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Nuclear Theory·nucl-th

Wednesday·September 22, 2021

8 papers—4 primary·4 cross-listed

All8Primary4Cross-lists4
  1. 05

    [Submitted on 18 Sept 2021] (cross-list from hep-ph)

    Kinetic theory of overpopulated gluon systems with inelastic processes

    Zhengyu Chen🇨🇳

    In this work, the role of inelastic processes in the formation of a transient Bose-Einstein condensation (BEC) is investigated based on kinetic theory. We calculate the condensation rate for an overpopulated gluon system which is assumed to be in thermal equilibrium and with the presence of a BEC. The matrix elements of the inelastic processes are chosen as the isotropic one and the gluons are considered to have a finite mass. Our calculations indicate that the inelastic processes can hinder the formation of a BEC since the negatively infinite net condensation rate can destroy any BEC instantly.

    Comments:
    new discussion on the infinite terms; Sec.III, Subsection B deleted; references updated. arXiv admin note: text overlap with arXiv:1703.02495 by other authors
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2109.08887 [pdf]
    IJMPE(2023)·0 citations
  2. 06

    [Submitted on 20 Sept 2021] (cross-list from nucl-ex)

    System Size and Flavour Dependence of Chemical Freeze-out Temperatures in ALICE Data from pp, pPb and PbPb Collisions at LHC Energies

    Fernando Antonio Flor🇺🇸 · Gabrielle Olinger🇺🇸 · René Bellwied🇺🇸

    We present the system size and flavour dependence of the chemical freeze-out temperature () at vanishing baryo-chemical potential calculated via thermal fits to experimental yields for several multiplicity classes in pp, pPb and PbPb collisions measured by ALICE. Using the Thermal-FIST Hadron Resonance Gas model package, we compare the quality of fits across various treatments of strangeness conservation under different freeze-out conditions as a function of the charged particle multiplicity density . Additionally, we examine how the anti-hadron to pion yield ratios of light and strange baryons, as well as the meson, evolve within a flavour-dependent model. Through a unique two-temperature chemical freeze-out approach, we show that flavour dependence of in a Strangeness Canonical Ensemble leads to a natural explanation of strangeness enhancement from small to large systems at LHC energies without requiring any non-equilibrium particle production at small .

    Comments:
    7 pages, 5 figures, 2 tables. Submitted to and accepted by Physics Letters B
    Subjects:
    Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2109.09843 [pdf]
    PLB(2022)·23 citations
  3. 07

    [Submitted on 21 Sept 2021] (cross-list from hep-lat)

    Approaching nuclear interactions with lattice QCD

    Marc Illa🇪🇸

    Nuclei make up the majority of the visible matter in the Universe; obtaining a first principles description of the nuclear properties and interactions between nuclei directly from the underlying theory of the strong interaction, Quantum Chromodynamics (QCD), is one of the main goals of the nuclear physics community. Although the theory was established nearly fifty years ago, the complexities of QCD at low energies precludes analytical solutions of the simplest hadronic systems, let alone the features of the nuclear forces. In this thesis we follow the lattice QCD approach, according to which QCD is solved non-perturbatively in a discretized space-time via large-scale numerical calculations. Specifically, the interactions between two octet baryons, with strangeness ranging from 0 to -4, are studied at low energies with larger-than-physical quark masses, and the low-energy coefficients in pionless effective field thepry relevant for two-baryon interactions, including those responsible for SU(3) flavor-symmetry breaking, are constrained.

    Comments:
    PhD thesis, Universitat de Barcelona (September, 2021). Based on arXiv:2009.12357
    Subjects:
    High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    2109.10068 [pdf]
    1 citation
  4. 08

    [Submitted on 21 Sept 2021] (cross-list from hep-lat)

    Funny business from the large finite temperature crossover

    Thomas DeGrand🇺🇸

    It is well known that the deconfinement transition temperature for gauge theory is almost independent of , and the transition is first order for . In the real world (, light quarks) it is a crossover located far away from the pure gauge value. What happens to the transition temperature at fixed fermion mass if the number of fermion flavors is held constant () and is varied? There are multiple plausible stories, only one of which appears to be true when the systems are simulated on the lattice. I describe the physics issues which surround the question and my lattice - based answer to it.

    Comments:
    6 pages, 2 figures, contribution to Lattice 2021
    Subjects:
    High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    2109.10337 [pdf]
    PoS(2022)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE