechanism, as it offers the potential to extract weak phases without pollution from strong dynamics. To provide a comprehensive understanding of the double-mixing CP violation, we perform phenomenological analyses on the cascade decays of the $B_d^0$ and $B_s^0$ mesons. Our results show that the double-mixing CP violation can be very significant in certain decay channels, such as $B_s^0\to {\rho }^{0}K\to {\rho }^0({\pi }^{-}{\ell }^{+}{\nu }_{\ell })$. In addition, we employ the decay process $B_d^0\to D^{0}K\to (K^{-}{\pi }^{+})(\pi \ell \nu )$ to demonstrate that the involved strong and weak phases can be directly determined from the experimental data without any theoretical inputs.

    hep-phEPJC(2024)·7 citations
16. 16*

    Examining the critical phenomenon of pion parton distribution: Insights from the Moment Problem

    Xiaobin Wang🇨🇳 · Zexin Wu🇨🇳 · Minghui Ding🇩🇪 · Lei Chang🇨🇳

    A recent study by Wang {\it et al.}(arXiv:2309.01417) proposed a novel connection between the nature of the parton distribution function (PDF) and the characteristics of its moments. In this study, we apply these findings to analyze the evolution of the pion valence quark PDF, garnering valuable qualitative insights. Firstly, we validate the non-negativity and continuity of the PDF across a wide range of scales, indicating the logical consistency of our chosen evolution scheme. Subsequently, we examine the unimodality of both the PDF and its transformed counterpart, the xPDF, i.e., the parton distribution function multiplied by the momentum fraction. We observe a smooth evolution of the peak position of the xPDF towards the small-$x$ region with increasing scale, while intriguingly, the PDF undergoes a phase of bimodal competition as the energy scale evolves.

    hep-ph0 citations
17. 17*

    Single charged Higgs pair production in exclusive processes at the LHC

    Laura Duarte🇧🇷 · Victor P. Goncalves🇧🇷 · Daniel E. Martins🇵🇱 · Téssio B. de Melo🇨🇱

    The production of a single charged Higgs boson pair by photon - photon interactions in $pp$ collisions at the LHC is investigated in this exploratory study. We focus on the exclusive production, which is characterized by intact protons and two - rapidity gaps in the final state, and assume the type - I two - Higgs - doublet model, which still allows a light charged Higgs. Assuming the leptonic $H^{\pm }\to [\tau {\nu }_{\tau }]$ decay mode, we derive predictions for the transverse momentum, rapidity and invariant mass distributions of the ${\tau }^{+}{\tau }^{-}$ pair for different values of the charged Higgs mass. The contributions of different background processes are also estimated. Our results indicate that the contribution of the exclusive $H^{+}{H}^{-}$ production for the $[{\tau }^{+}{\nu }_{\tau }][{\tau }^{-}{\nu }_{\tau }]$ final state is non - negligible and can, in principle, be used to searching for a light charged Higgs.

    hep-phhep-exEPJC(2024)·5 citations
18. 18*

    A Global View of the EDM Landscape

    Skyler Degenkolb🇩🇪 · Nina Elmer🇩🇪 · Tanmoy Modak🇩🇪 · Margarete Mühlleitner🇩🇪 · Tilman Plehn🇩🇪

    Permanent electric dipole moments (EDMs) are sensitive probes of the symmetry structure of elementary particles, which in turn is closely tied to the baryon asymmetry in the universe. A meaningful interpretation framework for EDM measurements has to be based on effective quantum field theory. We interpret the measurements performed to date in terms of a hadronic-scale Lagrangian, using the SFitter global analysis framework. We find that part of this Lagrangian is constrained very well, while some of the parameters suffer from too few high-precision measurements. Theory uncertainties lead to weaker model constraints, but can be controlled within the global analysis.

    hep-phnucl-thSciPost Phys.(2026)·18 citations
19. 19*

    Constraints from the Neutron EDM on Subleading Effective Operators for Direct Dark Matter Searches

    Manuel Drees🇩🇪 · Rahul Mehra🇩🇪

    Interactions between Dark Matter (DM) and nucleons relevant for direct search experiments can be organised in a model independent manner using a Galiliean invariant, non--relativistic effective field theory (NREFT). Here one expands the interactions in powers of the momentum transfer $\vec{q}$ and DM velocity $\vec{v}$. This approach generates many operators. The potentially most important subleading operators are odd under $T$, and can thus only be present in a theory with $CP$ violating interactions. We consider two such operators, called ${\mathcal{O}}_{10}$ and ${\mathcal{O}}_{11}$ in the literature, in simplified models with neutral spin$-0$ mediators; the couplings are chosen such that the coefficient of the leading spin independent (SI) operator, which survives for $\vec{v}\to 0$, vanishes at tree level. However, it is generically induced at the next order in perturbation theory. We perform a numerical comparison of the number of scattering events between interactions involving the $T-$odd operators and the corresponding loop induced SI contributions. We find that for ''maximal'' $CP$ violation the former can dominate over the latter. However, in two of the three models we consider, an electric dipole moment of the neutron (nEDM) is induced at two--loop order. We find that the experimental bound on the nEDM typically leads to undetectably small rates induced by ${\mathcal{O}}_{10}$. On the other hand, the model leading to a nonvanishing coefficient of ${\mathcal{O}}_{11}$ does not induce an nEDM.

    hep-phhep-exJHEP(2024)·1 citation
20. 20*

    Azimuthal angular correlation of $J/\psi$ plus jet production at the electron-ion collider

    Luca Maxia🇳🇱 · Feng Yuan🇺🇸

    By investigating the soft gluon radiation in the $J/\psi$ plus jet photoproduction at the electron-ion collider (EIC), we demonstrate that the azimuthal angular correlations between the leading jet and heavy quarkonium provide a unique probe to the production mechanism of the latter. In particular, a significant $\cos (\varphi )$ asymmetry is found for the color-singlet channel, whereas it vanishes or has an opposite sign for color-octet production, depending on the jet transverse momentum. Numerical results of $\cos (\varphi )$ and $\cos (2\varphi )$ asymmetries employing both the color-singlet model and the nonrelativistic QCD approach are presented for typical kinematics at the future EIC.

    hep-phhep-exPRD(2024)·11 citations
21. 21*

    The $Z_b$ states as the mixture of the molecular and diquark-anti-diquark components within the effective field theory

    Wei He🇨🇳 · De-Shun Zhang🇨🇳 · Zhi-Feng Sun🇨🇳

    In this study, we reconsider the states $Z_b(10610)$ and $Z_b(10650)$ by investigating the presence of diquark-anti-diquark components as well as the hadronic molecule components in the framework of effective field theory. The different masses of pseudoscalar mesons such as ${\pi }^0$, ${\eta }_8$, and ${\eta }_0$, as well as vector mesons like ${\rho }^0$ and $\omega$ violate the OZI rule that is well depicted under the $[U(3{)}_L\otimes U(3{)}_R{]}_{global}\otimes [U(3{)}_V{]}_{local}$ symmetry. To account for the contribution of intermediate bosons of heavy masses within the OBE model, we introduce an exponential form factor instead of the commonly used monopole form factor in the past. By solving the coupled-channel Schrödinger equation with the Gaussian expansion method, our numerical results indicate that the $Z_b(10610)$ and $Z_b(10650)$ states can be explained as hadronic molecules slightly mixing with diquark-anti-diquark states.

    hep-phhep-exPRD(2024)·8 citations
22. 22*

    QCD Sum Rule study of $J^P=1^{\pm }$ exotic states with two heavy quarks in the molecular picture

    T.M.Aliev🇹🇷 · S.Bilmis🇹🇷 · M.Savci🇹🇷

    In this study, the spectroscopic parameters of the exotic molecular states composed of mesons containing two heavy quarks (scalar-axial and pseudoscalar-axial meson combinations) are investigated within QCD sum rules. Our findings reveal that the molecular states containing charm quarks do not form bound states, whereas the states with b-quarks can form the exotic molecular states. This observation has significant implications for understanding the structure of these exotic states.

