Tue·Nov 29, 2022Tuesday·November 29, 2022

1. 01*

   Establishing the Range of Applicability of Hydrodynamics in High-Energy Collisions

   Victor E. Ambrus🇷🇴 · S. Schlichting🇩🇪 · C. Werthmann🇩🇪

   We simulate the space-time dynamics of high-energy collisions based on a microscopic kinetic description in the conformal relaxation time approximation, in order to determine the range of applicability of an effective description in relativistic viscous hydrodynamics. We find that hydrodynamics provides a quantitatively accurate description of collective flow when the average inverse Reynolds number is sufficiently small and the early pre-equilibrium stage is properly accounted for. We further discuss the implications of our findings for the (in)applicability of hydrodynamics in proton-proton, proton-nucleus and light nucleus collisions.

   hep-phnucl-thPRL(2023)·54 citations
2. 02*

   Opacity dependence of transverse flow, pre-equilibrium and applicability of hydrodynamics in heavy-ion collisions

   Victor E. Ambrus🇷🇴 · S. Schlichting🇩🇪 · C. Werthmann🇩🇪

   We evaluate the full opacity dependence of collective flow in high-energy heavy-ion collisions within a microscopic kinetic description based on the Boltzmann equation in the conformal relaxation time approximation. By comparing kinetic theory calculations to hydrodynamic and hybrid simulations for an average initial state, we point out shortcomings and inaccuracies of hydrodynamic models and present modified simulation setups to improve them.

   hep-phnucl-thPRD(2023)·36 citations
3. 03*

   Role of the $\rho (1450)$ in low-energy observables from an analysis in the meson dominance approach

   Gustavo Ávalos🇲🇽 · Antonio Rojas🇲🇽 · Marxil Sánchez🇲🇽 · Genaro Toledo🇲🇽

   The $\rho (1450)$ vector meson (${\rho }^{\prime }$) is becoming increasingly important to properly describe precision observables. We analyse a set of decay modes and cross sections, in the low-energy regime, to determine the role played by this meson. This is done through the extraction of the parameters for its description, in the context of the vector meson dominance model and its effective hadronic interactions, involving the low mass lying hadrons ($\rho$, $\omega$ and $\pi$). In a first step, we determine the parameters of the model from ten decay modes which are insensitive to the ${\rho }^{\prime }$. Then, we consider the $\omega \to 3\pi$ decay and exhibit the need to extend the description, by incorporating the ${\rho }^{\prime }$ and a contact term as prescribed by the Wess-Zumino-Witten anomaly. In a second step, we incorporate the data from the $e^{+}{e}^{-}\to 3\pi$ cross section (as measured by SND, CMD2, BABAR and BESIII) and then the $e^{+}{e}^{-}\to {\pi }^0{\pi }^0\gamma$ data (as measured by SND and CDM2) to further restrict the ${\rho }^{\prime }$ parameters validity region. As an application of the results, we compute the $e^{+}{e}^{-}\to 4\pi$ cross section for the so-called omega channel, measured by BABAR, and find a good description of the data considering the parameters found. As a byproduct, the coupling between $\rho$, $\omega$ and $\pi$ ($g_{\rho \omega \pi }=11.314\pm 0.383$ GeV${}^{-1}$) is found to be consistent with all the relevant observables, upon the inclusion of the ${\rho }^{\prime }$ and the contact term.

   hep-phPRD(2023)·6 citations
4. 04*

   Box enhanced Charged Lepton Flavor Violation in the Grimus-Neufeld model

   Vytautas Dūdėnas🇱🇹 · Thomas Gajdosik🇱🇹 · Uladzimir Khasianevich🇩🇪 · Wojciech Kotlarski🇵🇱 · Dominik Stöckinger🇩🇪

   In the Grimus-Neufeld model (GNM) the neutrino mass generation from an extended Higgs sector leads to bounds from Charged Lepton Flavour Violating (cLFV) processes. Here we update bounds from the previous study by extending the parameter space to nonvanishing Majorana phase of the Pontecorvo-Maki-Nakagawa-Sakata matrix and to heavier charged Higgs boson masses. Three-body cLFV decays are shown to contribute significantly in large mass regions, as the boxes are enhanced relatively to photonic diagrams. This is in contrast to the smaller mass region studied before, in which the two-body decays tightly restrict the parameter space. The Majorana phase is shown to change limits within one order of magnitude. The tiny seesaw scale is assumed, which makes the cLFV decays of the GNM to be similar to the scotogenic model and the scoto-seesaw models.

   hep-phPRD(2023)·4 citations
5. 05*

   Improved Factorization for Threshold Resummation in Heavy Quark to Heavy Quark Decays

   U.G. Aglietti🇮🇹 · G. Ferrera🇮🇹

   We consider the resummation of soft-gluon effects in heavy quark to heavy quark decays, namely the processes Q1 -> Q2 + (non QCD partons), where Q1 and Q2 are two different heavy quarks. We construct a new factorization scheme for threshold resummed spectra, which allows us to consistently evaluate the distribution of the final hadron invariant mass mX in all the kinematic regions, i.e. when mX is smaller, of the same order, or larger than the mass of the final quark Q2. A dependence of the Improved Coefficient Function on the threshold variable is introduced, which can however be relegated to a small interval of this variable by means of the so-called Partition of Unity. We explicitly apply our improved scheme to the b -> X_s + gamma decay at next-to-leading logarithmic accuracy.

   hep-phEPJC(2023)·13 citations
6. 06*

   Effective Chiral Magnetic Effect from Neutrino Radiation

   Naoki Yamamoto🇯🇵 · Di-Lun Yang🇹🇼

   We develop an approach to chiral kinetic theories for electrons close to equilibrium and neutrinos away from equilibrium based on a systematic power counting scheme for different timescales of electromagnetic and weak interactions. Under this framework, we derive electric and energy currents along magnetic fields induced by neutrino radiation in general nonequilibrium states. This may be regarded as an effective chiral magnetic effect (CME), which is present without a chiral chemical potential, unlike the conventional CME. We also consider the so-called gain region of core-collapse supernovae as an example and find that the effective CME enhanced by persistent neutrino emission in time is sufficiently large to lead to the inverse cascade of magnetic and fluid kinetic energies and observed magnitudes of pulsar kicks. Our framework may also be applicable to other dense-matter systems involving nonequilibrium neutrinos.

   hep-phastro-ph.HEnucl-thPRL(2023)·8 citations
7. 07*

   QCD spectral sum rules 2022

   Stephan Narison🇫🇷

   We present a compact review of the status of QCD spectral sum rules until 2022. We emphasize the recent progresses for determining the QCD input parameters (${\alpha }_s$, running quark masses, quark and gluon condensates) where their correlations have been taken into account. Some selected phenomenological uses of the sum rules in different channels (light and heavy quarks, gluonia/glueballs, hybrids and four-quark states) are briefly reviewed and commented. The estimate of the $1^{-+}$ light hybrid mass is revised which confirms the hybrid nature of the ${\pi }_1(1600)$ but not the ${\pi }_1(2050)$.

   hep-phhep-exhep-latNucl.Part.Phys.Proc.(2023)·11 citations
8. 08*

   Helicity amplitudes in light-cone and Feynman-diagram gauges

   Junmou Chen🇨🇳 · Kaoru Hagiwara🇯🇵 · Junichi Kanzaki🇯🇵 · Kentarou Mawatari🇯🇵 · Ya-Juan Zheng🇯🇵

   Recently proposed Feynman-diagram (FD) gauge propagator for massless and massive gauge bosons is obtained from a light-cone (LC) gauge propagator, by choosing the gauge vector along the opposite direction of the gauge boson three-momentum. We implement a general LC gauge propagator for all the gauge bosons of the Standard Model (SM) in the HELicity Amplitude Subroutines (HELAS) codes, such that all the SM helicity amplitudes can be evaluated at the tree level in the LC gauge by using MadGraph. We confirm that our numerical codes produce physical helicity amplitudes which are consistent among all gauge choices. We then study interference patterns among Feynman amplitudes, for a few $2\to 3$ scattering processes in QED and QCD, and the process $\gamma \gamma \to W^{+}{W}^{-}$ followed by the $W^{\pm }$ decays. We find that in a generic LC gauge, where all the gauge boson propagators share a common gauge vector, we cannot remove the off-shell current components which grow with their energy systematically from all the Feynman amplitudes in $2\to 3$ processes. On the other hand, the $5\times 5$ LC gauge propagator for the weak bosons removes components which grow with energy due to the longitudinal polarization mode of the external bi-fermion currents, and hence can give $2\to 2$ weak boson scattering amplitudes which are free from subtle cancellation at high energies. The particular choice of the FD gauge vector has advantages over generic LC gauge, not only because all the terms which grow with energy of off-shell and on-shell currents are removed systematically from all the diagrams, but also because no artificial gauge vector direction dependence of individual amplitudes appears.

   hep-phEur.Phys.J.Plus(2024)·11 citations
9. 09*

   Light higgsino scenario confronted with muon g-2

   Jun Zhao🇨🇳 · Jingya Zhu🇨🇳 · Pengxuan Zhu🇨🇳 · Rui Zhu🇨🇳

   Light higgsinos below several hundred GeV are favored or required by the naturalness of low energy supersymmetry. If only higgsinos are light while other sparticles are sufficiently heavy, we have the so-called light higgsino scenario. Confronted with the muon $g-2$ data, this scenario is examined in this work. Since in this scenario the LSP (lightest sparticle) is higgsino-like, we need to also consider the dark matter constraints. Assuming a light higgsino mass parameter $\mu$ in the range of 100-400 GeV while gaugino mass parameters above TeV, we explore the parameter space under the muon $g-2$ data and the dark matter constraints. We find that, to explain the muon $g-2$ anomaly at $2\sigma$, the winos and sleptons are respectively upper bounded by 3 TeV and 800 GeV. In this case, we find that the light higgsino-like dark matter can sizably scatter with nucleon and thus the allowed parameter space can be covered almost fully by the future LZ dark matter detection project. We also perform a Monte Carlo simulation to figure out the potential of HL-LHC to detect the light sleptons in this scenario. It turns out that compared with the current LHC limits, the HL-LHC can further cover a part of the parameter space.

   hep-phPRD(2023)·16 citations
10. 10*

    Ruling out light axions: the writing is on the wall

    Konstantin A. Beyer🇬🇧 · Subir Sarkar🇬🇧

    We revisit the domain wall problem for QCD axion models with more than one quark charged under the Peccei-Quinn symmetry. Symmetry breaking during or after inflation results in the formation of a domain wall network which would cause cosmic catastrophe if it comes to dominate the Universe. The network may be made unstable by invoking a `tilt' in the axion potential due to Planck scale suppressed non-renormalisable operators. Alternatively the random walk of the axion field during inflation can generate a `bias' favouring one of the degenerate vacua, but we find that this mechanism is in practice irrelevant. Consideration of the axion abundance generated by the decay of the wall network then requires the Peccei-Quinn scale to be rather low -- thus ruling out e.g. the DFSZ axion with mass below 11 meV, where most experimental searches are in fact focussed.

    hep-phastro-ph.COSciPost Phys.(2023)·46 citations
11. 11*

    Quantum field theory and the structure of the Standard Model

    José Ignacio Illana🇪🇸 · Alejandro Jiménez Cano🇪🇸

    The Standard Model of the electroweak and strong interactions of particle physics is a quantum field theory. Elementary particles are not indivisible `pieces' of matter but energy bundles of fields, whose properties and interactions are a consequence of the principles of symmetry. These lecture notes provide a brief introduction to the construction of the Standard Model from its basic ingredients: Poincaré symmetry, gauge invariance and spontaneous symmetry breaking. The full Lagrangian is derived in detail and the most relevant aspects of the electroweak phenomenology are discussed with special emphasis on the determination of the input parameters and the consistency checks of the model. Some exercises are proposed to fix the main ideas.

    hep-phPoS(2022)·9 citations
12. 12*

    Holographic energy loss near critical temperature in an anisotropic background

    Qi Zhou🇨🇳 · Ben-Wei Zhang🇨🇳

    We study the energy loss of a quark moving in a strongly coupled QGP under the influence of anisotropy. The heavy quark drag force, diffusion coefficient, and jet quenching parameter are calculated using the Einstein-Maxwell-dilaton model, where the anisotropic background is characterized by an arbitrary dynamical parameter $A$.Our findings indicate that as the anisotropic factor $A$ increases, the drag force and jet quenching parameter both increase, while the diffusion coefficient decreases. Additionally, we observe that the energy loss becomes more significant when the quark moves perpendicular to the anisotropy direction in the transverse plane.The enhancement of the rescaled jet quenching parameters near critical temperature $T_c$, as well as drag forces for a fast-moving heavy quark is observed, which presents one of the typical features of QCD phase transition.

    hep-phCommun.Theor.Phys.(2023)·8 citations
13. 13*

    Effect of hadronic cascade time on freeze-out properties of Identified Hadrons in Au+Au Collisions at $\sqrt{s_{NN}}$ = 7.7-39 GeV from AMPT Model

    M. U. Ashraf🇧🇪 · Junaid Tariq🇵🇰 · A. M. Khan🇨🇳

    We report the transverse momentum $p_T$ spectra of identified hadrons (${\pi }^{\pm }$, $K^{\pm }$ and $p(\bar{p})$) in Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7 - 39 GeV from A Multi Phase Transport Model with string melting effect (AMPT-SM). During this study, a new set of parameters are explored to study the effect of hadronic cascade by varying hadronic cascade time $t_{max}$ = 30 $f$m/$c$ and 0.4 $f$m/$c$. No significant effect of this change is observed in the $p_T$ spectra of light hadrons and the AMPT-SM model reasonably reproduces the experimental data. To investigate the kinetic freeze-out properties the blast wave fit is performed to the $p_T$ spectra and it is found that the blast wave model describes the AMPT-SM simulations well. We additionally observe that the kinetic freeze-out temperature ($T_{kin}$) increases from central to peripheral collisions, which is consistent with the argument of short-lived fireball in peripheral collisions. Whereas the transverse flow velocity, $<{\beta }_T>$ shows a decreasing trend from central to peripheral collisions indicating a more rapid expansion in the central collisions. Both, $T_{kin}$ and $<{\beta }_T>$ show a weak dependence on the collision energy at most energies. We also observe a strong anti-correlation between $T_{kin}$ and $<{\beta }_T>$. The extracted freeze-out parameters from the AMPT-SM simulations agree with the experimental data as opposed to earlier studies that reported some discrepancies. Whereas, no significant effect is found on the freeze-out parameters by varying the $t_{max}$. We also report the $p_T$ spectra of light hadrons and their freeze-out parameters by AMPT-SM simulations at $\sqrt{s_{NN}}$ = 14.5 GeV, where no experimental data is available for comparison. Overall, the set of parameters used in this study well describes the experimental data at BES energies.

    hep-ph1 citation
14. 14*

    Molecular Interpretation of $X(3960)$ as $D_s^{+}{D}_s^{-}$ State

    Halil Mutuk🇹🇷

    We study $D_s^{+}{D}_s^{-}$ and $D\bar{D}$ states assuming that they are hadronic molecules with $J^{PC}=0^{++}$ quantum number. We use two-point QCD sum rule formalism and extract the mass and decay constant values of these states. We take into account contributions of various quark, gluon, and mixed vacuum condensates up to dimension eight. The extracted mass and decay constant values of $D\bar{D}$ and $D_s^{+}{D}_s^{-}$ states read as $M_{D\bar{D}}=3795_{-82}^{+85}\mathrm{MeV}$, $f_{D\bar{D}}=1.70_{-0.29}^{+0.33}\times 10^{-2}{\mathrm{GeV}}^5$, and $M_{D_s^{+}{D}_s^{-}}=3983_{-88}^{+93}\mathrm{MeV}$, $f_{D_s^{+}{D}_s^{-}}=2.52_{-0.54}^{+0.64}\times 10^{-2}{\mathrm{GeV}}^5$, respectively. The predicted mass of $D_s^{+}{D}_s^{-}$ state is in good agreement with the recent LHCb observation and supports quantum number and molecular picture assignments. A possible observation of $D\bar{D}$ state would help for establishing the lowest four-quark state in charmonium sector.

    hep-phhep-exhep-latEPJC(2022)·35 citations
15. 15*

    Overview of IR-Improvement in Precision LHC/FCC Physics

    S. A. Yost🇺🇸 · Y. Liu🇺🇸 · B. Shakerin🇺🇸 · B. F. L. Ward🇺🇸

    We present an overview of the use of IR-improvement of unintegrable singularities in the infrared regime via amplitude-based resummation in $\mathrm{QED}\times \mathrm{QCD}$ $\subset$ $\mathrm{SU}(2{)}_L\times {\mathrm{U}}_1\times \mathrm{SU}(3{)}^c$. We work in the context of precision LHC/FCC physics. While illustrating such IR-improvement in specific examples, we discuss new results and new issues.

    hep-phPoS(2022)·0 citations
16. 16*

    The fully-light vector tetraquark states with explicit P-wave via the QCD sum rules

    Qi Xin🇨🇳 · Zhi-Gang Wang🇨🇳

    In this paper, we apply the QCD sum rules to study the vector fully-light tetraquark states with an explicit P-wave between the diquark and antidiquark pair. We observed that the $C{\gamma }_{\alpha }\otimes {\overleftrightarrow{\partial }}_{\mu }\otimes {\gamma }^{\alpha }C$ (or $C{\gamma }_{\alpha }\otimes {\overleftrightarrow{D}}_{\mu }\otimes {\gamma }^{\alpha }C$) type current with fully-strange quarks couples potentially to a tetraquark state with the mass $2.16\pm 0.14\mathrm{GeV}$, which supports assigning the $Y/\varphi (2175)$ as the diquark-antidiquark type tetraquark state with the $J^{PC}=1^{--}$. The $qs\bar{q}\bar{s}$ and $ss\bar{s}\bar{s}$ vector tetraquark states with the structure $C{\gamma }_{\mu }\otimes {\overleftrightarrow{\partial }}_{\alpha }\otimes {\gamma }^{\alpha }C+C{\gamma }^{\alpha }\otimes {\overleftrightarrow{\partial }}_{\alpha }\otimes {\gamma }_{\mu }$ (or $C{\gamma }_{\mu }\otimes {\overleftrightarrow{D}}_{\alpha }\otimes {\gamma }^{\alpha }C+C{\gamma }^{\alpha }\otimes {\overleftrightarrow{D}}_{\alpha }\otimes {\gamma }_{\mu }$) are consistent with the $X(2200)$ and $X(2400)$ respectively, which lie in the region $2.20$ to $2.40\mathrm{GeV}$. The central values of the masses of the fully-strange vector tetraquark states with an explicit P-wave are about $2.16-3.13\mathrm{GeV}$ (or $2.16-3.16\mathrm{GeV}$), and the predictions for other fully-light vector tetraquark states with and without hidden-strange are also presented.

    hep-phCPC(2024)·12 citations
17. 17*

    Nature of $X(3872)$ in $B^0\to K^{0}X(3872)$ and $B^{+}\to K^{+}X(3872)$ decays

    Hao-Nan Wang🇨🇳 · Li-Sheng Geng🇨🇳 · Qian Wang🇨🇳 · Ju-Jun Xie🇨🇳

    We investigate the decays of $B^0\to K^{0}X(3872)$ and $B^{+}\to K^{+}X(3872)$ based on the picture where the $X(3872)$ resonance is strongly coupled to the $D{\bar{D}}^{\ast }+c.c.$ channel. In addition to the decay mechanism where the $X(3872)$ resonance is formed from the $c\bar{c}$ pair hadronization with the short-distance interaction, we have also considered the $D{\bar{D}}^{\ast }$ rescattering diagrams in the long-distance scale, where $D$ and ${\bar{D}}^{\ast }$ are formed from $c$ and $\bar{c}$ separately. Because of the difference of the mass thresholds of charged and neutral $D{\bar{D}}^{\ast }$ channels, and the rather narrow width of the $X(3872)$ resonance, at the $X(3872)$ mass, the loop functions of $D^0{\bar{D}}^{\ast 0}$ and $D^{+}{\bar{D}}^{\ast -}$ are much different. Taking this difference into account, the ratio of $\mathcal{B}[B^0\to K^{0}X(3872)]/\mathcal{B}[B^{+}\to K^{+}X(3872)]\simeq 0.5$ can be naturally obtained. Based on this result, we also evaluate the decay widths of $B_s^0\to \eta ({\eta }^{\prime })X(3872)$. It is expected that future experimental measurements of these decays can be used to elucidate the nature of the $X(3872)$ resonance.

    hep-phhep-exnucl-exnucl-thChin.Phys.Lett.(2023)·14 citations
18. 18*

    Doubly heavy tetraquark multiplets as heavy antiquark-diquark symmetry partners of heavy baryons

    Tian-Wei Wu🇨🇳 · Yong-Liang Ma🇨🇳

    Symmetries play important roles in the understanding of hadron structures and spectroscopy. Motivated by the discovery of the doubly charmed tetraquark $T_{cc}^{+}(3875)$, we study the ground states of the doubly heavy tetraquarks with the QCD inspired heavy antiquark-diquark symmetry in the constituent quark model. Six ground states of $T_{QQ}(Q=c,b)$ are predicted and the lightest $T_{cc}$ state has a mass of $3875.8\pm 7.6$ MeV and spin-parity $1^{+}$ which are consistent with those of the observed $T_{cc}^{+}(3875)$. In addition, the magnetic moments of the predicted tetraquarks $T_{cc}^{+}(3876)$ and $T_{bb}^{-}(10396)$ are also estimated in the same model, which provide further informations to distinguish the structures of the $T_{QQ}$ states. Our results show that the heavy antiquark-diquark symmetry conserves well in these doubly heavy tetraquarks in both the spectrum and magnetic moment perspectives.

    hep-phPRD(2023)·34 citations
19. 19*

    Chiral perturbative analysis for an almost massless neutrino in the type-I seesaw mechanism

    Masaki J. S. Yang🇯🇵

    In this paper, we perform chiral perturbative analysis of an approximate lepton number symmetry associated with a sufficiently light neutrino in the type-I seesaw mechanism. For the Dirac mass matrix $m_D=(\mathbf{A},\mathbf{B},\mathbf{C})$, linearly independent components of $\mathbf{C}$ from $\mathbf{A}$ and $\mathbf{B}$ are treated as symmetry-breaking parameters. A deviation in the eigenvector of the massless mode $\delta \mathbf{u}$ occurs in the first-order perturbation and the lightest mass $m_{1\mathrm{or}3}\propto \det m_D^2/M_3$ emerges in the second-order. By solving the perturbation theory, we obtained specific expressions of $\delta \mathbf{u}$ and $m_{1\mathrm{or}3}$. As a result, two complex parameters in $m_D$ are bounded to some extent from the eigenvector. These constraints are associated with the chiral symmetry and are not susceptible to renormalization.

    hep-phNPB(2023)·3 citations
20. 20*

    Mass spectra of bottom-charm baryons

    Zhen-Yu Li🇨🇳 · Guo-Liang Yu🇨🇳 · Zhi-Gang Wang🇨🇳 · Jian-Zhong Gu🇨🇳 · Hong-Tao Shen🇨🇳

    In this paper, we investigate the mass spectra of bottom-charm baryons systematically, where the relativistic quark model and the infinitesimally shifted Gaussian basis function method are employed. Our calculation shows that the $\rho$-mode appears lower in energy than the other excited modes. According to this feature, the allowed quantum states are selected and a systematic study of the mass spectra for ${\Xi }_{bc}^{{}^{\prime }}$ (${\Xi }_{bc}$) and ${\Omega }_{bc}^{{}^{\prime }}$ (${\Omega }_{bc}$) families is performed. The root mean square radii and quark radial probability density distributions of these baryons are analyzed as well. Next, the Regge trajectories in the $(J,M^2)$ plane are successfully constructed based on the mass spectra. At last, we present the structures of the mass spectra, and analyze the difficulty and opportunity in searching for the ground states of bottom-charm baryons in experiment.

    hep-phInt.J.Mod.Phys.A(2023)·15 citations
21. 21*

    One-loop formulas for $H\to Z{\nu }_l{\bar{\nu }}_l$ for $l=e,\mu ,\tau$ in 't Hooft-Veltman gauge

    Dzung Tri Tran🇻🇳 · Khiem Hong Phan (DTU)🇻🇳

    In this paper, we present analytical results for one-loop contributing to the decay processes $H\to Z{\nu }_l{\bar{\nu }}_l$ (for $l=e,\mu ,\tau$). The calculations are performed within the Standard Model framework in 't Hooft-Veltman gauge. One-loop form factors are then written in terms of scalar one-loop functions in the standard notations of {\tt LoopTools}. As a result, one-loop decay rates for the decay channels can be evaluated numerically by using the package. Furthermore, we analyse the signals of $H\to Z{\nu }_l{\bar{\nu }}_l$ via the production processes $e^{-}{e}^{+}\to Z{H}^{\ast }\to Z(H^{\ast }\to Z{\nu }_l{\bar{\nu }}_l)$ including the initial beam polarizations at future lepton collider. The Standard Model background such as the processes $e^{-}{e}^{+}\to {\nu }_l{\bar{\nu }}_{l}ZZ$ are also examined in this study. In numerical results, we find that one-loop corrections are about $10\%$ contributions to the decay rates. They are sizeable contributions and should be taken into account at future colliders. We show that the signals $H\to Z{\nu }_l{\bar{\nu }}_l$ are clearly visible at center-of-mass energy $\sqrt{s}=250$ GeV and it is hard to probe at higher-energy regions due to the dominant of the background.

    hep-phCPC(2023)·5 citations
22. 22*

    The DM approach to semileptonic heavy-to-heavy and heavy-to-light $B$ decays

    G. Martinelli🇮🇹 · M. Naviglio🇮🇹 · S. Simula🇮🇹 · L. Vittorio🇫🇷

    We present the results of the application of the Dispersion Matrix approach to semileptonic heavy-to-heavy and heavy-to-light $B$-meson decays. This method allows to determine the hadronic form factors in a non-perturbative and model-independent way. Starting from the available lattice results at large values of the momentum transfer, we obtain the behaviour of the form factors in their whole kinematical range without introducing any parameterization of their momentum dependence. We will focus on the determination of the Cabibbo-Kobayashi-Maskawa matrix elements $|V_{cb}|$ and $|V_{ub}|$ through the analysis of $B\to D^{(\ast )}\ell \nu$, $B_s\to D_s^{(\ast )}\ell \nu$, $B\to \pi \ell \nu$ and $B_s\to K\ell \nu$ decays. New theoretical determinations of the Lepton Flavour Universality ratios relevant for these transitions will be also presented, by focusing in particular on the $R(D_{(s)}^{(\ast )})$ ratios.

    hep-phhep-exhep-latPoS(2023)·2 citations
23. 23*

    LHC sensitivity to Z'/W' states in composite Higgs models

    J. Fiaschi🇬🇧 · F. Giuli🇨🇭 · F. Hautmann🇨🇭 · S. Moretti🇬🇧

    Using the 4-Dimensional Composite Higgs Model (4DCHM) realization of the minimal composite Higgs scenario, we discuss the Large Hadron Collider (LHC) sensitivity to new physics signals from multiple $Z^{\prime }$ and $W^{\prime }$ broad resonances. We illustrate the role of systematic uncertainties due to QCD effects encoded in parton distribution functions for experimental searches in leptonic channels. We show that, by reducing this systematics through the combination of high-precision measurements of Standard Model (SM) lepton-charge and forward-backward asymmetries near the SM vector-boson peak, the sensitivity to the new physics signals can be greatly enhanced.

    hep-phPoS·0 citations
24. 24*

    $O({\alpha }_s^2$) Polarized Heavy Flavor Corrections}to Deep-Inelastic Scattering at $Q^2\gg m^2$

    I. Bierenbaum🇩🇪 · J.Blümlein🇩🇪 · A. De Freitas🇩🇪 · A. Goedicke🇩🇪 · S. Klein🇺🇸 · K. Schönwald🇨🇭

    We calculate the quarkonic $O({\alpha }_s^2)$ massive operator matrix elements $\Delta A_{Qg}(N),\Delta A_{Qq}^{\mathrm{PS}}(N)$ and $\Delta A_{qq,Q}^{\mathrm{NS}}(N)$ for the twist--2 operators and the associated heavy flavor Wilson coefficients in polarized deeply inelastic scattering in the region $Q^2\gg m^2$ to $O(\epsilon )$ in the case of the inclusive heavy flavor contributions. The evaluation is performed in Mellin space, without applying the integration-by-parts method. The result is given in terms of harmonic sums. This leads to a significant compactification of the operator matrix elements and massive Wilson coefficients in the region $Q^2\gg m^2$ derived previously in \cite{BUZA2}, which we partly confirm, and also partly correct. The results allow to determine the heavy flavor Wilson coefficients for $g_1(x,Q^2)$ to $O({\alpha }_s^2)$ for all but the power suppressed terms $\propto (m^2/Q^2{)}^k,k\ge 1$. The results in momentum fraction $z$-space are also presented. We also discuss the small $x$ effects in the polarized case. Numerical results are presented. We also compute the gluonic matching coefficients in the two--mass variable flavor number scheme to $O(\epsilon )$.

    hep-phhep-exNPB(2023)·36 citations
25. 25*

    AMY Lorentz invariant parton cascade -- the thermal equilibrium case

    Aleksi Kurkela🇳🇴 · Robin Törnkvist🇸🇪 · Korinna Zapp🇸🇪

    We introduce ALPACA, a Lorentz invariant parton cascade encoding the AMY effective kinetic theory of QCD at high temperatures. It solves the Boltzmann equation by explicitly simulating the evolution of parton ensembles corresponding to single events. We discuss how the effective masses and temperature entering the elastic collision and splitting/merging rates can be estimated from just a single event. We perform an extensive validation of the framework by showing that it reproduces the expected behaviour in thermal equilibrium.

    hep-phnucl-thEPJC(2024)·15 citations
26. 26*

    Calculation of one-loop integrals for four-photon amplitudes by functional reduction method

    O. V. Tarasov🇷🇺

    The method for functional reduction of Feynman integrals, proposed by the author, is used to calculate one-loop integrals corresponding to diagrams with four external lines. The integrals that emerge from amplitudes for the scattering of light by light, the photon splitting in an external field and Delbrück scattering are considered. For master integrals in $d$ - dimensions, new analytic results are presented. For $d=4$, these integrals are given by compact expressions in terms of logarithms and dilogarithms.

    hep-phhep-thPhys.Part.Nucl.Lett.(2023)·5 citations
27. 27*

    Quenching jets increases their flavor

    Chathuranga Sirimanna🇺🇸 · Ismail Soudi🇺🇸 · Gojko Vujanovic🇺🇸 · Wen-Jing Xing🇨🇳 · Shanshan Cao🇨🇳 · Abhijit Majumder🇺🇸

    The widespread notion that jets quenched in a Quark-Gluon-Plasma (QGP) are similar in their parton flavor composition to jets in vacuum is critically examined. We demonstrate that while the soft to semi-hard [low to intermediate transverse momentum ($p_T$)] sector of vacuum jets are predominantly bosonic i.e., composed of gluons, \emph{sufficiently} quenched jets can have an intermediate momentum sector that is predominantly fermionic, dominated by quarks and antiquarks. We demonstrate, using leading order perturbative QCD processes, that the rate of flavor conversion from a gluon traversing the QGP as part of a jet, to a quark or antiquark, versus the reverse process, grows steadily with falling $p_T$. Simple diagrammatic estimates are followed by a variety of realistic simulations in static media. The relation of this increase in flavor to the observed baryon enhancement at intermediate $p_T$ is studied in a fully realistic simulation.

    hep-phnucl-exnucl-thPRC(2023)·14 citations
28. 28*

    Interplay among gravitational waves, dark matter and collider signals in the singlet scalar extended type-II seesaw model

    Purusottam Ghosh🇮🇳 · Tathagata Ghosh🇮🇳 · Subhojit Roy🇮🇳

    We study the prospect of simultaneous explanation of tiny neutrino masses, dark matter (DM), and the observed baryon asymmetry of the Universe in a $Z_3$-symmetric complex singlet scalar extended type-II seesaw model. The complex singlet scalar plays the role of DM. Analyzing the thermal history of the model, we identify the region of the parameter space that can generate a first-order electroweak phase transition (FOEWPT) in the early Universe, and the resulting stochastic gravitational waves (GW) can be detected at future space/ground-based GW experiments. First, we find that light triplet scalars do favor an FOEWPT. In our study, we choose the type-II seesaw part of the parameter space in such a way that light triplet scalars, especially the doubly charged ones, evade the strong bounds from their canonical searches at the Large Hadron Collider (LHC). However, the relevant part of the parameter space, where FOEWPT can happen only due to strong SM doublet-triplet interactions, is in tension with the SM-like Higgs decay to a pair of photons, which has already excluded the bulk of this parameter space. On the other hand, the latest spin-independent DM direct detection constraints from XENON-1T and PANDA-4T eliminate a significant amount of parameter space relevant for the dark sector assisted FOEWPT scenarios, and it is only possible when the complex scalar DM is significantly underabundant. In short, we conclude from our analysis that the absence of new physics at the HL-LHC and/or various DM experiments in the near future will severely limit the prospects of detecting a stochastic GW at future GW experiments and will exclude the possibility of electroweak baryogenesis within this model.

    hep-phJHEP(2023)·38 citations
29. 29*

    Dark gauge boson emission from supernova pions

    Chang Sub Shin🇰🇷 · Seokhoon Yun🇮🇹

    The hot, neutron-rich, and dense circumstance in core-collapse supernovae provides a source of negatively charged pions that may make up a significant portion of the matter. These abundant thermal pions can play a role to populate light and hidden hypothetical particles. We discuss the dark gauge boson production via reactions involving supernova pions, the rate of which is determined by the isovector nucleon coupling. We take into account the two toy models, the dark photon and the gauged $B-L$ models, that carry the typical distinct isovector nucleon coupling structure in the medium. Pion-induced dark gauge bosons leave an imprint on several observational consequences associated with supernova. Their sizable emissivity and characteristic hard spectral distribution result in the stringent constraints on the dark gauge boson models, in particular at masses above the two electron mass.

    hep-phastro-ph.HEPRD(2023)·23 citations
30. 30*

    Neutrino Non-standard Interactions with arbitrary couplings to u and d quarks

    Nicolás Bernal🇦🇪 · Yasaman Farzan🇮🇷

    We introduce a model for Non-Standard neutral current Interaction (NSI) between neutrinos and the matter fields, with an arbitrary coupling to the up and down quarks. The model is based on a new $U(1)$ gauge symmetry with a light gauge boson that mixes with the photon. We show that the couplings to the $u$ and $d$ quarks can have a ratio such that the contribution from NSI to the Coherent Elastic Neutrino-Nucleus Scattering (CE$\nu$NS) amplitude vanishes, relaxing the bound on the NSI from the CE$\nu$NS experiments. Additionally, the deviation of the measured value of the anomalous magnetic dipole moment of the muon from the standard-model prediction can be fitted. The most limiting constraints on our model come from the search for the decay of the new gauge boson to $e^{-}{e}^{+}$ and invisible particles, carried out by NA48/2 and NA64, respectively. We show that these bounds can be relaxed by opening up the decay of the new gauge boson to new light scalars that eventually decay into the $e^{-}{e}^{+}$ pairs. We show that there are ranges that can lead to both a solution to the $(g-2{)}_{\mu }$ anomaly and values of ${ϵ}_{\mu \mu }={ϵ}_{\tau \tau }$ large enough to be probed by future solar neutrino experiments.

    hep-phPRD(2023)·11 citations
31. 31*

    Relaxion Dark Matter from Stochastic Misalignment

    Aleksandr Chatrchyan🇩🇪 · Géraldine Servant🇩🇪

    Cosmological relaxation of the electroweak scale via Higgs-axion interplay, named as relaxion mechanism, provides a dynamical solution to the Higgs mass hierarchy. In the original proposal by Graham, Kaplan and Rajendran, the relaxion abundance today is too small to explain the dark matter of the universe because of the high suppression of the misalignment angle after inflation. It was then realised by Banerjee, Kim and Perez that reheating effects can displace the relaxion, thus enabling it to account for the dark matter abundance from the misalignment mechanism. However, this scenario is realised in a limited region of parameter space to avoid runaway. We show that in the regime where inflationary fluctuations dominate over the classical slow-roll, the "stochastic misalignment" of the field due to fluctuations can be large. We study the evolution of the relaxion after inflation, including the high-temperature scenario, in which the barriers of the potential shrink and destabilise temporarily the local minimum. We open new regions of parameter space where the relaxion can naturally explain the observed dark matter density in the universe, towards larger coupling, larger mass, larger mixing angle, smaller decay constant, as well as larger scale of inflation.

    hep-phastro-ph.COJCAP(2023)·22 citations
32. 32*

    Revisiting the Universal Texture Zero of Flavour: a Markov Chain Monte Carlo Analysis

    Jordan Bernigaud🇩🇪 · Ivo de Medeiros Varzielas🇵🇹 · Miguel Levy🇵🇹 · Jim Talbert🇬🇧

    We revisit the phenomenological predictions of the Universal Texture Zero (UTZ) model of flavour originally presented in arXiv:1710.01741, and update them in light of both improved experimental constraints and numerical analysis techniques. In particular, we have developed an in-house Markov Chain Monte Carlo (MCMC) algorithm to exhaustively explore the UTZ's viable parameter space, considering both leading- and next-to-leading contributions in the model's effective operator product expansion. We also extract -- for the first time -- reliable UTZ predictions for the (poorly constrained) leptonic CP-violating phases, and ratio observables that characterize neutrino masses probed by (e.g.) oscillation, $\beta$-decay, and cosmological processes. We therefore dramatically improve on the proof-in-principle phenomenological analysis originally presented in arXiv:1710.01741, and ultimately show that the UTZ remains a minimal, viable, and appealing theory of flavour. Our results also further demonstrate the potential of robustly examining multi-parameter flavour models with MCMC routines.

    hep-phEPJC(2023)·5 citations
33. 33*

    A new realisation of light thermal self-interacting dark matter and detection prospects

    Debasish Borah🇮🇳 · Satyabrata Mahapatra🇮🇳 · Narendra Sahu🇮🇳

    Light dark matter (DM) in the GeV ballpark faces weaker constraint from direct detection experiments. If such DM also has sufficient self-interactions due to a light mediator, it can alleviate the small-scale problems of the cold dark matter (CDM) paradigm while being consistent with the latter at large scales, as suggested by astrophysical observations. However, generating correct thermal relic for such light DM is challenging. While GeV scale CDM typically leads to thermal overproduction due to the absence of sufficient annihilation channels, self-interacting dark matter (SIDM) typically has under-abundant thermal relic due to its large annihilation rates into mediator particles. In this letter, we propose a minimal realisation of GeV scale SIDM with correct thermal relic, where one of the three singlet fermions, responsible for seesaw origin of light neutrino masses, assists in generating correct SIDM relic density via freeze-out. The setup thereby encompasses astrophysical as well as cosmological aspects of light DM while simultaneously providing a solution to the origin of light neutrino mass. Due to such connection to several frontiers, there exist exciting discovery prospects in terms of direct and indirect search of DM, laboratory and cosmology based dark photon signatures and effective light neutrino mass.

    hep-phastro-ph.COPRD(2023)·12 citations
34. 34*

    On the flavor/mass dichotomy for mixed neutrinos: a phenomenologically motivated analysis based on lepton charge conservation in neutron decay

    Giuseppe Gaetano Luciano🇪🇸

    Flavor/mass dichotomy} for mixed fields is one of the most controversial issues in Quantum Field Theory. In this work we approach the problem by considering mixing of neutrinos and computing the transition amplitude for the paradigmatic neutron $\beta$-decay n\,\rightarrow\, p \,+\,e^ \,+\,\bar\nu. Calculations are developed by utilizing the following different representations of neutrino states: \emph{i}) Pontecorvo states, \emph{ii}) mass states and \emph{iii}) exact QFT flavor states, which are defined as eigenstates of the flavor charge. As a guiding principle, we invoke the conservation of lepton charge in the interaction vertex, which is fundamentally inbuilt into the Standard Model at tree level. In the short-time limit, we show that the only fully consistent scenario is that based on QFT states, whereas the other two frameworks contradict the underlying theory. This result provides a crucial step towards understanding the rôle of neutrino mixing in weak decays and contributes to elucidate the flavor/mass controversy in QFT.

    hep-phEur.Phys.J.Plus(2023)·10 citations
35. 35*

    The Hubble Constant Troubled by Dark Matter in Non-Standard Cosmologies

    Jailson S. Alcaniz🇧🇷 · Jacinto P. Neto🇧🇷 · Farinaldo S. Queiroz🇧🇷 · Deivid R. da Silva🇧🇷 · Raimindo Silva🇧🇷

    The Standard Cosmological Model has experienced tremendous success at reproducing observational data by assuming a universe dominated by a cosmological constant and dark matter in a flat geometry. However, several studies, based on local measurements, indicate that the universe is expanding too fast, in disagreement with the Cosmic Microwave Background. Taking into account combined data from CMB, Baryon Acoustic Oscillation, and type Ia Supernovae, we show that if the mechanism behind the production of dark matter particles has at least a small non-thermal origin, one can induce larger values of the Hubble rate $H_0$, within the $\Lambda$CDM, to alleviate the trouble with $H_0$. In the presence of non-standard cosmology, however, we can fully reconcile CMB and local measurements and reach $H_0=70-74\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$.

    ↳ astro-ph.COastro-ph.HEhep-phhep-thSci.Rep.(2022)·14 citations
36. 36*

    Grover's Quantum Search Algorithm of Causal Multiloop Feynman Integrals

    Andrés E. Rentería-Olivo🇪🇸

    A proof-of-concept application of a quantum algorithm to multiloop Feynman integrals in the Loop-Tree Duality (LTD) framework is applied to a representative four-loop topology. Bootstrapping causality in the LTD formalism, is a suitable problem to address with quantum computers given the straightforward possibility to encode the two on-shell states of a propagator on the two states of a qubit. A modification of Grover's quantum search algorithm is developed and the quantum algorithm is successfully implemented on IBM Quantum and QUTE simulators.

    ↳ quant-phhep-phhep-thPoS·1 citation
37. 37*

    Quarkyonic or baryquark matter? On the dynamical generation of momentum space shell structure

    Volker Koch🇺🇸 · Volodymyr Vovchenko🇺🇸

    We study the equation of state of a mixture of (quasi-)free constituent quarks and nucleons with hard-core repulsion at zero temperature. Two opposite scenarios for the realization of the Pauli exclusion principle are considered: (i) a Fermi sea of quarks surrounded by a shell of baryons -- the quarkyonic matter, and (ii) a Fermi sea of nucleons surrounded by a shell of quarks which we call \emph{baryquark matter}. In both scenarios, the sizes of the Fermi sea and shell are fixed through energy minimization at fixed baryon number density. While both cases yield a qualitatively similar transition from hadronic to quark matter, we find that baryquark matter is energetically favored in this setup and yields a physically acceptable behavior of the speed of sound without the need to introduce an infrared regulator. In order to retain the theoretically more appealing quarkyonic matter as the preferred form of dense QCD matter will thus require modifications to the existing dynamical generation mechanisms, such as, for example, the introduction of momentum-dependent nuclear interactions.

    ↳ nucl-thhep-phPLB(2023)·17 citations
38. 38*

    The on-shell expansion: from Landau equations to the Newton polytope

    Einan Gardi🇬🇧 · Franz Herzog🇬🇧 · Stephen Jones🇬🇧 · Yao Ma🇬🇧 · Johannes Schlenk🇨🇭

    We study the application of the method of regions to Feynman integrals with massless propagators contributing to off-shell Green's functions in Minkowski spacetime (with non-exceptional momenta) around vanishing external masses, $p_i^2\to 0$. This on-shell expansion allows us to identify all infrared-sensitive regions at any power, in terms of infrared subgraphs in which a subset of the propagators become collinear to external lightlike momenta and others become soft. We show that each such region can be viewed as a solution to the Landau equations, or equivalently, as a facet in the Newton polytope constructed from the Symanzik graph polynomials. This identification allows us to study the properties of the graph polynomials associated with infrared regions, as well as to construct a graph-finding algorithm for the on-shell expansion, which identifies all regions using exclusively graph-theoretical conditions. We also use the results to investigate the analytic structure of integrals associated with regions in which every connected soft subgraph connects to just two jets. For such regions we prove that multiple on-shell expansions commute. This applies in particular to all regions in Sudakov form-factor diagrams as well as in any planar diagram.

    ↳ hep-thhep-phJHEP(2023)·55 citations
39. 39*

    A model-free procedure to correct for volume fluctuations in E-by-E analyses of particle multiplicities

    Anar Rustamov🇩🇪 · Joachim Stroth🇩🇪 · Romain Holzmann🇩🇪

    We develop an innovative and unbiased procedure, based on event mixing, to account for unavoidable contributions from volume (or system size) fluctuations to experimentally measured moments of particle multiplicity distributions produced in relativistic nuclear collisions. Within the wounded-nucleon model they are characterized by fluctuations of the number of wounded nucleons, the latter usually referred to as participants. For the first time we extract participant fluctuations directly from the data used for the fluctuation analysis, i.e., without involving model calculations. To achieve this we constructed a dedicated event-mixing algorithm that eliminates all possible correlations between produced particles while preserving the volume fluctuations. The procedure provides direct access to the cumulants of wounded-nucleon distributions, which can be used to account for non-critical contributions to the experimentally measured cumulants of multiplicity distributions.

    ↳ nucl-thhep-phnucl-exNPA(2023)·17 citations
40. 40*

    Probing Fractional Quantum Hall Sheets in Dense Baryonic Matter

    Mannque Rho🇫🇷

    Unlike the octet baryons for $N_f=3$, there is no skyrmion coming from the ${\eta }^{\prime }$ meson. It is instead described as a fractional quantum Hall droplet, a pancake or a pita involving a singular ${\eta }^{\prime }$ ring in which Chern-Simons fields live. By incorporating hidden local symmetry and hidden scale symmetry in nuclear dynamics, I describe how to access baryon-charged quantum Hall droplets in dense nuclear matter in terms of the nuclear scale-chiral effective field theory approach ``G$n$EFT" with the $U_A(1)$ anomaly taken into account. I discuss how the single-flavor baryon that I will call ${\mathcal{B}}^s$ could be exposed in superdense baryonic matter, figuring, perhaps, in ``quark stars" associated with the baryon-quark continuity involving CFL or phase transitions.

    ↳ nucl-thhep-ph5 citations
41. 41*

    Constraining Single-Field Inflation with MegaMapper

    Giovanni Cabass🇺🇸 · Mikhail M. Ivanov🇺🇸 · Oliver H. E. Philcox🇺🇸 · Marko Simonovic🇨🇭 · Matias Zaldarriaga🇺🇸

    We forecast the constraints on single-field inflation from the bispectrum of future high-redshift surveys such as MegaMapper. Considering non-local primordial non-Gaussianity (NLPNG), we find that current methods will yield constraints of order $\sigma (f_{\mathrm{NL}}^{\mathrm{eq}})\approx 23$, $\sigma (f_{\mathrm{NL}}^{\mathrm{orth}})\approx 12$ in a joint power-spectrum and bispectrum analysis, varying both nuisance parameters and cosmology, including a conservative range of scales. Fixing cosmological parameters and quadratic bias parameter relations, the limits tighten significantly to $\sigma (f_{\mathrm{NL}}^{\mathrm{eq}})\approx 17$, $\sigma (f_{\mathrm{NL}}^{\mathrm{orth}})\approx 8$. These compare favorably with the forecasted bounds from CMB-S4: $\sigma (f_{\mathrm{NL}}^{\mathrm{eq}})\approx 21$, $\sigma (f_{\mathrm{NL}}^{\mathrm{orth}})\approx 9$, with a combined constraint of $\sigma (f_{\mathrm{NL}}^{\mathrm{eq}})\approx 14$, $\sigma (f_{\mathrm{NL}}^{\mathrm{orth}})\approx 7$; this weakens only slightly if one instead combines with data from the Simons Observatory. We additionally perform a range of Fisher analyses for the error, forecasting the dependence on nuisance parameter marginalization, scale cuts, and survey strategy. Lack of knowledge of bias and counterterm parameters is found to significantly limit the information content; this could be ameliorated by tight simulation-based priors on the nuisance parameters. The error-bars decrease significantly as the number of observed galaxies and survey depth is increased: as expected, deep dense surveys are the most constraining, though it will be difficult to reach $\sigma (f_{\mathrm{NL}})\approx 1$ with current methods. The NLPNG constraints will tighten further with improved theoretical models (incorporating higher-loop corrections and improved understanding of nuisance parameters), as well as the inclusion of additional higher-order statistics.

    ↳ astro-ph.COgr-qchep-exhep-ph+1PLB(2023)·62 citations
42. 42*

    Near-inflection point inflation and production of dark matter during reheating

    Anish Ghoshal🇵🇱 · Gaetano Lambiase🇮🇹 · Supratik Pal🇮🇳 · Arnab Paul🇮🇳 · Shiladitya Porey🇷🇺

    We study slow roll single field inflationary scenario and the production of non-thermal fermionic dark matter, together with standard model Higgs, during reheating. For the inflationary scenario, we have considered two models of polynomial potential - one is symmetric about the origin and another one is not. We fix the coefficients of the potential from the current Cosmic Microwave Background (CMB) data from Planck/Bicep. Next, we explore the allowed parameter space on the coupling $(y_{\chi })$ with inflaton and mass $(m_{\chi })$ of dark matter (DM) particles $(\chi )$ produced during reheating and satisfying CMB and several other cosmological constraints.

    ↳ astro-ph.COhep-ph5 citations
43. 43*

    High energy nucleus-nucleus collision and halo radii in different approaches of Glauber theory

    Yu.M. Shabelski🇷🇺 · A.G. Shuvaev🇷🇺

    The complete Glauber calculation of the differential cross sections of ${}^{12}$C--${}^{12}$C and halo nuclei on ${}^{12}$C scattering was performed using the previously proposed in Refs.~\cite{Shabelski:2021iqk, Shabelski:2022xkw} method of generating function. The results are different as compared with the similar calculations in the optical model and the rigid target approximation. The halo nuclei radii extracted from the scattering data via the complete Glauber analysis come out to be larger than those obtained in the approximate approaches

    ↳ nucl-thhep-phMod.Phys.Lett.A(2022)·1 citation
44. 44*

    STE-QUEST -- Space Time Explorer and QUantum Equivalence principle Space Test: The 2022 medium-class mission concept

    Naceur Gaaloul · Holger Ahlers · Leonardo Badurina · Angelo Bassi · Baptiste Battelier · Quentin Beaufils · Kai Bongs · Philippe Bouyer · Claus Braxmaier · Oliver Buchmueller · Matteo Carlesso · Eric Charron and 36 other authors

    Space-borne quantum technologies, particularly those based on atom interferometry, are heralding a new era of strategic and robust space exploration. The unique conditions of space, characterized by low noise and low gravity environments, open up diverse possibilities for applications ranging from precise time and frequency transfer to Earth Observation and the search of new Physics. In this paper, we summarise the M-class mission proposal in response to the 2022 call in ESA's science program: Space-Time Explorer and Quantum Equivalence Principle Space Test (STE-QUEST). It consists in a satellite mission featuring a dual-species atom interferometer operating over extended durations. This mission aims to tackle three of the most fundamental questions in Physics: (i) testing the universality of free fall with an accuracy better than one part in $10^{-17}$, (ii) exploring various forms of Ultra-Light Dark Matter, and (iii) scrutinizing the foundations of Quantum Mechanics.

    ↳ physics.space-phgr-qchep-exhep-ph+144 citations
45. 45*

    Gluon helicity distribution in the nucleon from lattice QCD and machine learning

    Tanjib Khan🇧🇩 · Tianbo Liu🇨🇳 · Raza Sabbir Sufian🇺🇸

    We present the first lattice QCD determination of the light cone gluon helicity correlation parton distribution function (PDF) with numerical evidence toward disfavoring negative gluon polarization in the nucleon. We present a solution for eliminating an inevitable contamination term that dominates the Euclidean correlations and makes determining gluon helicity PDF unfeasible. The proposed synergy between lattice QCD and artificial intelligence offers a superior platform to alleviate the defining challenge of extracting quark and gluon PDFs from the lattice data that are available in a limited domain due to a finite range of accessible hadron momenta. We suggest a systematically improvable method to extract PDFs from the lattice data, independent of inadequate parametrizations. The result of the gluon helicity will improve our understanding of the role of spin in the strong interaction and the nucleon spin structure.

    ↳ hep-lathep-phnucl-thPRD(2023)·34 citations
46. 46*

    Explorations in the Space of S-Matrices

    Parthiv Haldar🇮🇳

    S-matrix is one of the fundamental observables of the quantum theory of relativistic particles. There have been attempts to understand the quantum dynamics of relativistic particles abstractly in terms of S-matrix bypassing a Lagrangian formulation of quantum field theory. Equivalently, the space of possible S-matrices defines an abstract theory space. This thesis examines how to constrain the spectrum of physical theories in the theory space using the basic physical requirements of Poincare invariance, quantum unitarity, and causality. The thesis discusses two distinct but related ways of such exploration. The first part of the thesis explores a novel mathematical way of cruising the space of S-matrices using the techniques from geometric function theory (GFT). This analysis leads to rigorous two-sided bounds on Wilson coefficients in the effective field theories (EFT). Using these GFT techniques, we study elastic scattering amplitudes of identical massive scalar Bosons, EFT amplitudes of elastic 2-2 photon, and graviton scattering and try to constrain the space of low energy effective field theories. In the second part of the thesis, we work out a systematic derivation of the Froissart-Martin bound starting with $4-$point Mellin amplitude for a holographic CFT.

    ↳ hep-thhep-phmath-phmath.CV+10 citations
47. 47*

    Directed flow of light flavor hadrons for Au+Au collisions at $\sqrt{S_{NN}}=$ 7.7-200 GeV

    Tribhuban Parida🇮🇳 · Sandeep Chatterjee🇮🇳

    We have studied the directed flow of light-flavor hadrons for Au + Au collisions at $\sqrt{S_{NN}}=$ 7.7 - 200 GeV. The initial condition is taken from a suitable Glauber model which is further evolved within the framework of relativistic hydrodynamics. Model calculations of the rapidity-odd directed flow ($v_1$) of identified light-flavor hadrons are compared with the available experimental data after suitably calibrating the initial condition to describe the rapidity dependence of charged particle multiplicity and net-proton yield. For reasonable choice of the initial condition, we are able to describe the measured rapidity and beam energy dependence of identified hadron $v_1$ including the observed $v_1$ splitting between baryons and anti-baryons.

    ↳ nucl-thhep-ph12 citations
48. 48*

    Primordial Black Hole Formation during a Strongly Coupled Crossover

    Albert Escrivà🇯🇵 · Javier G. Subils🇸🇪

    The final mass distribution of primordial black holes is sensitive to the equation of state of the Universe at the scales accessible by the power spectrum. Motivated by the presence of phase transitions in several beyond the Standard Model theories, some of which are strongly coupled, we analyze the production of primordial black holes during such phase transitions, which we model using the gauge/gravity duality. We focus in the (often regarded as physically uninteresting) case for which the phase transition is just a smooth crossover. We find an enhancement of primordial black hole production in the range $M_{\mathrm{PBH}}\in [10^{-16},10^{-6}]M_{\odot }$.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2023)·23 citations
49. 49*

    A solvable quantum field theory with asymptotic freedom in 3+1 dimensions

    Paul Romatschke🇺🇸

    Recently, Ai, Bender and Sarkar gave a prescription on how to obtain $\mathcal{P}\mathcal{T}$-symmetric field theory results from an analytic continuation of Hermitian field theories. I perform this analytic continuation for the massless (critical) O(N) model with quartic interaction in 3+1 dimensions. In the large N limit, this theory is exactly solvable, and has negative $\beta$-function in the ultraviolet, and a stable bound state in the infrared. The coupling diverges at a scale ${\Lambda }_c$, but can be continued into the far infrared. At finite temperature, the theory exhibits two phases separated by a second-order phase transition near $T_c\simeq {\Lambda }_c/\sqrt{e}$.

    ↳ hep-thhep-phnucl-thInt.J.Mod.Phys.A(2023)·28 citations
50. 50*

    Observing Signals of Spectral Features in the Cosmic-Ray Positrons and Electrons from Milky Way Pulsars

    Ilias Cholis🇺🇸 · Thressay Hoover🇺🇸

    The Alpha Magnetic Spectrometer (AMS-02) has provided unprecedented precision measurements of the electron and positron cosmic-ray fluxes and the positron fraction spectrum. At the higher energies, sources as energetic local pulsars, may contribute to both cosmic-ray species. The discreteness of the source population, can result in features both on the positron fraction measurement and in the respective electron and positron spectra. For the latter, those would coincide in energy and would contrast predictions of smooth spectra as from particle dark matter. In this work, using a library of pulsar population models for the local part of the Milky Way, we perform a power-spectrum analysis on the cosmic-ray positron fraction. We also develop a technique to cross-correlate the electron and positron fluxes. We show that both such analyses, can be used to search statistically for the presence of spectral wiggles in the cosmic-ray data. For a significant fraction of our pulsar simulations, those techniques are already sensitive enough to give a signal for the presence of those features above the regular noise, with forthcoming observations making them even more sensitive. Finally, by cross-correlating the AMS-02 electron and positron spectra, we find an intriguing first hint for a positive correlation between them, of the kind expected by a population of local pulsars.

    ↳ astro-ph.HEastro-ph.COhep-phPRD(2023)·7 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.