Wed·Dec 15, 2021Wednesday·December 15, 2021

1. 01*

   Pursuing the Precision Study for Color Glass Condensate in Forward Hadron Productions

   Yu Shi🇨🇳 · Lei Wang🇨🇳 · Shu-Yi Wei🇮🇹 · Bo-Wen Xiao🇨🇳

   With the tremendous accomplishments of RHIC and the LHC experiments and the advent of the future Electron-Ion Collider on the horizon, the quest for compelling evidence of the color glass condensate (CGC) has become one of the most aspiring goals in the high energy Quantum Chromodynamics research. Pursuing this question requires developing the precision test of the CGC formalism. By systematically implementing the threshold resummation, we significantly improve the stability of the next-to-leading-order calculation in CGC for forward rapidity hadron productions in $pp$ and $pA$ collisions, especially in the high $p_T$ region, and obtain reliable descriptions of all existing data measured at RHIC and the LHC across all $p_T$ regions. Consequently, this technique can pave the way for the precision studies of the CGC next-to-leading-order predictions by confronting them with a large amount of precise data.

   hep-phhep-exnucl-exnucl-thPRL(2022)·64 citations
2. 02*

   Fermion and scalar two-component dark matter from a $Z_4$ symmetry

   Carlos E. Yaguna🇨🇴 · Óscar Zapata🇨🇴

   We revisit a two-component dark matter model in which the dark matter particles are a singlet fermion ($\psi$) and a singlet scalar ($S$), both stabilized by a single $Z_4$ symmetry. The model, which was proposed by Y. Cai and A. Spray, is remarkably simple, with its phenomenology determined by just five parameters: the two dark matter masses and three dimensionless couplings. In fact, $S$ interacts with the Standard Model particles via the usual Higgs-portal, whereas $\psi$ only interacts directly with $S$, via the Yukawa terms $\overline{{\psi }^c}(y_s+y_p{\gamma }^5)\psi S$. We consider the two possible mass hierarchies among the dark matter particles, $M_S<M_{\psi }$ and $M_{\psi }<M_S$, and numerically investigate the consistency of the model with current bounds. The main novelties of our analysis are the inclusion of the $y_p$ coupling, the update of the direct detection limits, and a more detailed characterization of the viable parameter space. For dark matter masses below $1.3$ TeV or so, we find that the model not only is compatible with all known constraints, but that it also gives rise to observable signals in future dark matter experiments. Our results show that both dark matter particles may be observed in direct detection experiments and that the most relevant indirect detection channel is due to the annihilation of $\psi$. We also argue that this setup can be extended to other $Z_N$ symmetries and additional dark matter particles.

   hep-phPRD(2022)·33 citations
3. 03*

   Detecting inhomogeneous chiral condensation from the bosonic two-point function in the $(1+1)$-dimensional Gross-Neveu model in the mean-field approximation

   Adrian Koenigstein🇩🇪 · Laurin Pannullo🇩🇪 · Stefan Rechenberger🇩🇪 · Martin J. Steil🇩🇪 · Marc Winstel🇩🇪

   The phase diagram of the $(1+1)$-dimensional Gross-Neveu model is reanalyzed for (non-)zero chemical potential and (non-)zero temperature within the mean-field approximation. By investigating the momentum dependence of the bosonic two-point function, the well-known second-order phase transition from the ${\mathbb{Z}}_2$ symmetric phase to the so-called inhomogeneous phase is detected. In the latter phase the chiral condensate is periodically varying in space and translational invariance is broken. This work is a proof of concept study that confirms that it is possible to correctly localize second-order phase transition lines between phases without condensation and phases of spatially inhomogeneous condensation via a stability analysis of the homogeneous phase. To complement other works relying on this technique, the stability analysis is explained in detail and its limitations and successes are discussed in context of the Gross-Neveu model. Additionally, we present explicit results for the bosonic wave-function renormalization in the mean-field approximation, which is extracted analytically from the bosonic two-point function. We find regions -- a so-called moat regime -- where the wave function renormalization is negative accompanying the inhomogeneous phase as expected.

   hep-phcond-mat.str-elnucl-thJ.Phys.A(2022)·45 citations
4. 04*

   The Infrared Structure of Perturbative Gauge Theories

   Neelima Agarwal · Lorenzo Magnea🇨🇭 · Chiara Signorile-Signorile🇩🇪 · Anurag Tripathi🇮🇳

   Infrared divergences in the perturbative expansion of gauge theory amplitudes and cross sections have been a focus of theoretical investigations for almost a century. New insights still continue to emerge, as higher perturbative orders are explored, and high-precision phenomenological applications demand an ever more refined understanding. This review aims to provide a pedagogical overview of the subject. We briefly cover some of the early historical results, we provide some simple examples of low-order applications in the context of perturbative QCD, and discuss the necessary tools to extend these results to all perturbative orders. Finally, we describe recent developments concerning the calculation of soft anomalous dimensions in multi-particle scattering amplitudes at high orders, and we provide a brief introduction to the very active field of infrared subtraction for the calculation of differential distributions at colliders.

   hep-phhep-thPhys.Rept.(2023)·95 citations
5. 05*

   Dilepton Helical Production in a Vortical Quark-Gluon Plasma

   Lihua Dong🇨🇳 · Shu Lin🇨🇳

   In this paper, we propose an observable counting a weighted difference between right-handed and left-handed lepton pairs, which is coined dilepton helical rate. The weight is the momentum difference of the lepton pairs projected onto an auxiliary vector. We derive the helical rate in a quark-gluon plasma with a vorticity in the limit when the quark and lepton masses are ignored. We find the helical rate is maximized when the auxiliary vector is parallel to the vorticity, in which case it has a nearly spherical oblate ellipsoidal distribution. We propose that it can be used as a vortical-meter for quark-gluon plasma.

   hep-phnucl-exnucl-thEPJA(2022)·10 citations
6. 06*

   From theory to precision modelling of strong-field QED in the transition regime

   Alexander J. Macleod (for the LUXE collaboration)🇨🇿

   The combination of energetic electron beams, delivered from conventional accelerators at a high repetition rate, and ultraintense lasers, makes it possible to perform precision measurements of strong-field QED. The LUXE collaboration aims to perform precision measurements of nonlinear Compton scattering and Breit-Wheeler pair creation in the transition from the perturbative to nonperturbative regimes. Here we present an overview of recent developments in the modelling of strong-field QED processes, which are needed to reach the required precision of a few percent for intensity parameters $0.1<\xi <10$. We discuss how to go from plane wave QED results to numerical simulations and present predicted signals and error estimates.

   hep-phJ.Phys.Conf.Ser.(2022)·6 citations
7. 07*

   Global analysis of electroweak data in the Standard Model

   J. de Blas🇪🇸 · M. Ciuchini🇮🇹 · E. Franco🇮🇹 · A. Goncalves🇺🇸 · S. Mishima🇯🇵 · M. Pierini🇨🇭 · L. Reina🇺🇸 · L. Silvestrini🇮🇹

   We perform a global fit of electroweak data within the Standard Model, using state-of-the art experimental and theoretical results, including a determination of the electromagnetic coupling at the electroweak scale based on recent lattice calculations. In addition to the posteriors for all parameters and observables obtained from the global fit, we present indirect determinations for all parameters and predictions for all observables. Furthermore, we present full predictions, obtained using only the experimental information on Standard Model parameters, and a fully indirect determination of Standard Model parameters using only experimental information on electroweak data. Finally, we discuss in detail the compatibility of experimental data with the Standard Model and find a global p-value of 0.5.

   hep-phhep-exPRD(2022)·116 citations
8. 08*

   Are multimodal events a sign of the strangelet passage through the matter?

   Ewa Gładysz-Dziaduś🇵🇱

   A possible connection between the multimodal events (MME) observed in the very high energy extensive air showers by the HORIZON-T experiment and the so-called strongly penetrating component observed in the homogenous lead emulsion chambers of the Pamir and Chacaltaya Experiments was studied. We found that both experimental observations could be connected one to the other, and could be the manifestation of the same physical process, i.e. penetration of a strangelet through the matter. In the first case a strangelet produces the many-maxima long range cascades observed in the homogenous lead emulsion chambers. In the second case the successive interactions of a strangelet in the air are seen in the HORIZON-T detectors as the consecutive signals. Time intervals between signals are between several dozen to several hundred nanoseconds. I

   hep-ph0 citations
9. 09*

   The tau lepton Monte Carlo Event Generation -- imprinting New Physics models with exotic scalar or vector states into simulation samples

   Sw. Banerjee🇺🇸 · D. Biswas🇺🇸 · T. Przedzinski🇵🇱 · Z. Was🇵🇱

   The Monte Carlo for lepton pair production andtau decays consist of KKMC for lepton pair production, tauola for tau lepton decays and photos for radiative corrections in decays. An effort for adaptation of the system for precision data being collected at the Belle II experiment included simulation of additional light lepton pairs. Extension to processes where lepton pair is produced through narrow resonances, like dark photon or dark scalar phi resonances, was straight forward. Modified programs versions are available in stand-alone format from gitlab repository or through the basf2 system of Belle II software. It was explained recently during the International Workshop on Tau Lepton Physics September, 2021, Bloomington IN. Now we concentrate on simulations for phi resonance, a hypothetical object which could be responsible for anomalous moment g-2 in Z-\tau-\tau interactions through virtual contributions.