    hep-phCPC(2024)·1 citation
23. 23*

    Perturbative QCD meets phase quenching: The pressure of cold quark matter

    Pablo Navarrete🇫🇮 · Risto Paatelainen🇫🇮 · Kaapo Seppänen🇫🇮

    Nonperturbative inequalities constrain the thermodynamic pressure of Quantum Chromodynamics (QCD) with its phase-quenched version, a Sign-Problem-free theory amenable to lattice treatment. In the perturbative regime with a small QCD coupling constant ${\alpha }_s$, one of these inequalities manifests as an $O({\alpha }_s^3)$ difference between the phase-quenched and QCD pressures at large baryon chemical potential. In this work, we generalize state-of-the-art algorithmic techniques used in collider physics in vacuum quantum field theory to address large-scale multiloop computations at finite chemical potential, by direct numerical integration of Feynman diagrams in momentum space. Using this novel approach, we evaluate this $O({\alpha }_s^3)$ difference and show that it is a gauge-independent and small positive number compared to the known perturbative coefficients at this order. This implies that at high baryon densities, phase-quenched lattice simulations can provide a complementary nonperturbative method for accurately determining the pressure of cold quark matter at $O({\alpha }_s^3)$.

    hep-phhep-lathep-thPRD(2024)·20 citations
24. 24*

    Analytic continuations and numerical evaluation of the Appell $F_1$, $F_3$, Lauricella $F_D^{(3)}$ and Lauricella-Saran $F_S^{(3)}$ and their Application to Feynman Integrals

    Souvik Bera🇮🇳 · Tanay Pathak🇮🇳

    We present our investigation of the study of two variable hypergeometric series, namely Appell $F_1$ and $F_3$ series, and obtain a comprehensive list of its analytic continuations enough to cover the whole real $(x,y)$ plane, except on their singular loci. We also derive analytic continuations of their 3-variable generalization, the Lauricella $F_D^{(3)}$ series and the Lauricella-Saran $F_S^{(3)}$ series, leveraging the analytic continuations of $F_1$ and $F_3$, which ensures that the whole real $(x,y,z)$ space is covered, except on the singular loci of these functions. While these studies are motivated by the frequent occurrence of these multivariable hypergeometric functions in Feynman integral evaluation, they can also be used whenever they appear in other branches of mathematical physics. To facilitate their practical use, we provide four packages: AppellF1$.$wl, AppellF3$.$wl, LauricellaFD$.$wl, and LauricellaSaranFS$.$wl in MATHEMATICA. These packages are applicable for generic as well as non-generic values of parameters, keeping in mind their utilities in the evaluation of the Feynman integrals. We explicitly present various physical applications of these packages in the context of Feynman integral evaluation and compare the results using other packages such as FIESTA. Upon applying the appropriate conventions for numerical evaluation, we find that the results obtained from our packages are consistent. Various Mathematica notebooks demonstrating different numerical results are also provided along with this paper.

    hep-phcs.MShep-thmath-ph+1Comput.Phys.Commun.(2025)·12 citations
25. 25*

    The $U$-Matrix geometrical model for multi-particle production in high-energy hadronic collisions

    Rami Oueslati🇧🇪 · Adel Trabelsi🇹🇳

    Inspired by the picture portraying the KNO scaling violation as an extension of the geometrical scaling violation, the current study proposes a phenomenological model for multi-particle production in hadron collisions based on the geometrical approach and using the $U$-Matrix unitarization scheme of the scattering amplitude. The model has been fine-tuned and all parameters have been derived from optimal fits to various hadronic multiplicity distributions data in $p+p(\bar{p})$ collisions across a broad range of energies. The results have revealed that our model furnishes a reasonable description of diverse multiplicity distributions at various energies. Besides, they have demonstrated a pronounced violation of the geometrical scaling, which eventually resulted in a significant violation of the KNO scaling. The study has also analyzed the higher-order moments of the multiplicity distribution. We have observed an unexpected overestimation of the fluctuations and correlations between final state particles with increasing energy, particularly above LHC energy. It is claimed that this overestimation is due to statistical fluctuations embedded in the $U$-matrix scheme. The findings of this study have shed light on the key role of the $U$-matrix scheme in the impact of collision geometry on multi-particle production processes at high energy.

    hep-phJHEP(2024)·3 citations
26. 26*

    Towards a SM prediction for CP violation in charm

    Alexander Lenz🇩🇪 · Maria Laura Piscopo🇩🇪 · Aleksey V. Rusov🇩🇪

    We provide an overview of the current experimental and theoretical status of charm CP violation and discuss recent progress in obtaining a Standard Model prediction for $\Delta a_{\mathrm{CP}}^{\mathrm{dir}}$ using the framework of light-cone sum rules. Furthermore, we present new results for the ratios of the direct CP asymmetries and of the branching fractions for the modes $D^0\to {\pi }^{+}{\pi }^{-}$ and $D^0\to K^{+}{K}^{-}$.

    hep-phhep-exPoS(2024)·5 citations
27. 27*

    On the study of new proxies for second order cumulants of conserved charges in heavy-ion collisions with EPOS4

    Johannes Jahan🇺🇸 · Claudia Ratti🇺🇸 · Maria Stefaniak🇺🇸 · Klaus Werner🇫🇷

    Proxies for cumulants of baryon number $B$, electric charge $Q$ and strangeness $S$ are usually measured in heavy-ion collisions via moments of net-number distribution of given hadronic species. Since these cumulants of conserved charges are expected to be sensitive to the existence of a critical point in the phase diagram of nuclear matter, it is crucial to ensure that the proxies used as substitutes are as close to them as possible. Hence, we use the EPOS4 framework to generate Au+Au collisions at several collision energies of the RHIC Beam Energy Scan. We compute $2^{\text{nd}}$ order net-cumulants of $\pi$, $K$ and $p$, for which experimental data has been published, as well as the corresponding conserved charge cumulants. We then compare them with proxies, defined in previous lattice QCD and Hadron Resonance Gas model studies, which are shown to reproduce more accurately their associated conserved charge cumulants. We investigate the impact of hadronic re-scatterings occurring in the late evolution of the system on these quantities, as well as the amount of signal actually originating from the bulk medium which endures a phase transition.

    hep-phnucl-thPRC(2024)·4 citations
28. 28*

    ee$\in$MC: Comments on Asymmetries in QED

    Ian M. Nugent🇨🇦

    In the Quantum Electrodynamics process $e^{+}{e}^{-}\to l^{+}{l}^{-}(n\gamma )$, there are two well known angular asymmetries in the $cos(\theta )$ and the $cos({\theta }^{\ast })$ distributions. In this paper, the QED angular asymmetry related to the $cos({\theta }^{\ast })$ distribution is investigated in terms of the Dirac propagator and the associated boundary conditions from which the Dirac propagator is constructed and the potential implications are examined.

    hep-phhep-ex0 citations
29. 29*

    Vector Wave Dark Matter and Terrestrial Quantum Sensors

    Dorian W. P. Amaral🇺🇸 · Mudit Jain🇺🇸 · Mustafa A. Amin🇺🇸 · Christopher Tunnell🇺🇸

    (Ultra)light spin-$1$ particles -- dark photons -- can constitute all of dark matter (DM) and have beyond Standard Model couplings. This can lead to a coherent, oscillatory signature in terrestrial detectors that depends on the coupling strength. We provide a signal analysis and statistical framework for inferring the properties of such DM by taking into account (i) the stochastic and (ii) the vector nature of the underlying field, along with (iii) the effects due to the Earth's rotation. Owing to equipartition, on time scales shorter than the coherence time the DM field vector typically traces out a fixed ellipse. Taking this ellipse and the rotation of the Earth into account, we highlight a distinctive three-peak signal in Fourier space that can be used to constrain DM coupling strengths. Accounting for all three peaks, we derive latitude-independent constraints on such DM couplings, unlike those stemming from single-peak studies. We apply our framework to the search for ultralight $B-L$ DM using optomechanical sensors, demonstrating the ability to delve into previously unprobed regions of this DM candidate's parameter space.

    hep-phastro-ph.COJCAP(2024)·39 citations
30. 30*

    Expedition to the Zeptouniverse

    Andrzej J. Buras🇩🇪

    Flavour experiments promise insights into energy scales as high as 200 TeV and distances as small as Zeptometer and offer the chance to identify New Physics

    hep-phhep-exhep-latphysics.pop-ph5 citations
31. 31*

    Cogenesis of baryon and dark matter with PBH and QCD axion

    Debasish Borah🇮🇳 · Nayan Das🇮🇳 · Suruj Jyoti Das🇰🇷 · Rome Samanta🇨🇿

    With entropy injection, an early matter-dominated epoch (EMD) impels the axion decay constant $f_a$ towards larger values to produce correct axion dark matter (DM) abundance, thereby unfolding the low-mass axion ($m_a\lesssim 10^{-5}$ eV) parameter space to be searched for in axion experiments. We implement this proposition in a scenario where $f_a$ and the leptogenesis scale in a seesaw mechanism are equivalent. We show, that if instead, the EMD is provided by evaporating ultralight primordial black holes (PBH), the scenario becomes strikingly testable with gravitational waves (GW) background alongside the axion searches. In particular, while being consistent with correct axion DM abundance, the scale $f_a\gtrsim 10^{12}$ GeV, corresponding to the unflavored regime of leptogenesis with hierarchical right-handed neutrinos, can be probed with GW and axion experiments, which is otherwise not testable at neutrino or collider experiments. Additionally, axions produced from PBH evaporation can give rise to dark radiation within reach of future cosmic microwave background experiments.

    hep-phastro-ph.COPRD(2024)·12 citations
32. 32*

    A New Determination of the Millisecond Pulsar Gamma-Ray Luminosity Function and Implications for the Galactic Center Gamma-Ray Excess

    Ian Holst🇺🇸 · Dan Hooper🇺🇸

    It has been suggested that the Galactic Center Gamma-Ray Excess (GCE) could be produced by a large number of centrally-located millisecond pulsars. The fact that no such pulsar population has been detected implies that these sources must be very faint and very numerous. In this study, we use the contents of Fermi's recently released Third Pulsar Catalog (3PC) to measure the luminosity function of the millisecond pulsars in the Milky Way's Disk. We find that this source population exhibits a luminosity function with a mean gamma-ray luminosity of $⟨L_{\gamma }⟩\sim 6\times 10^{32}erg/s$ (integrated above 0.1 GeV). If the GCE were generated by millisecond pulsars with the same luminosity function, we find that $\sim 20$ such sources from the Inner Galaxy population should have already been detected by Fermi and included in the 3PC. Given the lack of such observed sources, we exclude the hypothesis that the GCE is generated by pulsars with the same luminosity function as those in the Galactic Disk with a significance of $3.4\sigma$. We conclude that either less than 39\% of the GCE is generated by pulsars, or that the millisecond pulsars in the Inner Galaxy are at least 5 times less luminous on average than those found in the Galactic Disk.

    ↳ astro-ph.HEastro-ph.COastro-ph.GAhep-phPRD(2025)·17 citations
33. 33*

    Bulk-local dS${}_3$ holography: the Matter with $T\bar{T}+{\Lambda }_2$

    Gauri Batra🇺🇸 · G. Bruno De Luca🇺🇸 · Eva Silverstein🇺🇸 · Gonzalo Torroba🇦🇷 · Sungyeon Yang🇺🇸

    We propose an algorithm which builds a concrete dual for large-radius 3d de Sitter with a timelike York boundary for both gravity and bulk effective fields. This generalizes the solvable $T\bar{T}+{\Lambda }_2$ deformation, whose finite real spectrum accounts for the refined Gibbons-Hawking entropy as a microstate count while reproducing the radial static patch geometry. The required generalization to produce approximately local boundary conditions for bulk quantum fields requires a scheme for defining double-trace operators dual to deformed boundary conditions to realize the finite timelike boundary, valid at finite N. By starting with a small stint of a pure $T\bar{T}$ trajectory, the theory becomes finite, enabling well-defined subtractions to define the double-trace deformation so as to match the large-N prescription of Hartman, Kruthoff, Shaghoulian, and Tajdini to good approximation. We incorporate the matter effecting an uplift from negative to positive cosmological constant, and analyze the effect of matter on the energy spectrum of the theory arising from time-dependent bulk excitations. This validates the cosmic horizon $d{S}_3$ microstate count for large-radius $d{S}_3$ holography, embedding $T\bar{T}+{\Lambda }_2$ concretely into a larger theory consistent with bulk locality for matter fields. We comment briefly on potential upgrades to four dimensions and other future directions.

    ↳ hep-thgr-qchep-phJHEP(2024)·48 citations
34. 34*

    Angular analyses of rare decays at the LHC

    Biplab Dey (on behalf of the LHCb collaboration)🇭🇺

    Loop-suppressed penguin $b\to s$ transitions are sensitive to heavy New Physics particles propagating inside the loops. Thanks to the large sample sizes from the LHC, we are able to perform multidimensional angular analyses that are sensitive to interferences between the Standard Model and New Physics terms. This article surveys the latest results, primarily from LHCb, on $b\to s{\mu }^{+}{\mu }^{-}$ electroweak and $b\to s\gamma$ radiative penguins.

    ↳ hep-exhep-phPoS(2024)·0 citations
35. 35*

    Spontaneous chiral symmetry breaking and mass gap of QCD in finite volume

    Xiaolan Meng🇨🇳 · Bolun Hu🇨🇳 · Yi-Bo Yang🇨🇳

    We present the lattice QCD simulation with the 2+1+1 flavor full QCD ensembles using near-physical quark masses and different spatial sizes $L$, at $a\sim$ 0.055 fm. The results suggest that spontaneous chiral symmetry breaking is effectively restored at $L\le 1.0$ fm, while the gap between the nucleon and pion masses remains.

    ↳ hep-lathep-phCommun.Theor.Phys.(2024)·1 citation
36. 36*

    An analytical approximation of the evolution of the primordial curvature perturbation in the ultraslow-roll inflation

    Ji-Xiang Zhao🇨🇳 · Nan Li🇨🇳

    Cosmic inflation can enter an ultraslow-roll (USR) stage, if there is a plateau on the inflaton potential. During this stage, the primordial curvature perturbation ${\mathcal{R}}_k$ and its power spectrum ${\mathcal{P}}_{\mathcal{R}}$ can be remarkably enhanced on small scales. In this work, an analytical approximation is provided to systematically study the evolution of ${\mathcal{R}}_k$ in the USR inflation. We first discuss the asymptotic solutions of the moduli and arguments of ${\mathcal{R}}_k$ and its time derivative ${\mathcal{R}}_{k,N}$ on the sub- and super-horizon scales separately and find that all these solutions have simple exponential forms. Then, ${\mathcal{R}}_k$ on five typical scales are investigated in order. Our analytical approximation predicts that ${\mathcal{R}}_k$ first revolves around the origin in the complex plane, but if it crosses the horizon around the start of the USR stage, there appears a subsequent linear evolution towards or away from the origin. This behavior naturally explains the shape of ${\mathcal{P}}_{\mathcal{R}}$ from the sharp dip to the peak and matches the numerical results perfectly. Moreover, the minimum of ${\mathcal{P}}_{\mathcal{R}}$ is exactly proved to be nonvanishing. Our analytical approximation will help the model building in primordial black hole and gravitational wave physics.

    ↳ astro-ph.COgr-qchep-phEPJC(2024)·4 citations
37. 37*

    Generalized Symmetry in Dynamical Gravity

    Clifford Cheung🇺🇸 · Maria Derda🇺🇸 · Joon-Hwi Kim🇺🇸 · Vinicius Nevoa🇺🇸 · Ira Rothstein🇺🇸 · Nabha Shah🇺🇸

    We explore generalized symmetry in the context of nonlinear dynamical gravity. Our basic strategy is to transcribe known results from Yang-Mills theory directly to gravity via the tetrad formalism, which recasts general relativity as a gauge theory of the local Lorentz group. By analogy, we deduce that gravity exhibits a one-form symmetry implemented by an operator $U_{\alpha }$ labeled by a center element $\alpha$ of the Lorentz group and associated with a certain area measured in Planck units. The corresponding charged line operator $W_{\rho }$ is the holonomy in a spin representation $\rho$, which is the gravitational analog of a Wilson loop. The topological linking of $U_{\alpha }$ and $W_{\rho }$ has an elegant physical interpretation from classical gravitation: the former materializes an exotic chiral cosmic string defect whose quantized conical deficit angle is measured by the latter. We verify this claim explicitly in an AdS-Schwarzschild black hole background. Notably, our conclusions imply that the standard model exhibits a new symmetry of nature at scales below the lightest neutrino mass. More generally, the absence of global symmetries in quantum gravity suggests that the gravitational one-form symmetry is either gauged or explicitly broken. The latter mandates the existence of fermions. Finally, we comment on generalizations to magnetic higher-form or higher-group gravitational symmetries.

    ↳ hep-thgr-qchep-phJHEP(2024)·25 citations
38. 38*

    Observational Constraints on the Dark Energy with a Quadratic Equation of State

    Hossein Moshafi🇮🇷 · Alireza Talebian🇮🇷 · Ebrahim Yusofi🇮🇷 · Eleonora Di Valentino🇬🇧

    In this study, we introduce a novel late-time effective dark energy model characterized by a quadratic equation of state (EoS) and rigorously examine its observational constraints. Initially, we delve into the background dynamics of this model, tracing the evolution of fluctuations in linear order. Our approach involves substituting the conventional cosmological constant with a dynamically effective dark energy fluid. Leveraging a diverse array of observational datasets encompassing the Planck 2018 Cosmic Microwave Background (CMB), Type Ia Supernovae (SNe), Baryon Acoustic Oscillations (BAO), and a prior on the Hubble constant $H_0$ (R21), we constrain the model parameters. We establish the model's consistency by comparing the Hubble parameter as a function of redshift against observational Hubble data (OHD), benchmarking its performance against the Standard $\Lambda$CDM model. Additionally, our investigation delves into studies of the model's dynamical behavior by computing cosmological parameters such as the deceleration parameter, relative Hubble parameter, and the evolution of the Hubble rate. Furthermore, employing Bayesian analysis, we determine the Bayesian Evidence for our proposed model compared to the reference $\Lambda$CDM model. While our analysis unveils the favorable behavior of the model in various observational tests, the well-known cosmological tensions persist when the full dataset combination is explored.

    ↳ astro-ph.COastro-ph.GAgr-qchep-phPhys.Dark Univ.(2024)·17 citations
39. 39*

    Relativistic corrections to energy spectrum of hydrogen due to the full one-photon-exchange interaction

    Zi-Wen Zhang🇨🇳 · Hai-Qing Zhou🇨🇳

    In this work, we present expressions for the full effective potential corresponding to the one-photon exchange interaction within the framework of an effective Schrödinger-like equation, which is derived exactly from the Bethe-Salpeter equation in quantum electrodynamics. The final effective potential is expressed in terms of eight scalar functions. When these eight scalar functions are expanded in terms of velocities order by order, we can return to the non-relativistic effective potential systematically organized by velocities. By retaining the exact momentum dependence in the effective potential, we estimate its corrections to the energy spectrum of hydrogen using a highly precise numerical method. The comparison of the numerical results with those obtained using conventional bound-state perturbative theory is discussed. Our calculations suggest that it is possible to accurately account for all relativistic contributions using this method. It would be interesting to extend these calculations to positronium, muonic hydrogen, and scenarios involving nuclear structure and radiative corrections.

