PaperPanorama

Nuclear Theory·nucl-th

Monday·November 14, 2022

8 papers3 primary·5 cross-listed

  1. 01

    [Submitted on 10 Nov 2022]

    Toward a description of the centrality dependence of the charge balance function in the HYDJET++ model

    A.S. Chernyshov🇷🇺 · G.Kh. Eyyubova🇷🇺 · V.L. Korotkikh🇷🇺 · I.P. Lokhtin🇷🇺 · L.V. Malinina🇷🇺 · S.V. Petrushanko🇷🇺 · A.M. Snigirev🇷🇺 · E.E. Zabrodin🇷🇺

    Data from the Large Hadron Collider on the charge balance function in Pb+Pb collisions at center-of-mass energy 2.76~TeV per nucleon pair are analyzed and interpreted within the framework of the \hydjet++ model. This model allows us to qualitatively reproduce the experimentally observed centrality dependence of the balance function widths at relatively low transverse momentum intervals due to the different charge creation mechanisms in soft and hard processes. However, a fully adequate description of the balance function in these intervals implies an essential modification of the model by including exact charge conservation via the canonical rather than the grand canonical ensemble. A procedure is proposed for introducing charge correlations into the thermal model without changing other model parameters. With increasing transverse momenta, the default model results describe the experimental data much better because the contribution of the soft component of the model is significantly reduced in these transverse momentum intervals. In practical terms, there is a transition to a single source of charge correlations, namely, charge correlations in jets in which exact charge conservation holds at each stage.

    Comments:
    Matches published version
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2211.05874 [pdf]
    CPC(2023)·8 citations
  2. 02

    [Submitted on 11 Nov 2022]

    An introduction to computational complexity and statistical learning theory applied to nuclear models

    Andrea Idini

    The fact that we can build models from data, and therefore refine our models with more data from experiments, is usually given for granted in scientific inquiry. However, how much information can we extract, and how precise can we expect our learned model to be, if we have only a finite amount of data at our disposal? Nuclear physics demands an high degree of precision from models that are inferred from the limited number of nuclei that can be possibly made in the laboratories. In manuscript I will introduce some concepts of computational science, such as statistical theory of learning and Hamiltonian complexity, and use them to contextualise the results concerning the amount of data necessary to extrapolate a mass model to a given precision.

    Comments:
    6 pages, 1 figure, proceeding INPC 2022, Cape Town, South Africa
    Subjects:
    Nuclear Theory (nucl-th); Machine Learning (cs.LG)
    arXiv:
    2211.06182 [pdf]
    J.Phys.Conf.Ser.(2023)·1 citation
  3. 03

    [Submitted on 11 Nov 2022]

    Perspectives on few-body cluster structures in exotic nuclei

    D. Bazin · K. Becker · F. Bonaiti · Ch. Elster · K. Fossez · T. Frederico · A. Gnech · C. Hebborn · M. Higgins · L. Hlophe · B. Kay · S. König and 7 other authors

    It is a fascinating phenomenon in nuclear physics that states with a pronounced few-body structure can emerge from the complex dynamics of many nucleons. Such halo or cluster states often appear near the boundaries of nuclear stability. As such, they are an important part of the experimental program beginning at the Facility for Rare Isotope Beams (FRIB). A concerted effort of theory and experiment is necessary both to analyze experiments involving effective few-body states, as well as to constrain and refine theories of the nuclear force in light of new data from these experiments. As a contribution to exactly this effort, this paper compiles a collection of ``perspectives'' that emerged out of the Topical Program ``Few-body cluster structures in exotic nuclei and their role in FRIB experiments'' that was held at FRIB in August 2022 and brought together theorists and experimentalists working on this topic.

    Comments:
    This version should match the published one
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2211.06281 [pdf]
    Few Body Syst.(2023)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE