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Nuclear Theory·nucl-th

Thursday·April 15, 2021

7 papers—2 primary·5 cross-listed

All7Primary2Cross-lists5
  1. 01

    [Submitted on 13 Apr 2021]

    Induced Surface and Curvature Tensions Equation of State of Hadrons with Relativistic Excluded Volumes and its Relation to Morphological Thermodynamics

    K.A. Bugaev🇺🇦 · N.S. Yakovenko🇺🇦 · P.V. Oliinyk🇺🇦 · E.G. Nikonov🇷🇺 · D.B. Blaschke🇵🇱 · L.V. Bravina🇳🇴 · E.E. Zabrodin🇳🇴

    An analytical formula that accurately accounts for the Lorentz contraction of the excluded volume of two relativistic hadrons with hard-core repulsion is worked out. Using the obtained expression we heuristically derive the equation of state of Boltzmann particles with relativistic excluded volumes in terms of system pressure and its surface and curvature tension coefficients. The behavior of effective excluded volumes of lightest baryons and mesons is studied at very high temperatures (particle number densities) and for very large values of degeneracy factors. Several parameterizations of the obtained equation of state demonstrate a universal asymptotics of the effective excluded volume at high particle number densities. It is peculiar, that the found maximal packing fraction of Lorentz contracted particles is very close to the dense packing limit of classical hard spheres of same radius . We show that the developed equation of state is the grand canonical formulation of the morphological thermodynamics approach applied to Lorentz contracted rigid spheres.

    Comments:
    15 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2104.06528 [pdf]
    Phys.Scripta(2021)·1 citation
  2. 02

    [Submitted on 14 Apr 2021]

    Unified quark-hadron EoS and critical endpoint in the QCD phase diagram

    David Blaschke🇵🇱

    We present a recent development towards a unified description of quark-hadron matter in the QCD phase diagram that is based on a cluster decomposition of the generalized Beth-Uhlenbeck approach to quark matter, selfconsistently coupled to Polyakov-loop and mesonic background fields. The Mott dissociation of hadrons under extreme conditions of temperature and density is triggered by chiral symmetry restoration and confining aspects are modeled by the coupling to the background mean fields. First results for the QCD phase diagram with the capability to describe critical endpoints as well as crossover-all-over are presented and an excellent agreement with lattice QCD on the temperature axis is obtained.

    Comments:
    10 pages, 3 figures, Contribution to the Proceedings of the Workshop on "Criticality in QCD and the Hadron Resonance Gas", Wroclaw, 31. July 2020
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2104.06961 [pdf]
    Acta Phys.Polon.Supp.(2021)·0 citations
  3. 03

    [Submitted on 16 Dec 2020] (cross-list from hep-th)

    Chiral hydrodynamics in strong external magnetic fields

    Martin Ammon🇩🇪 · Sebastian Grieninger🇩🇪 · Juan Hernandez🇨🇦 · Matthias Kaminski🇺🇸 · Roshan Koirala🇺🇸 · Julian Leiber🇩🇪 · Jackson Wu🇺🇸

    We construct the general hydrodynamic description of (3+1)-dimensional chiral charged (quantum) fluids subject to a strong external magnetic field with effective field theory methods. We determine the constitutive equations for the energy-momentum tensor and the axial charge current, in part from a generating functional. Furthermore, we derive the Kubo formulas which relate two-point functions of the energy-momentum tensor and charge current to 27 transport coefficients: 8 independent thermodynamic, 4 independent non-dissipative hydrodynamic, and 10 independent dissipative hydrodynamic transport coefficients. Five Onsager relations render 5 more transport coefficients dependent. We uncover four novel transport effects, which are encoded in what we call the shear-induced conductivity, the two expansion-induced longitudinal conductivities and the shear-induced Hall conductivity. Remarkably, the shear-induced Hall conductivity constitutes a novel non-dissipative transport effect. As a demonstration, we compute all transport coefficients explicitly in a strongly coupled quantum fluid via holography.

    Comments:
    matches version published in JHEP; 59 pages + appendices, 16 figures
    Subjects:
    High Energy Physics — Theory (hep-th); Strongly Correlated Electrons (cond-mat.str-el); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
    arXiv:
    2012.09183 [pdf]
    JHEP(2021)·64 citations
  4. 04

    [Submitted on 13 Apr 2021] (cross-list from hep-ph)

    Addendum to: Combined Constraints on First Generation Leptoquarks

    Andreas Crivellin · Luc Schnell

    In this addendum to arXiv:2101.07811 we discuss the implications of the recent CMS analysis of lepton flavour universality violation in non-resonant di-lepton pairs for first generation leptoquarks. As CMS finds more electron events than expected from background, this analysis prefers the LQ representations and which lead to constructive interference with the SM. In principle the excess could also be (partially) explained by the representations which are interfering destructively, as this would still lead to the right effect in bins with high invariant mass where the new physics contribution dominates. However, in these cases large couplings would be required which are excluded by other observables. The representations cannot improve the fit to the CMS data compared to the SM.

    Comments:
    8 pages, 3 figures, 3 tables
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2104.06417 [pdf]
    PRD(2021)·68 citations
  5. 05

    [Submitted on 13 Apr 2021] (cross-list from hep-th)

    Shear Viscosity at Infinite Coupling: A Field Theory Calculation

    Paul Romatschke🇺🇸

    I derive an exact integral expression for the ratio of shear viscosity over entropy density for the massless (critical) O(N) model at large N with quartic interactions. The calculation is set up and performed entirely from the field theory side using a non-perturbative resummation scheme that captures all contributions to leading order in large N. In 2+1d, is evaluated numerically at all values of the coupling. For infinite coupling, I find . I show that this strong coupling result for the viscosity is universal for a large class of interacting bosonic O(N) models.

    Comments:
    6 pages, 1 figure plus supplemental material; v2: fixed typos and buggy code for (84) in v1, corrected eta/s values; v3: typo in (9) corrected, Fig.1 updated (no change in results)
    Subjects:
    High Energy Physics — Theory (hep-th); Strongly Correlated Electrons (cond-mat.str-el); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2104.06435 [pdf]
    PRL(2021)·24 citations
  6. 06

    [Submitted on 14 Apr 2021] (cross-list from hep-lat)

    Fluctuations and correlations of net baryon number, electric charge and strangeness in a background magnetic field

    H.-T. Ding🇨🇳 · S.-T. Li🇨🇳 · Q. Shi🇨🇳 · X.-D. Wang🇨🇳

    We present results on the second-order fluctuations of and correlations among net baryon number, electric charge and strangeness in (2+1)-flavor lattice QCD in the presence of a background magnetic field. Simulations are performed using the tree-level improved gauge action and the highly improved staggered quark (HISQ) action with a fixed scale approach ( 0.117 fm). The light quark mass is set to be 1/10 of the physical strange quark mass and the corresponding pion mass is about 220 MeV at vanishing magnetic field. Simulations are performed on lattices with 9 values of varying from 96 to 6 corresponding to temperatures ranging from zero up to 281 MeV. The magnetic field strength is simulated with 15 different values up to 2.5 GeV at each nonzero temperature. We find that quadratic fluctuations and correlations do not show any singular behavior at zero temperature in the current window of while they develop peaked structures at nonzero temperatures as grows. By comparing the electric charge-related fluctuations and correlations with hadron resonance gas model calculations and ideal gas limits we find that the changes in degrees of freedom start at lower temperatures in stronger magnetic fields. Significant effects induced by magnetic fields on the isospin symmetry and ratios of net baryon number and baryon-strangeness correlation to strangeness fluctuation are observed, which could be useful for probing the existence of a magnetic field in heavy-ion collision experiments.

    Comments:
    12 pages, 7 figures, invited contribution to The European Physical Journal A-Hadrons and Nuclei: Topical Issue on "QCD Phase Diagram in Strong Magnetic Fields", minor revision
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2104.06843 [pdf]
    EPJA(2021)·56 citations
  7. 07

    [Submitted on 14 Apr 2021] (cross-list from hep-ph)

    Isovector EMC effect from global QCD analysis with MARATHON data

    C. Cocuzza🇺🇸 · C. E. Keppel🇺🇸 · H. Liu🇺🇸 · W. Melnitchouk🇺🇸 · A. Metz🇺🇸 · N. Sato🇺🇸 · A. W. Thomas🇦🇺

    We report the results of a Monte Carlo global QCD analysis of unpolarized parton distribution functions (PDFs), including for the first time constraints from ratios of He to H structure functions recently obtained by the MARATHON experiment at Jefferson Lab. Our simultaneous analysis of nucleon PDFs and nuclear effects in and nuclei reveals the first indication for an isovector nuclear EMC effect in light nuclei. We find that while the MARATHON data yield relatively weak constraints on the neutron to proton structure function ratio and on the PDF ratio, they suggest an enhanced nuclear effect on the -quark PDF in the bound proton, questioning the assumptions commonly made in nuclear PDF analyses.

    Comments:
    6 pages, 3 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2104.06946 [pdf]
    PRL(2021)·56 citations

Affiliations

first authorsco-authorsvia INSPIRE