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Nuclear Theory·nucl-th

Tuesday·June 15, 2021

10 papers—7 primary·3 cross-listed

All10Primary7Cross-lists3
  1. 08

    [Submitted on 11 Jun 2021] (cross-list from nucl-ex)

    Expanding Nuclear Physics Horizons with the Gamma Factory

    Dmitry Budker🇩🇪 · Julian C. Berengut🇦🇺 · Victor V. Flambaum🇦🇺 · Mikhail Gorchtein🇩🇪 · Junlan Jin🇨🇳 · Felix Karbstein🇩🇪 · Mieczyslaw Witold Krasny🇫🇷 · Yuri A. Litvinov🇩🇪 · Adriana Pálffy🇩🇪 · Vladimir Pascalutsa🇩🇪 · Alexey Petrenko🇷🇺 · Andrey Surzhykov🇩🇪 and 4 other authors

    The Gamma Factory (GF) is an ambitious proposal, currently explored within the CERN Physics Beyond Colliders program, for a source of photons with energies up to MeV and photon fluxes (up to photons per second) exceeding those of the currently available gamma sources by orders of magnitude. The high-energy (secondary) photons are produced via resonant scattering of the primary laser photons by highly relativistic partially-stripped ions circulating in the accelerator. The secondary photons are emitted in a narrow cone and the energy of the beam can be monochromatized, eventually down to the ppm level, via collimation, at the expense of the photon flux. This paper surveys the new opportunities that may be afforded by the GF in nuclear physics and related fields.

    Comments:
    69 pages, 13 tables, 33 figures
    Subjects:
    Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th); Accelerator Physics (physics.acc-ph); Atomic Physics (physics.atom-ph)
    arXiv:
    2106.06584 [pdf]
    Annalen Phys.(2022)·42 citations
  2. 09

    [Submitted on 12 Jun 2021] (cross-list from hep-ph)

    Perspective on Tsallis Statistics for Nuclear and Particle Physics

    Joseph I. Kapusta🇺🇸

    This is a concise introduction to the topic of nonextensive Tsallis statistics meant especially for those interested in its relation to high energy proton-proton, proton-nucleus, and nucleus-nucleus collisions. The three types of Tsallis statistics are reviewed. Only one of them is consistent with the fundamental hypothesis of equilibrium statistical mechanics. The single particle distributions associated with it, namely Boltzmann, Fermi-Dirac, and Bose-Einstein, are derived. These are not equilibrium solutions to the conventional Boltzmann transport equation which must be modified in a rather nonintuitive manner for them to be so. Nevertheless the Boltzmann limit of the Tsallis distribution is extremely efficient in representing a wide variety of single particle distributions in high energy proton-proton, proton-nucleus, and nucleus-nucleus collisions with only three parameters, one of them being the so-called nonextensitivity parameter . This distribution interpolates between an exponential at low transverse energy, reflecting thermal equilibrium, to a power law at high transverse energy, reflecting the asymptotic freedom of QCD. It should not be viewed as a fundamental new parameter representing nonextensive behavior in these collisions.

    Comments:
    13 pages, 1 figure
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2106.06824 [pdf]
    IJMPE(2021)·15 citations
  3. 10

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

    Fully heavy multiquarks

    Jean-Marc Richard🇫🇷

    The existence of stable multiquarks made of heavy quarks and antiquarks is discussed in the framework of potential models. It is stressed that the few-body problem should be handled seriously and accurately. No bound state is found within the current models. But resonances are likely present in the spectrum above the lowest threshold.

    Comments:
    Contribution to the 8th Asian-Pacific Few-Body Conference, Kanazawa (Japan), March 2021, to appear in a special issue of Few-Body Systems
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2106.07434 [pdf]
    Few Body Syst.(2021)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE