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Nuclear Theory·nucl-th

Wednesday·October 6, 2021

8 papers—4 primary·4 cross-listed

All8Primary4Cross-lists4
  1. 05

    [Submitted on 4 Oct 2021] (cross-list from hep-lat)

    Critical dynamics of relativistic diffusion

    Dominik Schweitzer🇩🇪 · Sören Schlichting🇩🇪 · Lorenz von Smekal🇩🇪

    We study the dynamics of self-interacting scalar fields with symmetry governed by a relativistic Israel-Stuart type diffusion equation in the vicinity of a critical point. We calculate spectral functions of the order parameter in mean-field approximation as well as using first-principles classical-statistical lattice simulations in real-time. We observe that the spectral functions are well-described by single Breit-Wigner shapes. Away from criticality, the dispersion matches the expectations from the mean-field approach. At the critical point, the spectral functions largely keep their Breit-Wigner shape, albeit with non-trivial power-law dispersion relations. We extract the characteristic time-scales as well as the dynamic critical exponent , verifying the existence of a dynamic scaling regime. In addition, we derive the universal scaling functions implied by the Breit-Wigner shape with critical power-law dispersion and show that they match the data. Considering equations of motion for a system coupled to a heat bath as well as an isolated system, we perform this study for two different dynamic universality classes, both in two and three spatial dimensions.

    Comments:
    35 pages, 11 figures
    Subjects:
    High Energy Physics — Lattice (hep-lat); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2110.01696 [pdf]
    NPB(2022)·25 citations
  2. 06

    [Submitted on 5 Oct 2021] (cross-list from hep-ph)

    Systematic study of hadronic excitation energy using Schottky anomaly

    Harunobu Akiyama🇯🇵 · Daisuke Jido🇯🇵

    We extract the excitation energy scales of the hadron spectra in a less model-dependent method using Schottky anomaly. Schottky anomaly is a thermodynamical phenomenon that the specific heat of a system consisting of a finite number of energy levels has a peak at finite temperature due to the energy gaps. Using the masses of all hadrons that are experimentally established, we obtain the excitation energy scales of the hadron spectra and investigate their flavor dependence.

    Comments:
    17 pages, 15 figures, 15 tables
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2110.01784 [pdf]
    PRD(2021)·1 citation
  3. 07

    [Submitted on 5 Oct 2021] (cross-list from hep-ph)

    Peaks of sound velocity in two color dense QCD: quark saturation effects and semishort range correlations

    Toru Kojo🇨🇳 · Daiki Suenaga🇯🇵

    We discuss stiffening of dense matter in two color QCD (QCD) where hadrons are mesons and diquark baryons. We study two models which describe a transition of matter from the Bose-Einstein-Condensation regime at low density to the Bardeen-Cooper-Schrieffer regime at high density. The first model is based on coherent states of diquarks, and the second is the Nambu-Jona-Lasinio model with diquark pairing terms. We particularly focus on how quark states are occupied as baryon density increases. We find that, due to the occupied quark levels, the ideal gas picture of diquarks breaks down at density significantly less than the density where baryon cores overlap. The saturation of quark states at low momenta stiffens equations of state. We also study the effects of interactions which depend on the quark occupation probability. We argue that equations of state become very stiff when the bulk part of the quark Fermi sea has the effective repulsion but the Fermi surface enjoys the attractive correlations. This disparity for different momentum domains is possible due to the strong channel dependence in gluon exchanges with momentum transfer of GeV. These concepts can be transferred from QCD to QCD in any numbers of colors.

    Comments:
    14 pages, 14 figures; v2, minor changes, published in PRD
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    2110.02100 [pdf]
    PRD(2022)·54 citations
  4. 08

    [Submitted on 5 Oct 2021] (cross-list from hep-ph)

    A novel formulation of the unintegrated gluon distribution for DIS

    Yacine Mehtar-Tani🇺🇸

    In this talk, we revisit inclusive DIS in the small limit and derive a new factorization formula that accounts for leading powers in both Bjorken and Regge limits. In this semi-classical description, we obtain a new unintegrated gluon distribution which encompasses both the dipole operator and the gluon Parton Distribution Function with an explicit dependence on the longitudinal momentum fraction .

    Comments:
    5 pages, 1 figure. Presented at the XXVIII International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS 2021), Stony Brook University, New York, USA, 12-16 April 2021. Submission to SciPost Proceedings
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2110.02105 [pdf]
    SciPost Phys.Proc.(2022)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE