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Nuclear Theory·nucl-th

Thursday·November 19, 2020

4 papers—1 primary·3 cross-listed

All4Primary1Cross-lists3
  1. 02

    [Submitted on 17 Nov 2020] (cross-list from hep-ph)

    Tsallis statistics, fractals and QCD

    Airton Deppman🇧🇷 · Eugenio Megias🇪🇸 · Debora P. Menezes🇧🇷

    We study the non-extensive Tsallis statistics and its applications to QCD and high energy physics, and analyze the possible connections of this statistics with a fractal structure of hadrons. Then, we describe how scaling properties of Yang-Mills theories allow the appearance of self-similar structures in gauge fields, which actually behave as fractals. The Tsallis entropic index, , is deduced in terms of the field theory parameters, resulting in a good agreement with the value obtained experimentally.

    Comments:
    6 pages, 4 figures. Talk given by E.Megias at the 23th International Conference in Quantum Chromodynamics (QCD 20), Montpellier, France, 27 - 30 October 2020. arXiv admin note: text overlap with arXiv:2002.12667
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    2011.09134 [pdf]
    Nucl.Part.Phys.Proc.(2021)·4 citations
  2. 03

    [Submitted on 18 Nov 2020] (cross-list from astro-ph.HE)

    Heat release in accreting neutron stars

    Mikhail E. Gusakov · Andrey I. Chugunov

    Observed thermal emission from accreting neutron stars (NSs) in a quiescent state is believed to be powered by nonequilibrium nuclear reactions that heat the stellar crust (deep crustal heating paradigm). We derive a simple universal formula for the heating efficiency, assuming that an NS has a fully accreted crust. We further show that, within the recently proposed thermodynamically consistent approach to the accreted crust, the heat release can be parametrized by the only one parameter -- the pressure at the outer-inner crust interface (as we argue, this pressure should not necessarily coincide with the neutron-drip pressure). We discuss possible values of for a selection of nuclear models that account for shell effects, and determine the net heat release and its distribution in the crust as a function of . We conclude that the heat release should be reduced by a factor of few in comparison to previous works.

    Comments:
    5 pages, 1 figure, 1 table + 5 pages supplemental material
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    2011.09354 [pdf]
    PRD(2021)·26 citations
  3. 04

    [Submitted on 18 Nov 2020] (cross-list from hep-th)

    Zilch Vortical Effect for Fermions

    Artem Alexandrov🇷🇺 · Pavel Mitkin🇷🇺

    We consider the notion of zilch current that was recently discussed in the literature as an alternative helicity measure for photons. Developing this idea, we suggest the generalization of the zilch for the systems of fermions. We start with the definition of the photonic zilch current in chiral kinetic theory framework and work out field-theoretical definition of the fermionic zilch using the Wigner function formalism. This object has similar properties to the photonic zilch and is conserved in the non-interacting theory. We also show that, in full analogy with a case of photons, the fermionic zilch acquires a non-trivial contribution due to the medium rotation - zilch vortical effect (ZVE) for fermions. Combined with a previously studied ZVE for photons, these results form a wider set of chiral effects parameterized by the spin of the particles and the spin of the current. We briefly discuss the origin of the ZVE, its possible relation to the anomalies in the underlying microscopic theory and possible application for studying the spin polarization in chiral media.

    Comments:
    13 pages
    Subjects:
    High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2011.09429 [pdf]
    JHEP(2021)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE