Tue·Jan 9, 2024Tuesday·January 9, 2024

1. 01*

   Neutron beta decay and exact conservation of charged weak hadronic vector current in the Standard Model

   Derar Altarawneh🇯🇴 · Roman Höllwieser🇩🇪 · Markus Wellenzohn🇦🇹

   We investigate a reliability of the hypothesis of exact conservation of the charged weak hadronic vector current in the neutron ${\beta }^{-}$-decay with polarized neutron and unpolarized proton and electron. We calculate the contributions of the phenomenological term, responsible for Exact Conservation of the charged weak hadronic Vector Current (or the ECVC effect) in the neutron ${\beta }^{-}$-decay even for different masses of the neutron and proton (see Leitner et al. Phys. Rev. C73, 065502 (2006)), to the correlation coefficients together with a complete set of contributions of scalar and tensor interactions beyond the Standard Model (SM). We argue if total contributions of scalar and tensor interactions beyond the SM (Phys. Rev. D88, 073002 (2013); arXiv: 1212.0332v4 [hep-ph]) will not be able to reconcile the experimental data on the correlation coefficients with the contributions of the ECVC effect, one may conclude that the charged weak hadronic vector current is not conserved in the hadronic transitions of weak processes with different masses of incoming and outgoing hadrons.

   hep-phnucl-thUniverse(2024)·4 citations
2. 02*

   Investigation for $D^{+}\to {\pi }^{+}\nu \bar{\nu }$ decay process within QCDSR approach

   Yu Chen🇨🇳 · Hai-Bing Fu🇨🇳 · Tao Zhong🇨🇳 · Sheng-Bo Wu🇨🇳 · Dong Huang🇨🇳

   In the paper, we investigate the charmed meson rare decay process $D^{+}\to {\pi }^{+}\nu \bar{\nu }$ by using QCD sum rules approach. Firstly, the pion twist-2 and twist-3 distribution amplitude $\xi$-moments $⟨{\xi }_{2;\pi }^n⟩{|}_{\mu }$ up to 10th-order and $⟨{\xi }_{3;\pi }^{(p,\sigma ),n}⟩{|}_{\mu }$ up to fourth-order are calculated by using QCD sum rule under background field theory. After constructing the light-cone harmonic oscillator model for pion twist-2, 3 DAs, we get their behaviors by matching the calculated $\xi$-moments. Then, the $D\to \pi$ transition form factors are calculated by using QCD light-cone sum rules approach. The vector form factor at large recoil region is $f_{+}^{D\to \pi }(0)=0.627_{-0.080}^{+0.120}$. By taking the rapidly $z(q^2,t)$ converging simplified series expansion, we present the TFFs and the corresponding angular coefficients in the whole squared momentum transfer physical region. Furthermore, we display the semileptonic decay process ${\bar{D}}^0\to {\pi }^{+}e{\bar{\nu }}_e$ differential decay widths and branching fraction with $\mathcal{B}({\bar{D}}^0\to {\pi }^{+}e{\bar{\nu }}_e)=0.308_{-0.066}^{+0.155}\times 10^2$. The ${\bar{D}}^0\to {\pi }^{+}e{\bar{\nu }}_e$ differential/total predictions for forward-backward asymmetry, $q^2$-differential flat terms and lepton polarization asymmetry are also given. After considering the non-standard neutrino interactions, the predictions for the $D^{+}\to {\pi }^{+}\nu \bar{\nu }$ branching fraction is $\mathcal{B}(D^{+}\to {\pi }^{+}\nu \bar{\nu })=1.85_{-0.46}^{+0.93}\times 10^{-8}$.

   hep-phCPC(2024)·1 citation
3. 03*

   Thermal effect in hot QCD matter in strong magnetic fields

   Xin-Jian Wen🇨🇳 · Jia Zhang🇨🇳

   The quasiparticle model is improved by the free magnetic contribution to investigated the QCD matter in a strong magnetic field. The temperature-dependent bag function is determined by the thermodynamic consistency to represent the difference in energy density between physical vacuum and lowest state of QCD. It is found that the positive bag function vanishes at high temperature indicating the deconfinement. The rapid decrease of the bag function in stronger magnetic fields reveals the so-called inverse magnetic catalysis. The interaction measure at high temperature remains so large that the usual Stefan-Boltzmann limit can not be reached. We suggest a limit $|q_i{B}_m|T^2/4$ for each landau level pressure. Finally, it is demonstrated that the positive magnetization modified by the bag function and free magnetic contribution indicates the paramagnetic characteristic of QCD matter.

   hep-phPRC(2024)·7 citations
4. 04*

   Probing dark photons from a light scalar at Belle II

   Kingman Cheung🇹🇼 · Yongkyu Kim🇰🇷 · Youngjoon Kwon🇰🇷 · C.J. Ouseph🇹🇼 · Abner Soffer🇮🇱 · Zeren Simon Wang🇹🇼

   In the minimal $U(1)$ extension of the Standard Model (SM), a new gauge boson referred to as "dark photon" is predicted. The dark-photon mass can be generated from an additional Higgs mechanism associated with a dark scalar boson. At $B$-factories such as Belle II, large numbers of $B$-mesons are produced and can decay to a kaon plus the dark scalar via the latter's mixing with the SM Higgs boson. We evaluate the sensitivity of Belle II for the case in which the dark scalar decays exclusively into a pair of dark photons via the new $U(1)$ gauge coupling, and the dark photons are long lived owing to a small kinetic mixing $ϵ$. We study the experimental signature in which each dark photon decays into a pair of charged leptons, pions, or kaons, resulting in a pair of displaced vertices, and argue that the search is essentially background-free. We perform detailed Monte-Carlo simulations to determine the expected number of signal events at Belle II with an integrated luminosity of 50 ab${}^{-1}$, taking into account the efficiencies for both final-state-particle identification and displaced tracking. We find that for experimentally allowed values of the scalar mixing angle and kinematically allowed dark-photon and dark-scalar masses, the proposed search is uniquely sensitive to the medium-$ϵ$ regime, which is currently mostly unexcluded by experiments.

   hep-phhep-exJHEP(2024)·20 citations
5. 05*

   QCD anomalies in electromagnetic processes: A solution to the $\gamma \to 3\pi$ puzzle

   Zanbin Xing🇨🇳 · Hao Dang🇨🇳 · M. Atif Sultan🇨🇳 · Khépani Raya🇪🇸 · Lei Chang🇨🇳

   In this work, the $\gamma \to 3\pi$ form factor is calculated within the Dyson-Schwinger equations framework using a contact interaction model within the so-called modified rainbow ladder truncation. The present calculation takes into account the pseudovector component in the pion Bethe-Salpeter amplitude (BSA) and $\pi -\pi$ scattering effects, producing a $\gamma \to 3\pi$ anomaly which is $1+6{\mathcal{R}}_{\pi }^2$ larger than the low energy prediction. Here ${\mathcal{R}}_{\pi }$ is the relative ratio of the pseudovector and pseudoscalar components in the pion BSA; with our parameters input, this correction raises the $\gamma \to 3\pi$ anomaly by around $10\%$. The main outcome of this work is the unveiling of the origin of such correction, which could be a possible explanation of the discrepancy between the existing experimental data and the low energy prediction. Moreover, it is highlighted how the magnitude of the anomaly is affected in effective theories that require an irremovable ultraviolet cutoff. We find that for both the anomalous processes $\pi \to 2\gamma$ and $\gamma \to 3\pi$, the missing contribution to the anomaly can be compensated by the additional structures related with the quark anomalous magnetic moment.

   hep-phPRD(2024)·9 citations
6. 06*

   Machine-Learning Performance on Higgs-Pair Production Associated with Dark Matter at the LHC

   Ernesto Arganda🇪🇸 · Manuel Epele🇦🇷 · Nicolas I. Mileo🇦🇷 · Roberto A. Morales🇦🇷

   Di-Higgs production at the LHC associated with missing transverse energy is explored in the context of simplified models that generically parameterize a large class of models with heavy scalars and dark matter candidates. Our aim is to figure out the improvement capability of machine-learning tools over traditional cut-based analyses. In particular, boosted decision trees and neural networks are implemented in order to determine the parameter space that can be tested at the LHC demanding four $b$-jets and large missing energy in the final state. We present a performance comparison between both machine-learning algorithms, based on the maximum significance reached, by feeding them with different sets of kinematic features corresponding to the LHC at a center-of-mass energy of 14 TeV. Both algorithms present very similar performances and substantially improve traditional analyses, being sensitive to most of the parameter space considered for a total integrated luminosity of 1 ab${}^{-1}$, with significances at the evidence level, and even at the discovery level, depending on the masses of the new heavy scalars. A more conservative approach with systematic uncertainties on the background of 30\% has also been contemplated, again providing very promising significances.

   hep-phhep-exEur.Phys.J.Plus(2024)·3 citations
7. 07*

   Thin layer axion dynamo

   Maxim Dvornikov (IZMIRAN)🇷🇺

   We study interacting classical magnetic and pseudoscalar fields in frames of the axion electrodynamics. A large scale pseudoscalar field can be the coherent superposition of axions or axion like particles. We consider the evolution of these fields in a thin spherical layer. Decomposing the magnetic field into the poloidal and toroidal components, we take into account their symmetry properties. The dependence of the pseudoscalar field on the latitude is accounted for the induction equation. Then, we derive the dynamo equations in the low mode approximation. The nonlinear evolution equations for the harmonics of the magnetic and pseudoscalar fields are solved numerically. As an application, we consider a dense axion star embedded in solar plasma. The behavior of the harmonics and their typical oscillations frequencies are obtained. We suggest that such small objects consisting of axions and confined magnetic fields can cause the recently observed flashes in solar corona contributing to its heating.

   hep-phastro-ph.SREPJC(2024)·5 citations
8. 08*

   Hidden charmonium decays of spin-2 partner of $X(3872)$

   Yuanxin Zheng🇨🇳 · Zuxin Cai🇨🇳 · Gang Li🇨🇳 · Shidong Liu🇨🇳 · Jiajun Wu🇨🇳 · Qi Wu🇨🇳

   The Belle collaboration recently reported a promising candidate for the spin-2 $D^{\ast }{\bar{D}}^{\ast }$ partner of the $X(3872)$, called the $X_2$ for short, having a mass of $(4014.3\pm 4.0\pm 1.5)\mathrm{MeV}$ and a width of $(4\pm 11\pm 6)\mathrm{MeV}$. Assuming the $X_2$ as a pure molecule of the $D^{\ast }{\bar{D}}^{\ast }$, we calculated in detail the hidden charmonium decays of the $X_2\to J/\psi V$ and $X_2\to {\eta }_{c}P$ via the intermediate meson loops, where $V={\rho }^0,\omega$ and $P={\pi }^0,\eta ,{\eta }^{\prime }$. The results indicate that the decay widths are strongly dependent on the $X_2$ mass. At present center value of the mass $4014.3\mathrm{MeV}$, the width for the $X_2\to J/\psi {\rho }^0$ is predicted to be a few tens of keV, while it is on the order of $10^{2\text{-}3}\mathrm{keV}$ for the $X_2\to J/\psi \omega$; the predicted width for the $X_2\to {\eta }_c{\pi }^0$ is about a few keV, while the widths for $X_2\to {\eta }_c\eta$ and ${\eta }_c{\eta }^{\prime }$ are around a few tens and tenths of keV, respectively. We also investigated the dependence of the ratios between these widths on the $X_2$ mass and on the $\eta$-${\eta }^{\prime }$ mixing angle, which may be good quantities for experiments. We hope that the present calculations would be checked experimentally in the future.

   hep-phPRD(2024)·11 citations
9. 09*

   Charge-breaking domain walls separating neutral vacua in multi-Higgs models

   Yucheng Yang🇨🇳 · Igor P. Ivanov🇨🇳

   The scalar potential of a multi-Higgs model can possess a rich structure of minima and saddle points, which evolves in an intricate way as the parameters change. In the hot early Universe, it could trigger multi-step phase transitions, with exotic intermediate phases and peculiar domain wall configurations. Here, we provide a glimpse into this richness with the example of the three-Higgs-doublet model with the symmetry group $\Sigma (36)$, either exact or softly broken. We present its phase diagram tracking not only the global minimum but all of its extrema. In particular, we reveal parameter space regions in which the deepest saddle point is charge breaking. This naturally leads to phase transitions between neutral vacua which involve expanding and colliding charge-breaking bubble walls. We also comment on opportunities of multi-step phase transitions, on charge-breaking intermediate phases, and on phase transitions between different charge-breaking vacua. We illustrate the general discussion with two benchmark models, one of which possesses competing saddle points and allows for emergence of bubbles of the same true vacuum but with bubble walls of different nature. The intriguing cosmological implications of all these possibilities deserve dedicated study.

   hep-phPRD(2024)·6 citations
10. 10*

    Prospects for testing CPT and Lorentz symmetry with deuterium ground-state Zeeman-hyperfine transitions

    Arnaldo J. Vargas🇺🇸

    This work presents a model for testing Lorentz and CPT symmetry through sidereal-variation studies of the hyperfine-Zeeman deuterium ground-state transition frequencies. It represents an advancement over previous models by using a well-established deuteron wave-function parametrization to calculate contributions from nucleon Lorentz-violating operators toward the Lorentz-violating frequency shift. Furthermore, this work extends the analysis beyond the zeroth-boost order previously considered. This study centers on deuterium's potential for testing Lorentz-violating nonminimal terms. Specifically, it compares the prospects of an ongoing deuterium experiment with the current best limits on nonminimal coefficients. The conclusion drawn is that the deuterium experiment holds the potential to enhance and establish first-time limits on nonminimal proton, neutron, and electron SME coefficients, marking it as a valuable experiment in the current worldwide systematic search for Lorentz and CPT violation.

    hep-phPRD(2024)·7 citations
11. 11*

    Comparison of spectrum models as applied to single-particle ${\mathbf{p}}_{\mathbf{t}}$ spectra from high-energy p-p collisions and their physical interpretations

    Thomas A. Trainor🇺🇸

    A parametrized mathematical model is required to extract the information carried by transverse momentum $p_t$ spectra from high-energy nuclear collisions and subject it to physical interpretation in terms of possible hadron production mechanisms. The importance of proper model construction and implementation has increased with the emergence of claims for ``collectivity'' (flows) associated with small collision systems (e.g. $p$-$p$ and $p$-Pb). A two-element spectrum model, denoted herein as the Bylinkin model, includes an exponential element and a ``power-law'' element interpreted by the authors to represent emission from a thermalized source and from jet production respectively. Application of the Bylinkin model to various collision systems has led to conclusions about achievement of thermalization and other characteristics of nuclear dynamics. In connection with the Bylinkin model there has emerged theoretical conjecture that the thermalization mechanism signaled by the exponential element is hard processes interacting with quantum entanglement within projectile protons. Predating the Bylinkin model is a two-component (soft+hard) model (TCM) derived empirically from the evolution of $p$-$p$ spectrum data with event multiplicity as a form of data compression. The TCM has been applied to many collision systems and hadron species from which a systematic description of high-energy nuclear collisions has emerged. The Bylinkin model can be seen as a limiting case of the TCM model functions that is unsuited to represent underlying production mechanisms. The present study provides detailed comparisons of the two models for a variety of situations and contrasts two very different data interpretations that result.

    hep-ph2 citations
12. 12*

    The general propagator for S-wave threshold states

    Hongge Xu🇨🇳 · Ning Yu🇨🇳 · Zuman Zhang🇨🇳 · Guoying Chen🇨🇳

    We demonstrate that the propagator, derived from an Effective Field Theory (EFT) that incorporates Weinberger's compositeness theorem, provides a more general formula for describing S-wave near-threshold states. By fitting the lineshape using this propagator, we can extract the $Z$ factor for these states and elucidate their structures.

    hep-phhep-exJHEP(2025)·3 citations
13. 13*

    Quark and gluon distributions in $\rho$-meson from basis light-front quantization

    Satvir Kaur🇨🇳 · Jiatong Wu🇨🇳 · Zhi Hu🇯🇵 · Jiangshan Lan🇨🇳 · Chandan Mondal🇨🇳 · Xingbo Zhao🇨🇳 · James P. Vary🇺🇸

    We solve for the $\rho$-meson's wave functions from a light-front QCD Hamiltonian determined for its constituent quark-antiquark and quark-antiquark-gluon Fock components, with a three-dimensional confinement using basis light-front quantization. From this, we obtain the leading-twist valence quark's parton distribution functions and transverse momentum-dependent parton distributions inside the $\rho$-meson. These results are qualitatively consistent with those of other models. We also demonstrate the important effects of a dynamical gluon on the $\rho$-meson's gluon densities, helicity, transversity, and tensor polarized distributions.

    hep-phPLB(2024)·21 citations
14. 14*

    Impact of non-thermal phase-space distributions on dark matter abundance in secluded sectors

    Hugues Beauchesne🇹🇼 · Cheng-Wei Chiang🇹🇼

    Many new physics models include secluded sectors that interact little with the Standard Model and whose internal interactions control the dark matter abundance. If these same interactions are responsible for maintaining kinematic equilibrium within the secluded sector, it is possible that the phase-space distributions will differ considerably from their thermal values during freeze-out. This can potentially result in deviations of the dark matter abundance from that computed under the assumption of thermal distributions. In this paper, we revisit dark matter abundance computations for a benchmark secluded sector by numerically tracking the phase-space distributions. Namely, we show that the dark matter abundance can deviate considerably from standard results during the freeze-out process, but that a longer period of annihilation ultimately leaves only a slight excess.

    hep-phEPJC(2024)·4 citations
15. 15*

    Study of $B\to PP$ decays in the modified perturbative QCD approach

    Sheng Lü🇨🇳 · Ru-Xuan Wang🇨🇳 · Mao-Zhi Yang🇨🇳

    We study the nonleptonic decays of $B\to PP$ in the modified perturbative QCD approach, where $P$ stands for pseudoscalar mesons. Transverse momenta of partons and the Sudakov factor are included, which help to suppress the contributions of soft interactions. The wave function of the $B$ meson obtained from the relativistic potential model is used, and then the contributions in the infrared region can not be suppressed completely. So a soft cutoff scale and soft form factors are introduced. The contributions with the scale higher than the soft cutoff scale are calculated with perturbative QCD, while the contributions lower than the cutoff scale are replaced by the soft form factors. To explain experimental data, we find that contributions of color-octet operators for the quark-antiquarks in the mesons in the final state need to be considered. The contributions of the color-octet operators are parametrized by a few parameters with the help of SU(3) flavor symmetry and symmetry breaking. These parameters for color-octet contributions are universal for all the nonleptonic decay modes of the $B$ meson, where the mesons in the final state belong to the same flavor SU(3) nonet. Both the branching ratios and $CP$ violations are studied. We find that the theoretical calculation can well explain the experimental data of $B$ factories.

    hep-phPRD(2024)·6 citations
16. 16*

    Heavy Hexaquarks in the Flux Tube Model

    Sindhu D G🇮🇳 · Akhilesh Ranjan🇮🇳 · Hemwati Nandan🇮🇳 · V. Sharma🇮🇳

    Hexaquarks are one of the currently emerging topics in both experimental and theoretical high energy physics. Hexaquarks have been examined in relation to particle physics, however, there are still some research and theoretical conjectures surrounding their relationship to dark matter. Due to some experimental discoveries, it has attracted much interest and also resulted in new theoretical models to study the properties of these states. In the present work, Regge trajectories of some hexaquark states are compared with tetraquark and pentaquark states. The study is mainly concentrated on fully heavy hexaquark states. The mass spectra of these hexaquark states have also been investigated and the results are compared with other theoretical works. Our findings agree well with those of other researchers.

    hep-phMod.Phys.Lett.A(2024)·5 citations
17. 17*

    Anomalous diffusion of the heavy quarks through the fractional Langevin equation

    Jai Prakash🇮🇳

    The dynamics of heavy quarks within the hot QCD medium have been revisited, considering the influence of anomalous diffusion. This study has been conducted using the framework of the fractional Langevin equation involving the Caputo fractional derivative. We introduce a numerical scheme for the fractional Langevin equation and demonstrate that the mean square displacement of the particle exhibits anomalous diffusion, deviating from a linear relationship with time. Our analysis calculates various entities, such as mean squared momentum, momentum spread, and the nuclear suppression factor, $R_{AA}$. Notably, our findings indicate that superdiffusion strongly suppresses the $R_{AA}$ compared to normal diffusion in the hot QCD medium. The possible impacts on other parameters are also discussed.

    hep-phnucl-thPRD(2024)·6 citations
18. 18*

    Boosted Dark Matter From Centaurus A and Its Detection

    Chen Xia🇨🇳 · Chuan-Yang Xing🇨🇳 · Yan-Hao Xu🇨🇳

    Dark matter can be boosted by high energy particles in astrophysical environments through elastic scattering. We study the production of boosted dark matter via scattering with electrons in the relativistic jet of the closest active galactic nucleus, Centaurus A, and its detection in the Super-Kamiokande experiment. Since there are a huge number of electrons in the jet and dark matter is extremely dense around the supermassive black hole that powers the jet, the number of boosted dark matter is tremendously large. Compared to boosted dark matter from blazars, the dark matter flux from Centaurus A is enhanced due to the proximity of Centaurus A. The constraint on dark matter-electron scattering cross section set by Super-Kamiokande is more stringent, down to $\sim 10^{-36}{\mathrm{cm}}^2$ for $\mathrm{MeV}$ dark matter.

    hep-phastro-ph.HEJHEP(2024)·15 citations
19. 19*

    Supersymmetry, Part I (Theory)

    Ben Allanach🇬🇧 · Howard E. Haber🇺🇸

    This is a review of the theoretical aspects of the supersymmetric extension of the Standard Model of particle physics, extracted from Chapter 87 of the 2026 Review of Particle Physics, F. Takahashi et al. (Particle Data Group), Int. J. Mod. Phys. A 41, 2630011 (2026). The companion review, co-authored by M. D'Onofrio and F. Moortgat, "Supersymmetry, Part II (Experiment)," can be found in Chapter 88 of the 2026 Review of Particle Physics (op. cit.).

    hep-ph15 citations
20. 20*

    New theoretical developments on the early-time dynamics and approach to equilibrium in Heavy-Ion collisions

    Soeren Schlichting🇩🇪

    We discuss recent theoretical developments in understanding the early pre-equilibrium dynamics and onset of hydrodynamic behavior in high-energy heavy-ion collisions. We highlight possible experimental signatures of the pre-equilibrium phase, and present recent progress in developing a consistent theoretical description of collective flow in small systems.

    hep-phnucl-thEPJ Web Conf.(2024)·6 citations
21. 21*

    Confinement Bubble Wall Velocity via Quasiparticle Determination

    Zhaofeng Kang🇨🇳 · Jiang Zhu🇨🇳

    Lattice simulations reveal that the deconfinement-confinement (D-C) phase transition (PT) of the hot pure $SU(N>2)$ Yang-Mills system is first order. This system can be described by a pool of quasigluons moving in the Polyakov loop background, and in this picture, we establish an effective distribution function for quasigluons, which encodes interactions among quasigluons and in particular the confinement effect. With it, we made the first attempt to calculate the confinement bubble wall velocity $v_w$ at the microscopical level, and we obtained a small velocity $v_w\sim 0.04$ using two different approaches, which is qualitatively consistent with others results like holography.

    hep-phhep-thJHEP(2025)·12 citations
22. 22*

    Mono-Higgs and Mono-$Z$ Production in the Minimal Vector Dark Matter Model

    Gonzalo Benítez-Irarrázabal🇨🇱 · Alfonso R. Zerwekh🇨🇱

    The Minimal Vector Dark Matter is a viable realization of the minimal dark matter paradigm. It extends the Standard Model by the inclusion of a vector matter field in the adjoint representation of $SU(2{)}_L$. The dark matter candidate corresponds to the neutral component of the new vector field ($V^0$). Previous studies have shown that the model can explain the observed dark matter abundance while evading direct and indirect searches. At colliders, the attention has been put on the production of the charged companions of the dark matter candidate. In this work, we focus on the mono-Higgs and mono-$Z$ signals at hadron colliders. The new charged vectors ($V^{\pm }$) are invisible unless a dedicated search is performed. Consequently, we assume that the mono-Higgs and mono-$Z$ processes correspond the $pp\to h{V}^{+,0}{V}^{-,0}$ and $pp\to Z{V}^{+,0}{V}^{-,0}$ reactions, respectively. We show that, while the $pp\to h{V}^{+,0}{V}^{-,0}$ is more important, both channels may produce significant signals at the HL-LHC and colliders running at $\sqrt{s}=27$ TeV and $100$ TeV, probing almost the complete parameter space.

    hep-phUniverse(2024)·2 citations
23. 23*

    MaRTIn -- Manual for the "Massive Recursive Tensor Integration"

    Joachim Brod🇺🇸 · Lorenz Hüdepohl🇩🇪 · Emmanuel Stamou🇩🇪 · Tom Steudtner🇩🇪

    We present MaRTIn, an extendable all-in-one package for calculating amplitudes up to two loops in an expansion in external momenta or using the method of infrared rearrangement. Renormalizable and non-renormalizable models can be supplied by the user; an implementation of the Standard Model is included in the package. In this manual, we discuss the scope and functionality of the software, and give instructions of its use.

    hep-phComput.Phys.Commun.(2025)·16 citations
24. 24*

    Parisi-Wu Quantization, CP violation and Beyond the Standard Model

    A. K. Kapoor🇮🇳

    The Parisi-Wu scheme of quantization opens up the possibility of using anomalous fermionic gauge theories. An analysis of ultra-violet divergences reveals that the structure of counter terms is different from what is expected in conventional quantization schemes. In this letter it is argued that there exists a possible mechanism of CP violation that requires at least three generations of quarks, a result well known from a phenomenological analysis of mass mixing of quarks. A few observations on possible ways of going beyond the standard model are included.

    hep-phhep-thMod.Phys.Lett.A(2024)·0 citations
25. 25*

    QED meson description of the anomalous particles at ~17 and ~38 MeV

    Cheuk-Yin Wong🇺🇸

    The Schwinger confinement mechanism stipulates that a massless fermion and a massless antifermion are confined as a massive boson when they interact in the Abelian QED interaction in (1+1)D. If we approximate light quarks as massless and apply the Schwinger confinement mechanism to quarks, we can infer that a light quark and a light antiquark interacting in the Abelian QED interaction are confined as a QED meson in (1+1)D. Similarly, a light quark and a light antiquark interacting in the QCD interaction in the quasi-Abelian approximation will be confined as a QCD meson in (1+1)D. The QED and QCD mesons in (1+1)D can represent physical mesons in (3+1)D when the flux tube radius is properly taken into account. Such a theory leads to a reasonable description of the masses of ${\pi }^0,\eta$, and ${\eta }^{\prime }$, and its extrapolation to the unknown QED sector yields an isoscalar QED meson at about 17 MeV and an isovector QED meson at about 38 MeV. The observations of the anomalous soft photons, the hypothetical X17 particle, and the hypothetical E38 particle bear promising evidence for the possible existence of the QED mesons. Pending further confirmation, they hold important implications on the properties on the quarks and their interactions.

    hep-phUniverse(2024)·4 citations
26. 26*

    Leading order track functions in a hot and dense QGP

    João Barata🇺🇸 · Robert Szafron🇺🇸

    We study the modifications to the fragmentation pattern of partons into charged particles in the presence of a hot and dense Quark Gluon Plasma. To this end, we analyze the perturbative renormalization group equations of the track functions, which describe the energy fraction carried by charged hadrons. Focusing on pure Yang-Mills theory, we compute the lowest order moments of the medium-modified track functions, which are found to be sensitive to the reduced phase space for emissions in the medium and to energy loss. We use the extracted moments to calculate the Energy Energy Correlator (EEC) on tracks in the collinear limit. The EEC on medium-evolved tracks does not differ qualitatively from the EEC on vacuum tracks despite being sensitive to the color decoherence transition and suppressing the distribution due to quenching, as seen in other jet observables.

    hep-phhep-exnucl-thPRD(2024)·16 citations
27. 27*

    The impact of asymmetric dark matter on the thermal evolution of nucleonic and hyperonic compact stars

    Edoardo Giangrandi🇵🇹 · Afonso Ávila🇵🇹 · Violetta Sagun🇵🇹 · Oleksii Ivanytskyi🇵🇱 · Constança Providência🇵🇹

    We investigate the impact of asymmetric fermionic dark matter (DM) on the thermal evolution of neutron stars (NSs), considering a scenario where DM interacts with baryonic matter (BM) through gravity. Employing the two-fluid formalism, our analysis reveals that DM accrued within the NS core exerts an inward gravitational pull on the outer layers composed of BM. This gravitational interaction results in a noticeable increase in baryonic density within the core of the NS. Consequently, it strongly affects the star's thermal evolution by triggering an early onset of the direct Urca (DU) processes, causing an enhanced neutrino emission and rapid star cooling. Moreover, the photon emission from the star's surface is modified due to a reduction of radius. We demonstrate the effect of DM gravitational pull on nucleonic and hyperonic DU processes that become kinematically allowed even for NSs of low mass. We then discuss the significance of observing NSs at various distances from the Galactic center. Given that the DM distribution peaks toward the Galactic center, NSs within this central region are expected to harbor higher fractions of DM, potentially leading to distinct cooling behaviors.

    ↳ astro-ph.HEhep-phParticles(2024)·23 citations
28. 28*

    A New Way to Compute the Pseudoscalar Screening Mass at Finite Chemical Potential

    Prasad Hegde🇮🇳 · Rishabh Thakkar🇨🇳

    We present a method to calculate the pion screening mass in 2+1-flavor lattice QCD to $\mathcal{O}({\mu }_{\ell }^2)$, where ${\mu }_{\ell }$ is the isoscalar chemical potential. Our approach is based on the expression for the free theory pion screening correlator for massless quarks. We use the Taylor expansion method to calculate the screening correlator to $\mathcal{O}({\mu }_{\ell }^4)$. We then extract the $\mathcal{O}({\mu }_{\ell }^2)$ Taylor coefficient of the screening mass from the Taylor coefficients of the correlator, for two temperatures in the range 2 - 3 GeV. Our calculations were done using the Highly Improved Staggered Quark action, and the strange and light quark masses were set respectively to their physical and nearly physical values, corresponding to meson masses $M_{\bar{s}s}=686$ MeV and $M_{\pi }=160$ MeV.

    ↳ hep-lathep-phPoS(2024)·0 citations
29. 29*

    Nontensorial gravitational wave polarizations from the tensorial degrees of freedom: I. Linearized Lorentz-violating theory of gravity with s tensor

    Shaoqi Hou🇨🇳 · Xi-Long Fan🇨🇳 · Tao Zhu🇨🇳 · Zong-Hong Zhu🇨🇳

    General relativity predicts the existence of only two tensorial gravitational wave polarizations, while a generic metric theories of gravity can possess up to four additional polarizations, including two vector and two scalar ones. These vector/scalar polarizations are in general generated by the intrinsic new vector/scalar degrees of freedom of the specific theories of gravity. In this paper, we show that, with the violation of the Lorentz symmetry in the framework of the standard model extension, the additional nontensorial polarizations can be directly excited by the two tensorial degrees of freedom. We consider the diffeomorphism invariant standard model extension in the gravity sector with the Lorentz-violating coefficients ${\hat{\mathbf{s}}}^{(d)\mu \rho \nu \sigma }$ of the even mass dimension $d\ge 4$. In addition to the extra polarizations induced by the tensor modes, the gravitational wave in this theory travels at a speed depending on the propagation direction, experiences dispersion if and only if $d\ge 6$, and possesses neither velocity nor amplitude birefringence. The excitement of the extra polarizations is also chiral. The antenna pattern functions of interferometers due to such kind of gravitational waves are generally linear combinations of those for all polarizations. Detected by pulsar timing arrays and the Gaia satellite, the stochastic gravitational wave background in this model could induce couplings among cross correlations, of the redshifts of photons and the astrometric deflections of the positions of pulsars, for different polarizations. These characteristics enable the use of interferometers, pulsar timing arrays and Gaia mission to constrain this model.

    ↳ gr-qchep-phPRD(2024)·17 citations
30. 30*

    Sub-GeV Dark Matter Annihilation: Limits from Milky Way observations with INTEGRAL

    Thomas Siegert🇩🇪 · Francesca Calore🇫🇷 · Pasquale Dario Serpico🇫🇷

    From 16 years of INTEGRAL/SPI $\gamma$-ray observations, we derive bounds on annihilating light dark matter particles in the halo of the Milky Way up to masses of about 300 MeV. We test four different spatial templates for the dark matter halo, including a Navarro-Frenk-White (NFW), Einasto, Burkert, and isothermal sphere profile, as well as three different models for the underlying diffuse Inverse Compton emission. We find that the bounds on the s-wave velocity-averaged annihilation cross sections for both the electron-positron and the photon-photon final states are the strongest to date from $\gamma$-ray observations alone in the mass range $\lesssim 6$ MeV. We provide fitting formulae for the upper limits and discuss their dependences on the halo profile. The bounds on the two-photon final state are superseding the limits from the Cosmic Microwave Background in the range of 50 keV up to $\sim 3$ MeV, showing the great potential future MeV mission will have in probing light dark matter.

    ↳ astro-ph.HEastro-ph.GAhep-phMNRAS(2024)·18 citations
31. 31*

    Split of the pseudo-critical temperatures of chiral and confine/deconfine transitions by temperature gradient

    Ji-Chong Yang🇨🇳 · Wen-Wen Li🇨🇳 · Chong-Xing Yue🇨🇳

    Searching of the critical endpoint of the phase transition of Quantum Chromodynamics~(QCD) matter in experiments is of great interest. The temperature in the fireball of a collider is location dependent, however, most theoretical studies address the scenario of uniform temperature. In this work, the effect of temperature gradients is investigated using lattice QCD approach. We find that the temperature gradient catalyzes chiral symmetry breaking, meanwhile the temperature gradient increases the Polyakov loop in the confined phase but suppresses the Polyakov loop in the deconfined phase. Furthermore, the temperature gradient decreases the pseudo-critical temperature of chiral transition but increases the pseudo-critical temperature of the confine/deconfine transition.

    ↳ hep-lathep-phnucl-thPRD(2024)·2 citations
32. 32*

    Hadronic contribution to the running of the electromagnetic coupling constant from lattice QCD: challenges at short distances

    Sophie Mutzel🇫🇷

    The electromagnetic coupling constant, $\alpha$, is one of the fundamental parameters of the Standard Model (SM). Its value at the Z boson mass, $\alpha (M_Z)$, is of particular interest as it enters electroweak precision tests. When running $\alpha$ from low energies up to the Z mass, five orders of magnitude in precision are lost. This makes it one of the least well determined parameters of the SM at that scale. The largest source of error comes from non-perturbative hadronic effects in the low energy region. These non-perturbative effects can be determined from ab-initio calculations in lattice QCD. At higher energies, needed to match onto QCD perturbation theory, discretization errors become large. In addition, the hadronic vacuum polarization receives logarithmically-enhanced cutoff effects which render the continuum extrapolation more difficult. To better control this extrapolation at higher energies, we test a number of improvement procedures based on lattice perturbation theory. To illustrate their effect, we present a preliminary analysis of the light quark, connected contribution to the Adler function at Euclidean $Q^2=5$ GeV${}^2$. The lattice results are obtained using simulations with $2+1+1$ flavors of staggered fermions at physical values of the quark masses.

    ↳ hep-lathep-phPoS(2023)·1 citation
33. 33*

    String Theory and the First Half of the Universe

    Fien Apers🇬🇧 · Joseph P. Conlon🇬🇧 · Edmund J. Copeland🇬🇧 · Martin Mosny🇬🇧 · Filippo Revello🇳🇱

    We perform a detailed study of stringy moduli-driven cosmologies between the end of inflation and the commencement of the Hot Big Bang, including both the background and cosmological perturbations: a period that can cover half the lifetime of the universe on a logarithmic scale. Compared to the standard cosmology, stringy cosmologies motivate extended kination, tracker and moduli-dominated epochs involving significantly trans-Planckian field excursions. Conventional effective field theory is unable to control Planck-suppressed operators and so such epochs require a stringy completion for a consistent analysis. Perturbation growth in these stringy cosmologies is substantially enhanced compared to conventional cosmological histories. The transPlanckian field evolution results in radical changes to Standard Model couplings during this history and we outline potential applications to baryogenesis, dark matter and gravitational wave production.

    ↳ hep-thastro-ph.COhep-phJCAP(2024)·55 citations
34. 34*

    Generalized form factors of the pion and kaon using twisted mass fermions

    Joseph Delmar🇺🇸 · Constantia Alexandrou🇨🇾 · Simone Bacchio🇨🇾 · Ian Cloët🇺🇸 · Martha Constantinou🇺🇸 · Giannis Koutsou🇨🇾

    We present an update on our lattice calculations of the Mellin moments of PDFs and GPDs for the pion and kaon, using momentum-boosted meson states. In particular, we focus on the calculation of the scalar and tensor local operators, and the vector operator with up to three-covariant derivatives. The corresponding matrix elements allow us to extract the scalar and tensor charges, as well as $⟨x^n⟩$ with $n=1,2,3$. In addition, we introduce momentum transfer between the initial and final meson state that leads to the scalar, vector, and tensor form factors, and the generalized form factors up to three covariant derivatives. The above results are obtained using two ensembles of maximally twisted mass fermions with clover improvement with two degenerate light, a strange, and a charm quark $(N_f=2+1+1)$ at lattice spacings of 0.093 fm and 0.081 fm. The pion mass of the ensembles is about 260 MeV. We study excited-states effects by analyzing four values of the source-sink time separation (1.12 - 1.67 fm). We also examine discretization and volume effects. The lattice data are renormalized non-perturbatively, and the results are presented in the MS scheme at a scale of 2 GeV.

    ↳ hep-lathep-phPoS(2024)·9 citations
35. 35*

    Stringy Spacetime Uncertainty Principle and a Modified Trans-Planckian Censorship Criterion

    Robert Brandenberger🇨🇦 · Pei-Ming Ho🇹🇼 · Hikaru Kawai🇹🇼 · Wei-Hsiang Shao🇹🇼

    We study the implications of the stringy space-time uncertainty relation (STUR) for inflationary cosmology. By demanding that no fluctuation modes that exit the Hubble radius are affected by the nonlocality resulting from the STUR, we find an upper bound on the number of e-foldings of inflation. The bound is a factor of 2 weaker than what results from the Trans-Planckian Censorship Criterion (TCC). By demanding that the inflationary phase is simultaneously consistent with STUR and sufficiently long for inflation to provide a causal explanation of structure on the scale of the current Hubble radius, we find an upper bound on the energy scale of inflation. The bound is less restrictive than what follows from the TCC, but it remains in conflict with canonical single-field inflation models.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2024)·5 citations
36. 36*

    Optimal, fast, and robust inference of reionization-era cosmology with the 21cmPIE-INN

    Benedikt Schosser🇩🇪 · Caroline Heneka🇩🇪 · Tilman Plehn🇩🇪

    Modern machine learning will allow for simulation-based inference from reionization-era 21cm observations at the Square Kilometre Array. Our framework combines a convolutional summary network and a conditional invertible network through a physics-inspired latent representation. It allows for an efficient and extremely fast determination of the posteriors of astrophysical and cosmological parameters, jointly with well-calibrated and on average unbiased summaries. The sensitivity to non-Gaussian information makes our method a promising alternative to the established power spectra.

    ↳ astro-ph.COastro-ph.GAastro-ph.IMhep-phSciPost Phys.Core(2025)·22 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.