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Nuclear Theory·nucl-th

Wednesday·October 27, 2021

11 papers—6 primary·5 cross-listed

All11Primary6Cross-lists5
  1. 01

    [Submitted on 25 Oct 2021]

    Predictions and postdictions for relativistic lead and oxygen collisions with Trajectum

    Govert Nijs🇺🇸 · Wilke van der Schee🇨🇭

    We introduce a global analysis of relativistic heavy ion collisions using Trajectum of a significantly higher precision and including a new option to vary the normalization of the centrality estimator. We use the posterior distribution of our parameters to generate a set of high statistics samples that allows us to make precise predictions including statistical and systematic uncertainties estimated from the model parameter distribution. The results are systematically compared with experiment whereby we also include many observables not included in the global analysis. This includes in particular (extremely) ultracentral anisotropic flow and mean transverse momentum, whereby we find satisfactory agreement with experiment where data is available. Lastly, we compute spectra and anisotropic flow for oxygen-oxygen collisions performed at RHIC and to be performed at the LHC and comment on how these collisions may inform us on properties of the Quark-Gluon-Plasma.

    Comments:
    19 pages and 18 figures. The Trajectum code can be found at https://sites.google.com/view/govertnijs/trajectum
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2110.13153 [pdf]
    PRC(2022)·79 citations
  2. 02

    [Submitted on 26 Oct 2021]

    Intermittency analysis in relativistic heavy-ion collisions

    Zhiming Li🇨🇳 · Jin Wu🇨🇳

    Local density fluctuations near the QCD critical point can be probed by an intermittency analysis of power-law behavior on scaled factorial moments in relativistic heavy-ion collisions. We study the second-order scaled factorial moment in Au + Au collisions at = 7.7-200 GeV from the UrQMD model. Since the background subtraction and efficiency correction are two important aspects in this measurement, we propose a cumulative variable method to remove background contribution and a cell-by-cell method for efficiency correction in the intermittency analysis.

    Comments:
    5 pages, 3 figures, contribution to ISMD2021 12-16 July 2021, modified according to the journal requirement
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2110.13394 [pdf]
    SciPost Phys.Proc.(2022)·0 citations
  3. 03

    [Submitted on 26 Oct 2021]

    Shell-model study for GT-strengths corresponding to decay of Ge and Ge

    Vikas Kumar · Anil Kumar · Praveen C. Srivastava

    In the present work, we have reported a comprehensive shell-model study of GT-strengths for recently available experimental data for Ga and Ga from RIKEN Nishina Center [Phys. Rev. C 103, 014324 (2021)] populated by decay of the Ge and Ge, respectively. We have performed shell-model calculations in two different model spaces, the first set of calculations in the model space using KB3G and GXPF1A interactions, while the second set in model space using JUN45 and jj44b effective interactions. Our shell-model results in model space are in a reasonable agreement with the available experimental data.

    Comments:
    16 pages, 5 figures, Accepted in Nuclear Physics A
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2110.13457 [pdf]
    NPA(2022)·7 citations
  4. 04

    [Submitted on 26 Oct 2021]

    Vorticity and polarization in the microscopic transport model PACIAE

    Anke Lei🇨🇳 · Dujuan Wang🇨🇳 · Dai-Mei zhou🇨🇳 · Ben-Hao Sa🇨🇳 · Laszlo Pal Csernai🇩🇪

    We study the behavior of four types of vorticities in non-central Au+Au collisions at energies = 5--200 GeV using a microscopic transport model PACIAE. The results show that the vorticities decay faster at lower energy and smaller impact parameter. The non-monotonic dependence of the initial vorticities on the collision energies is reconfirmed and the turning point is 10-15 GeV for different vorticities. The global polarization at energies = 7.7--200 GeV is reproduced by introducing an energy density freeze-out criterion.

    Comments:
    7 pages, 7 figures, to be published in Pyhysical Review C
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2110.13485 [pdf]
    PRC(2021)·24 citations
  5. 05

    [Submitted on 26 Oct 2021]

    Comment on Effective-range function methods for charged particle collisions

    Orlov Yu. V

    The authors of a recent paper [Phys. Rev. C 97(2018) 044003] (Ref. [1]), D. Gaspard and J.-M. Sparenberg, attempt to consider an alternative method for the asymptotic normalization coefficients (ANC) calculating which differs from so-called approximate \Delta method proposed earlier [Phys. Rev. C 96(2017) 034601] (Ref. [2]) by O.L. Ramírez Suárez, and J. M. Sparenberg. The abstract in Ref. [1], in essence, declares that the approximation used in Ref. [2], where a \Delta_l function is introduced to fit the Coulomb-nuclear phase shifts {\delta}_l^{(cs)} at low energies, is not correct, since this \Delta_l function is not analytical at zero energy. In my view, this statement is erroneous. I believe that the origin of this mistake in Ref. [1] is due to adopting the re-normalized scattering amplitude form designed for resonant states, which is not valid for a bound state. It is shown in the fundamental work [Nucl. Phys. B 60 (1973) 443] Ref.[3] by Hamilton et al. that an effective-range function (ERF) K_l(k^2) is a meromorphic in the physical sheet except for the poles of bound states on the imaginary positive axis of the momentum complex plane. In my paper [Nucl. Phys A, 1010 (2021) 122174] Ref. [4], a strict form of the re-normalized scattering amplitude is derived, which can be used for the analytical continuation to a bound state pole. It is found in Ref. 4 that the \Delta_l function has analytical properties similar to those of the K_l(k^2) function. Thus, both functions have no singularities at zero energy.

    Comments:
    3 pages
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2110.13496 [pdf]
    0 citations
  6. 06

    [Submitted on 26 Oct 2021]

    Neutron Stars and Gravitational Waves: the Key Role of Nuclear Equation of State

    P.S. Koliogiannis · A. Kanakis-Pegios · Ch.C. Moustakidis

    Neutron stars are the densest known objects in the universe and an ideal laboratory for the strange physics of super-condensed matter. Theoretical studies in connection with recent observational data of isolated neutron stars, as well as binary neutron stars systems, offer an excellent opportunity to provide robust solutions on the dense nuclear problem. In the present work, we review recent studies concerning the applications of various theoretical nuclear models on a few recent observations of binary neutron stars or neutron-star--black-hole systems. In particular, using a simple and well-established model, we parametrize the stiffness of the equation of state with the help of the speed of sound. Moreover, in comparison to the recent observations of two events by LIGO/VIRGO collaboration, GW170817 and GW190425, we suggest possible robust constraints. We also concentrate our theoretical study on the resent observation of a compact object with mass~ (GW190814 event), as a component of a system where the main companion was a black hole with mass . There is scientific debate concerning the identification of the low mass component, as it falls into the neutron-star--black-hole mass gap. This is an important issue since understanding the nature of GW190814 event will offer rich information concerning the upper limit of the speed of sound in dense matter and the possible phase transition into other degrees of freedom. We systematically study the tidal deformability of a possible high-mass candidate existing as an individual star or as a component in a binary neutron star system. Finally, we provide some applications of equations of state of hot, dense nuclear matter in hot neutron stars, protoneutron stars, and binary neutron star merger remnants.

    Comments:
    review article: 42 pages, 16 figures, 5 tables; accepted to be published in Foundations. v2: changes to match the published review article
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    2110.13557 [pdf]
    Foundations(2021)·13 citations

Affiliations

first authorsco-authorsvia INSPIRE