    ↳ nucl-thhep-phphysics.atom-phCPC(2025)·0 citations
40. 40*

    No massive black holes in the Milky Way halo

    P. Mroz🇵🇱 · A. Udalski🇵🇱 · M.K. Szymanski · I. Soszynski · L. Wyrzykowski · P. Pietrukowicz · S. Kozlowski · R. Poleski · J. Skowron · D. Skowron · K. Ulaczyk · M. Gromadzki and 4 other authors

    The gravitational wave detectors have unveiled a population of massive black holes that do not resemble those observed in the Milky Way and whose origin is debated. According to one possible explanation, these black holes may have formed from density fluctuations in the early Universe (primordial black holes), and they should comprise from several to 100% of dark matter to explain the observed black hole merger rates. If such black holes existed in the Milky Way dark matter halo, they would cause long-timescale gravitational microlensing events lasting years. The previous experiments were not sufficiently sensitive to such events. Here we present the results of the search for long-timescale microlensing events among the light curves of nearly 80 million stars located in the Large Magellanic Cloud that were monitored for 20 years by the OGLE survey. We did not find any events with timescales longer than one year, whereas all shorter events detected may be explained by known stellar populations. We find that compact objects in the mass range from $1.8\times 10^{-4}$ to $6.3M_{\odot }$ cannot compose more than 1% of dark matter, and those in the mass range from $1.3\times 10^{-5}$ to $860M_{\odot }$ cannot make up more than 10% of dark matter. Thus, primordial black holes in this mass range cannot simultaneously explain a significant fraction of dark matter and gravitational wave events.

    ↳ astro-ph.GAastro-ph.COgr-qchep-ex+1Nature(2024)·136 citations
41. 41*

    Physical running of couplings in quadratic gravity

    Diego Buccio🇮🇹 · John F. Donoghue🇺🇸 · Gabriel Menezes🇧🇷 · Roberto Percacci🇮🇹

    We argue that the well-known beta functions of quadratic gravity do not correspond to the physical dependence of scattering amplitudes on external momenta, and derive the correct physical beta functions. Asymptotic freedom turns out to be compatible with the absence of tachyons.

    ↳ hep-thgr-qchep-phPRL(2024)·49 citations
42. 42*

    Microlensing optical depth and event rate toward the Large Magellanic Cloud based on 20 years of OGLE observations

    P. Mroz🇵🇱 · A. Udalski🇵🇱 · M.K. Szymanski · M. Kapusta🇵🇱 · I. Soszynski · L. Wyrzykowski · P. Pietrukowicz · S. Kozlowski · R. Poleski · J. Skowron · D. Skowron · K. Ulaczyk and 5 other authors

    Measurements of the microlensing optical depth and event rate toward the Large Magellanic Cloud (LMC) can be used to probe the distribution and mass function of compact objects in the direction toward that galaxy - in the Milky Way disk, the Milky Way dark matter halo, and the LMC itself. The previous measurements, based on small statistical samples of events, found that the optical depth is an order of magnitude smaller than that expected from the entire dark matter halo in the form of compact objects. However, these previous studies were not sensitive to long-duration events with Einstein timescales longer than 2.5-3 yr, which are expected from massive ($10-100M_{\odot }$) and intermediate-mass ($10^2-10^5{M}_{\odot }$) black holes. Such events would have been missed by the previous studies and would not have been taken into account in calculations of the optical depth. Here, we present the analysis of nearly 20-year-long photometric monitoring of 78.7 million stars in the LMC by the Optical Gravitational Lensing Experiment (OGLE) from 2001 through 2020. We describe the observing setup, the construction of the 20-year OGLE dataset, the methods used for searching for microlensing events in the light-curve data, and the calculation of the event detection efficiency. In total, we find 16 microlensing events (thirteen using an automated pipeline and three with manual searches), all of which have timescales shorter than 1 yr. We use a sample of thirteen events to measure the microlensing optical depth toward the LMC $\tau =(0.121\pm 0.037)\times 10^{-7}$ and the event rate $\Gamma =(0.74\pm 0.25)\times 10^{-7}{\mathrm{yr}}^{-1}{\mathrm{star}}^{-1}$. These numbers are consistent with lensing by stars in the Milky Way disk and the LMC itself, and they demonstrate that massive and intermediate-mass black holes cannot comprise a significant fraction of the dark matter.

    ↳ astro-ph.GAastro-ph.COastro-ph.IMgr-qc+1Astrophys.J.Suppl.(2024)·74 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.