   hep-phhep-ex2 citations
10. 10*

    A 331 Model for Lepton Flavor Universality Violation in $B$ Decays

    Soumia Lebbal🇩🇿 · Jamal Mimouni🇩🇿 · Noureddine Mebarki🇩🇿

    Lepton Flavor Universality Violation (LFUV) in $B$ decays in both neutral $b\to s{l}^{+}{l}^{-}$ and charged $b\to cl{\bar{\nu }}_l$ processes observed in the ratios $R_{K^{(\ast )}}$ and $R_{D^{(\ast )}}$ is investigated in the framework of a model based on the extended symmetry gauge $SU(3{)}_C\otimes SU(3{)}_L\otimes U(1{)}_X$ whose leptonic sector consists of five triplets. It is shown that in order to explain the experimentally observed deviations from the Standard Model in these flavor changing transitions, a non-minimal version of the model has to be considered. We investigate the ability of this model in accommodating the model-independent scenarios currently favored by global fits.

    hep-phInt.J.Mod.Phys.A(2022)·1 citation
11. 11*

    New charged Higgs boson discovery channel at the LHC

    Rachid Benbrik (1)🇲🇦 · Mohammed Boukidi (1)🇲🇦 · Bouzid Manaut (2)🇲🇦 · Mohamed Ouchemhou (1)🇲🇦 · Souad Semlali (3)🇬🇧 · Souad Taj (2) ((1) Polydisciplinary Faculty, Laboratory of Fundamental and Applied Physics, Cadi Ayyad University, Sidi Bouzid, Safi, Morocco, (2) Polydisciplinary Faculty, Laboratory of Research in Physics and Engineering Sciences, Team of Modern and Applied Physics, Sultan Moulay Slimane University, Beni Mellal, Morocco, (3) School of Physics and Astronomy, University of Southampton, United Kingdom)🇲🇦

    The ATLAS and CMS experiments have an ambitious search program for charged Higgs bosons. The two main searches for $H^{\pm }$ at the LHC have traditionally been performed in the $\tau \nu$ and $tb$ decay channels, as they provide the opportunity to probe complementary regions of the Minimal SuperSymmetric Model (MSSM) parameter space. Charged Higgs bosons may decay also to light quarks, $H^{\pm }\to cs/cb$, which represent an additional probe for the mass range below $m_t$. In this work, we focus on $H^{\pm }\to \mu \nu$ as an alternative channel in the context of two Higgs doublet model type III. We explored the prospect of looking $pp\to tb{H}^{\pm }$, followed by $H^{\pm }\to \mu \nu$ signal at the LHC. Such a scenario appears in 2HDM type-III where couplings of the charged Higgs are enhanced to $\mu \nu$. Almost all the experimental searches rely on the production and decay of the charged Higgs are taken into account. We show that for a such scenario, the above signal is dominant for most of the parameter space, and $H^{\pm }\to \mu \nu$ can be an excellent complementary search. Benchmarks points are proposed for further Monte Carlo analysis.

    hep-ph8 citations
12. 12*

    Breaking the conformal freedom of spacetime with supernova neutrino imaging

    Joonas Ilmavirta🇫🇮 · Gunther Uhlmann🇫🇮

    It is known that a geometric measurement of the light cones of supernovae determines the conformal class of the visible part of the spacetime. The conformal factor is physically meaningful but cannot be determined geometrically by anything with zero mass, such as the photon. We show that measuring the neutrino cones in addition to light cones completely removes this gauge freedom. We describe the physical model in great detail, including why ultrarelativistic neutrinos are the only option.

    hep-phmath.APmath.DG0 citations
13. 13*

    Universal structure of radiative QED amplitudes at one loop

    Tim Engel🇨🇭 · Adrian Signer🇨🇭 · Yannick Ulrich🇬🇧

    We present two novel results about the universal structure of radiative QED amplitudes in the soft and in the collinear limit. On the one hand, we extend the well-known Low-Burnett-Kroll theorem to the one-loop level and give the explicit relation between the radiative and non-radiative amplitude at subleading power in the soft limit. On the other hand, we consider a factorisation formula at leading power in the limit where the emitted photon becomes collinear to a light fermion and provide the corresponding one-loop splitting function. In addition to being interesting in their own right these findings are particularly relevant in the context of fully-differential higher-order QED calculations. One of the main challenges in this regard is the numerical stability of radiative contributions in the soft and collinear regions. The results presented here allow for a stabilisation of real-virtual amplitudes in these delicate phase-space regions by switching to the corresponding approximation without the need of explicit computations.

    hep-phJHEP(2022)·37 citations
14. 14*

    Two-loop amplitude for mixed QCD-EW corrections to $gg\to Hg$

    Matteo Becchetti🇮🇹 · Francesco Moriello🇨🇭 · Armin Schweitzer🇨🇭

    We report on the two-loop amplitude computation for the mixed QCD-electroweak corrections to the process $gg\to Hg$, with exact dependence on the electroweak boson masses. This amplitude has been employed in the computation of next-to-leading order (NLO) mixed QCD-electroweak corrections to the Higgs-boson production rate in arXiv:2010.09451. The master integrals that appear in the amplitude are evaluated by means of generalized power series expansions, which allows for fast and high-precision numerical evaluation of the amplitude in the physical phase-space, proving to be a powerful tool for phenomenological applications.

    hep-phJHEP(2022)·16 citations
15. 15*

    QCD at high temperature and density: selected highlights

    Jon-Ivar Skullerud🇮🇪

    I review some of the recent progress in QCD at high temperature and density, with a focus on the nature of the high-temperature transition; cold and dense matter; and hadron properties and transport coefficients at high temperature.

    hep-phhep-latnucl-thEPJ Web Conf.(2022)·1 citation
16. 16*

    Machine learning a manifold

    Sean Craven🇬🇧 · Djuna Croon🇬🇧 · Daniel Cutting🇫🇮 · Rachel Houtz🇬🇧

    We propose a simple method to identify a continuous Lie algebra symmetry in a dataset through regression by an artificial neural network. Our proposal takes advantage of the $\mathcal{O}({ϵ}^2)$ scaling of the output variable under infinitesimal symmetry transformations on the input variables. As symmetry transformations are generated post-training, the methodology does not rely on sampling of the full representation space or binning of the dataset, and the possibility of false identification is minimised. We demonstrate our method in the SU(3)-symmetric (non-) linear $\Sigma$ model.

    hep-phcs.LGPRD(2022)·12 citations
17. 17*

    SpaceQ -- Direct Detection of Ultralight Dark Matter with Space Quantum Sensors

    Yu-Dai Tsai🇺🇸 · Joshua Eby🇯🇵 · Marianna S. Safronova🇺🇸

    Recent advances in quantum sensors, including atomic clocks, enable searches for a broad range of dark matter candidates. The question of the dark matter distribution in the Solar system critically affects the reach of dark matter direct detection experiments. Partly motivated by the NASA Deep Space Atomic Clock (DSAC), we show that space quantum sensors present new opportunities for ultralight dark matter searches, especially for dark matter states bound to the Sun. We show that space quantum sensors can probe unexplored parameter space of ultralight dark matter, covering theoretical relaxion targets motivated by naturalness and Higgs mixing. If an atomic clock were able to make measurements on the interior of the solar system, it could probe this highly sensitive region directly and set very strong constraints on the existence of such a bound-state halo in our solar system. We present sensitivity projections for space-based probes of ultralight dark matter which couples to electron, photon, and gluon fields, based on current and future atomic, molecular, and nuclear clocks.

    hep-phastro-ph.COphysics.atom-phNature Astron.(2023)·61 citations
18. 18*

    Factorization for Azimuthal Asymmetries in SIDIS at Next-to-Leading Power

    Markus A. Ebert🇩🇪 · Anjie Gao🇺🇸 · Iain W. Stewart🇺🇸

    Differential measurements of the semi-inclusive deep inelastic scattering (SIDIS) process with polarized beams provide important information on the three-dimensional structure of hadrons. Among the various observables are azimuthal asymmetries that start at subleading power, and which give access to novel transverse momentum dependent distributions (TMDs). Theoretical predictions for these distributions are currently based on the parton model rather than a rigorous factorization based analysis. Working under the assumption that leading power Glauber interactions do not spoil factorization at this order, we use the Soft Collinear Effective Theory to derive a complete factorization formula for power suppressed hard scattering effects in SIDIS. This yields generalized definitions of the TMDs that depend on two longitudinal momentum fractions (one of them only relevant beyond tree level), and a complete proof that only the same leading power soft function appears and can be absorbed into the TMD distributions at this order. We also show that perturbative corrections can be accounted for with only one new hard coefficient. Factorization formulae are given for all spin dependent structure functions which start at next-to-leading power. Prospects for improved subleading power predictions that include resummation are discussed.

    hep-phnucl-thJHEP(2022)·58 citations
19. 19*

    Theoretical predictions for inclusive $B\to X_u\tau \bar{\nu }$ decay

    Zoltan Ligeti🇺🇸 · Michael Luke🇨🇦 · Frank J. Tackmann🇩🇪

    With the expected large increase in data sets, previously not measured decays will be studied at Belle II. We derive standard model predictions for the $B\to X_u\tau \bar{\nu }$ decay rate and distributions. The region in the lepton energy spectrum where higher-dimension operators in the local OPE need to be resummed into the $b$-quark light-cone distribution function is a significantly greater fraction of the phase space than for massless leptons. The finite $\tau$ mass has the novel effect of shifting and squeezing how the distribution function enters the lepton energy spectrum. We also derive new predictions for the $\tau$ polarization.

    hep-phhep-exPRD(2022)·16 citations
20. 20*

    Friction pressure on relativistic bubble walls

    Yann Gouttenoire🇮🇱 · Ryusuke Jinno🇩🇪 · Filippo Sala🇫🇷

    During a cosmological first-order phase transition, particles of the plasma crossing the bubble walls can radiate a gauge boson. The resulting pressure cannot be computed perturbatively for large coupling constant and/or large supercooling. We resum the real and virtual emissions at all leading-log orders, both analytically and numerically using a Monte-Carlo simulation. We find that radiated bosons are dominantly soft and that the resulting retarding pressure on relativistic bubble walls is linear both in the Lorentz boost and in the order parameter, up to a log. We further quantitatively discuss IR cut-offs, wall thickness effects, the impact of various approximations entering the calculation, and comment on the fate of radiated bosons that are reflected.

    hep-phastro-ph.COgr-qcJHEP(2022)·156 citations
21. 21*

    High-precision search for dark photon dark matter with the Parkes Pulsar Timing Array

    Xiao Xue🇩🇪 · Zi-Qing Xia🇨🇳 · Xingjiang Zhu🇨🇳 · Yue Zhao🇺🇸 · Jing Shu🇨🇳 · Qiang Yuan🇨🇳 · N. D. Ramesh Bhat🇦🇺 · Andrew D. Cameron🇺🇸 · Shi Dai🇦🇺 · Yi Feng🇨🇳 · Boris Goncharov🇦🇺 · George Hobbs🇦🇺 and 11 other authors

    The nature of dark matter remains obscure in spite of decades of experimental efforts. The mass of dark matter candidates can span a wide range, and its coupling with the Standard Model sector remains uncertain. All these unknowns make the etection of dark matter extremely challenging. Ultralight dark matter, with $m\sim 10^{-22}$ eV, is proposed to reconcile the disagreements between observations and predictions from simulations of small-scale structures in the cold dark matter paradigm, while remaining consistent with other observations. Because of its large de Broglie wavelength and large local occupation number within galaxies, ultralight dark matter behaves like a coherently oscillating background field with an oscillating frequency dependent on its mass. If the dark matter particle is a spin-1 dark photon, such as the $U(1{)}_B$ or $U(1{)}_{B-L}$ gauge boson, it can induce an external oscillating force and lead to displacements of test masses. Such an effect would be observable in the form of periodic variations in the arrival times of radio pulses from highly stable millisecond pulsars. In this study, we search for evidence of ultralight dark photon dark matter (DPDM) using 14-year high-precision observations of 26 pulsars collected with the Parkes Pulsar Timing Array. While no statistically significant signal is found, we place constraints on coupling constants for the $U(1{)}_B$ and $U(1{)}_{B-L}$ DPDM. Compared with other experiments, the limits on the dimensionless coupling constant $ϵ$ achieved in our study are improved by up to two orders of magnitude when the dark photon mass is smaller than $3\times 10^{-22}$~eV ($10^{-22}$~eV) for the $U(1{)}_B$ ($U(1{)}_{B-L}$) scenario.

    hep-phastro-ph.COastro-ph.GAgr-qcPRResearch(2022)·44 citations
22. 22*

    Constraints on subleading interactions in beta decay Lagrangian

    Adam Falkowski🇫🇷 · Martín González-Alonso🇪🇸 · Ajdin Palavrić🇨🇭 · Antonio Rodríguez-Sánchez🇫🇷

    We discuss the effective field theory (EFT) for nuclear beta decay. The general quark-level EFT describing charged-current interactions between quarks and leptons is matched to the nucleon-level non-relativistic EFT at the O(MeV) momentum scale characteristic for beta transitions. The matching takes into account, for the first time, the effect of all possible beyond-the-Standard-Model interactions at the subleading order in the recoil momentum. We calculate the impact of all the Wilson coefficients of the leading and subleading EFT Lagrangian on the differential decay width in allowed beta transitions. As an example application, we show how the existing experimental data constrain the subleading Wilson coefficients corresponding to pseudoscalar, weak magnetism, and induced tensor interactions. The data display a 3.5 sigma evidence for nucleon weak magnetism, in agreement with the theory prediction based on isospin symmetry.

    hep-phJHEP(2024)·34 citations
23. 23*

    Renormalized $ϵ$-finite master integrals and their virtues: the three-loop self energy case

    Stephen P. Martin🇺🇸

    Loop diagram calculations typically rely on reduction to a finite set of master integrals in $4-2ϵ$ dimensions. It has been shown that for any problem, the masters can be chosen so that their coefficients are finite as $ϵ\to 0$. I propose a definition of renormalized $ϵ$-finite master integrals, which incorporate ultraviolet divergence subtractions in a specific way. A key advantage of this choice is that in expressions for physical observables, expansions to positive powers in $ϵ$ are never needed. As an example, I provide the subtractions for general three-loop self-energy integrals. The differential equations method is used to compute numerically the renormalized $ϵ$-finite master integrals for arbitrary external momentum invariant, in special cases with internal masses equal to a single scale or zero. These include the ones necessary for the three-loop QCD corrections to the self-energies of the W, Z, and Higgs bosons. In principle, the same method should provide for numerical computation of general three-loop self energies with any masses.

    hep-phPRD(2022)·9 citations
24. 24*

    Graviton particle statistics and coherent states from classical scattering amplitudes

    Ruth Britto🇮🇪 · Riccardo Gonzo🇮🇪 · Guy R.Jehu🇮🇪

    In the two-body scattering problem in general relativity, we study the final graviton particle distribution using a perturbative approach. We compute the mean, the variance and the factorial moments of the distribution from the expectation value of the graviton number operator in the KMOC formalism. For minimally coupled scalar particles, the leading deviation from the Poissonian distribution is given by the unitarity cut involving the six-point tree amplitude with the emission of two gravitons. We compute this amplitude in two independent ways. First, we use an extension of the Cheung-Remmen parametrization that includes minimally coupled scalars. We then repeat the calculation using on-shell BCFW-like techniques, finding complete agreement. In the classical limit, this amplitude gives a purely quantum contribution, proving that we can describe the final semiclassical radiation state as a coherent state at least up to order $\mathcal{O}(G^4)$ for classical radiative observables. Finally, we give general arguments about why we expect this to hold also at higher orders in perturbation theory.

    ↳ hep-thgr-qchep-phJHEP(2022)·52 citations
25. 25*

    Bottomonia screening masses from $2+1$ flavor QCD

    Peter Petreczky🇺🇸 · Sayantan Sharma🇮🇳 · Johannes Heinrich Weber🇩🇪

    The sequential melting of the bottomonium states is one of the important signals for the existence of a quark gluon plasma. The study of bottomonia spectral functions on the lattice is a difficult task for many reasons. Calculations based on NRQCD, that are commonly used for such purpose, are not applicable at high temperatures. In this work we propose a new method to study this problem by calculating the spatial screening masses of bottomonium states. We calculate the spatial meson correlators and extract the screening masses for mesons in different quantum channels using highly improved staggered quark (HISQ) action for bottom quarks and dynamical $2+1$ flavor QCD HISQ gauge configurations. The typical lattices we choose are of size $N_s^3\times N_{\tau }$ where $N_s=4N_{\tau }$ and $N_{\tau }=8,10,12$. We consider the temperature range $T=300$-$1000$ MeV. We show that for $T>500$ MeV the temperature dependence of the screening masses of the ground state bottomonia are compatible with the expectations based on uncorrelated quark anti-quark pairs.

    ↳ hep-lathep-phnucl-th1 citation
26. 26*

    Thermal and annihilation radiation in the quark nugget model of dark matter

    V.V. Flambaum🇦🇺 · I.B. Samsonov🇦🇺

    The Quark Nugget (QN) model of dark matter suggests that the dark matter may consist of compact composite objects of quark matter. Although such composite particles can strongly interact with visible matter, they may remain undetected because of a small cross section to mass ratio. We focus on anti-QNs made of antiquarks since they are heated by annihilation with visible matter and radiate. We study the radiation spectrum and power from anti-QNs in our galaxy and compare them with satellite observations. Thermal radiation from anti-QN is produced by fluctuations of the positron density. We calculate the thermal radiation of anti-QNs with the use of the Mie theory and found its ratio to the black-body radiation. This allows us to find the equilibrium temperature of anti-QNs in the interstellar medium and determine their contribution to the observed diffuse background radiation in our galaxy in different frequency intervals, from radio to UV. We also consider non-thermal radiations from anti-QNs which are produced by products of annihilations of particles of the interstellar gas with anti-QNs. Such radiations include photons from decays of ${\pi }^0$ mesons, synchrotron, bremsstrahlung and transition radiations from ${\pi }^{\pm }$ mesons, electrons and positrons. Synchrotron radiation in MHz frequency range and flux of photons from ${\pi }^0$ decays may be above the detection threshold in such detectors as Fermi-LAT.

    ↳ astro-ph.COastro-ph.GAastro-ph.HEhep-phPRD(2022)·10 citations
27. 27*

    Nucleon Helicity Generalized Parton Distribution at Physical Pion Mass from Lattice QCD

    Huey-Wen Lin🇺🇸

    The generalized parton distributions (GPDs) offer a window on three-dimensional imaging of the nucleon, providing understanding of how the fundamental properties of the nucleon, such as its mass and spin, arise from the underlying quark and gluon degrees of freedom. In this work, we present the first lattice calculation of the nucleon isovector helicity GPD at physical pion mass, using an $a\approx 0.09$ fm lattice ensemble with 2+1+1 flavors of highly improved staggered quarks generated by MILC Collaboration. We perform the GPD calculation in Breit frame using averaged nucleon boost momentum $P_z\approx 2.2$ GeV with nonzero momentum transfers in $[0.2,1.0]{\text{ GeV}}^2$. Nonperturbative renormalization in RI/MOM scheme is used to obtain the quasi-distribution before matching to the lightcone GPDs. The three-dimensional distribution $\tilde{H}(x,Q^2)$ is presented, along with the three-dimensional nucleon tomography and impact-parameter--dependent distribution for selected Bjorken $x$ at $\mu =3$ GeV in $\overline{\text{MS}}$ scheme.

    ↳ hep-lathep-phnucl-thPLB(2022)·88 citations
28. 28*

    Embedding a critical point in a hadron to quark-gluon crossover equation of state

    J. I. Kapusta🇺🇸 · C. Plumberg🇺🇸 · T. Welle🇺🇸

    Lattice QCD simulations have shown unequivocally that the transition from hadrons to quarks and gluons is a crossover when the baryon chemical potential is zero or small. Many model calculations predict the existence of a critical point at a value of the chemical potential where current lattice simulations are unreliable. We show how to embed a critical point in a smooth background equation of state so as to yield the critical exponents and critical amplitude ratios expected of a transition in the same universality class as the liquid-gas phase transition and the 3D Ising model. The resulting equation of state has parameters which may be inferred by hydrodynamic modeling of heavy ion collisions in the Beam Energy Scan II at the Relativistic Heavy Ion Collider or in experiments at other accelerators.

    ↳ nucl-thhep-phPRC(2022)·15 citations
29. 29*

    Minimal embedding of the Standard Model into intersecting D-brane configurations with a bulk leptonic $U(1)$

    Ignatios Antoniadis🇫🇷 · François Rondeau🇫🇷

    It has been recently shown that the discrepancy between the theoretical and experimental values of the anomalous magnetic moment of the muon can be fully accommodated by considering the contribution of few Kaluza-Klein (KK) states of the gauged lepton number with masses lighter than the LEP energy, consistently with present experimental limits. In this article, we construct the minimal embedding of the Standard Model (SM) into D-brane configurations with a gauged lepton number. In order to give rise to such KK modes, the lepton number gauge boson must live on an abelian $U(1{)}_L$ brane extended along at least one "large" extra dimension in the bulk, with a compactification scale $M_L\sim \mathcal{O}(10-10^2\mathrm{GeV})$ for a string scale $M_s\sim 10\mathrm{TeV}$. As a consequence, $U(1{)}_L$ cannot participate to the hypercharge linear combination. We show that the minimal realisation of this framework contains five stacks of branes: the SM color $U(3{)}_c$, weak $U(2{)}_w$ and abelian $U(1)$ stacks extended effectively only in four dimensions, the bulk $U(1{)}_L$, as well as a fifth $U(1{)}^{{}^{\prime }}$ brane. With these five abelian factors, one finds besides the hypercharge a second anomaly-free linear combination which does not couple to the SM spectrum, both in the non-supersymmetric case as well as in the minimal supersymmetric extension of the model. It is also shown how the right-handed neutrino can be implemented in the spectrum, and how fermions arising from the two non-SM branes and coupled to the SM through the $U(1{)}_L$ KK modes can provide Dark Matter candidates. Finally, the possibility of breaking Lepton Flavour Universality is studied by replacing $U(1{)}_L$ with a brane gauging only the muonic lepton number, avoiding most experimental constraints and enlarging the parameter space for explaining the discrepancy on the muon magnetic moment.

    ↳ hep-thhep-phEPJC(2022)·10 citations
30. 30*

    Primordial Black Hole Generation in a Two-field Inflationary Model

    Lilia Anguelova🇧🇬

    We summarize our work on the generation of primordial black holes in a type of two-field inflationary models. The key ingredient is a sharp turn of the background trajectory in field space. We show that certain classes of solutions to the equations of motion exhibit precisely this kind of behavior. Among them we find solutions, which describe a transition between an ultra-slow roll and a slow roll phases of inflation.

    ↳ hep-thastro-ph.COhep-phSpringer Proc.Math.Stat.(2022)·10 citations
31. 31*

    Axion anomalies

    Peter Adshead🇺🇸 · Kaloian D. Lozanov🇺🇸

    We study fermions derivatively coupled to axion-like or pseudoscalar fields, and show that the axial vector current of the fermions is not conserved in the limit where the fermion is massless. This apparent violation of the classical chiral symmetry is due to the background axion field. We compute the contributions to this anomalous Ward identity due to the pseudoscalar field alone, which arise in Minkowski space, as well as the effects due to an interaction with an external gravitational field. For the case of massless fermions, these interactions induce terms in the axion effective action that can be removed by the addition of local counterterms. We demonstrate that these counterterms are generated by the transformation of the path integral measure when transforming the theory from a form where the chiral symmetry is manifest to one where the symmetry is only apparent after using the classical equations of motion. We work perturbatively in Minkowski space and include the effects of interactions with a linearized gravitational field. Using the heat kernel method, we study the transformation properties of the path integral measure, and include the effects of non-linear gravity as well as interactions with gauge fields. Finally, we verify our relation by considering derivatively coupled fermions during pseudoscalar-driven inflation and computing the divergence of the axial current in de Sitter spacetime.

    ↳ hep-thastro-ph.COgr-qchep-phJHEP(2022)·8 citations
32. 32*

    Multi-messenger detection prospects of gamma-ray burst afterglows with optical jumps

    Ersilia Guarini🇩🇰 · Irene Tamborra🇩🇰 · Damien Bégué🇮🇱 · Tetyana Pitik🇩🇰 · Jochen Greiner🇩🇪

    Some afterglow light curves of gamma-ray bursts (GRBs) exhibit very complex temporal and spectral features, such as a sudden intensity jump about one hour after the prompt emission in the optical band. We assume that this feature is due to the late collision of two relativistic shells and investigate the corresponding high-energy neutrino emission within a multi-messenger framework, while contrasting our findings with the ones from the classic afterglow model. For a constant density circumburst medium, the total number of emitted neutrinos can increase by about an order of magnitude when an optical jump occurs with respect to the self-similar afterglow scenario. By exploring the detection prospects with the IceCube Neutrino Observatory and future radio arrays such as IceCube-Gen2 radio, RNO-G and GRAND200k, as well as the POEMMA spacecraft, we conclude that the detection of neutrinos with IceCube-Gen2 radio could enable us to constrain the fraction of GRB afterglows with a jump as well as the properties of the circumburst medium. We also investigate the neutrino signal expected for the afterglows of GRB 100621A and a GRB 130427A-like burst with an optical jump. The detection of neutrinos from GRB afterglows could be crucial to explore the yet-to-be unveiled mechanism powering the optical jumps.

    ↳ astro-ph.HEhep-phJCAP(2022)·14 citations
33. 33*

    Role of focusing distance in picosecond laser-induced Cu plasma spectra

    Linyu Chen · Hu Deng · Zhixiang Wu · Zhonggang Xiong · Jin Guo · Quancheng Liu · Akwasi Danso Samuel · Liping Shang

    To study the effects of focusing distance on the characteristics of copper plasma, a picosecond laser was utilized to ablate a pure copper plate to generate a plasma spectrum. Following numerous experiments on the subject, three significant factors have been determined: lens focal length, pulse energy and the lens-to-sample distance. These factors were employed to analyze the spectral intensity, plasma temperature and electron density in the local thermodynamic equilibrium (LTE) and optically thin condition. Due to the shielding effects of mixed plasma, the strongest spectral intensity can be obtained in the pre-focused case rather than on the focus, no matter how much beam irradiance was employed. The more intensive the beam irradiance is, the more the optimal position is distant from the focal point. Similarly, the evolution of plasma temperature and electron density was shown a peak in the pre-focused case, which is consistent with the trend of spectral intensity. For the case of extremely high irradiance (on the focus), the shielding effects become more apparent and the resultant above three factors decreased sharply. When a longer-focal-length lens was employed, the spectral intensity exhibited an obvious bimodal trend. In the pre-focused case, a longer-focal-length lens is helpful to eliminate the effects of the roughness of the target surface compared with a shorter one. Finally, the assumed LTE was validated by McWhirter relation, plasma relaxation time and diffusion length, and the optically thin condition also validated by spectral intensity ratio. We hope this work could be an important reference for the future design of highly optimized experiments for Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS).

    ↳ physics.plasm-phhep-phAdv.High Energy Phys.(2022)·0 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.