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Nuclear Theory·nucl-th

Wednesday·November 3, 2021

8 papers—4 primary·4 cross-listed

All8Primary4Cross-lists4
  1. 01

    [Submitted on 1 Nov 2021]

    Medium modification of jet shape observables in Pb-Pb collisions at = 2.76 TeV using EPOS and JEWEL event generators

    Sumit Kumar Saha🇮🇳 · Debojit Sarkar🇺🇸 · Subhasis Chattopadhyay🇮🇳 · Ashik Ikbal Sheikh🇮🇳 · Sidharth Kumar Prasad🇮🇳

    The substructure of charged jets gets modified due to the presence of the medium in heavy-ion collisions which is an indication of redistribution of energy inside the jet cone. It helps to understand the energy loss mechanisms of jets in the medium. A model dependent study of the modification of differential jet shape and the angularity (g) due to medium, has been performed in the most central Pb-Pb collisions at 2.76 TeV in the jet range of 20-40 GeV/c.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2111.01200 [pdf]
    NPA(2021)·0 citations
  2. 02

    [Submitted on 2 Nov 2021]

    Multi-reference many-body perturbation theory for nuclei III -- Ab initio calculations at second order in PGCM-PT

    Mikael Frosini🇫🇷 · Thomas Duguet🇫🇷 · Jean-Paul Ebran🇫🇷 · Benjamin Bally🇪🇸 · Heiko Hergert🇺🇸 · Tomás R. Rodríguez🇪🇸 · Robert Roth🇩🇪 · Jiangming Yao🇹🇼 · Vittorio Somà🇫🇷

    In spite of missing dynamical correlations, the projected generator coordinate method (PGCM) was recently shown to be a suitable method to tackle the low-lying spectroscopy of complex nuclei. Still, describing absolute binding energies and reaching high accuracy eventually requires the inclusion of dynamical correlations on top of the PGCM. In this context, the present work discusses the first realistic results of a novel multi-reference perturbation theory (PGCM-PT) that can do so within a symmetry-conserving scheme for both ground and low-lying excited states. First, proof-of-principle calculations in a small () model space demonstrate that exact binding energies of closed- (\nucl{O}{16}) and open-shell (\nucl{O}{18}, \nucl{Ne}{20}) nuclei are reproduced within at second order, i.e. through PGCM-PT(2). Moreover, profiting from the pre-processing of the Hamiltonian via multi-reference in-medium similarity renormalization group transformations, PGCM-PT(2) can reach converged values within smaller model spaces than with an unevolved Hamiltonian. Doing so, dynamical correlations captured by PGCM-PT(2) are shown to bring essential corrections to low-lying excitation energies that become too dilated at leading order, i.e., at the strict PGCM level. The present work is laying the foundations for a better understanding of the optimal way to grasp static and dynamical correlations in a consistent fashion, with the aim of accurately describing ground and excited states of complex nuclei via ab initio many-body methods.

    Subjects:
    Nuclear Theory (nucl-th); Computational Physics (physics.comp-ph)
    arXiv:
    2111.01461 [pdf]
    EPJA(2022)·91 citations
  3. 03

    [Submitted on 2 Nov 2021]

    Microscopic version of the Bohr-Mottelson model and its application

    H. G. Ganev

    The shell-model coupling scheme of the proton-neutron symplectic model (PNSM), defined by the following dynamical symmetry chain , is considered. It is shown that it corresponds to a microscopic version of the Bohr-Mottelson collective model which captures the original relationships between its exactly solvable submodel limits. This variant of the PNSM provides an interesting and relevant shell-model symplectic-based framework for exploring the nuclear collective dynamics. Some simple applications of the present theory to different nuclei with various collective properties are given.

    Comments:
    11 pages, 2 figures, to appear in the Proceedings of the international workshop on Shapes and Dynamics of Atomic Nuclei: Contemporary Aspects (SDANCA21), Sofia, Bulgaria, 16-18 September 2021, ed. N. Minkov
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2111.01659 [pdf]
    Bulg.J.Phys.(2021)·2 citations
  4. 04

    [Submitted on 2 Nov 2021]

    Modification of leptonic invariant mass in ultrarelativistic heavy ion collisions as a measure of the electromagnetic field

    Yifeng Sun🇮🇹 · Vincenzo Greco🇮🇹 · Xin-Nian Wang🇺🇸

    An extraordinary strong magnetic field, Gauss, is expected to be generated in non-central ultrarelativistic heavy ion collisions and it is envisaged to induce several effects on hot QCD matter including the possibility of local parity and local parity and charge conjugation symmetry violations. A direct signature of such e.m. fields and a first quantitative measurement of its strength and lifetime are still missing. We point out that both the mean value of leptonic invariant mass of boson, reconstructed by its decaying lepton pairs, and the relative width are modified in relativistic heavy ion collisions due to the presence of strong initial e.m. fields. We propose a measurement of the leptonic invariant mass of as a novel probe of the strength of the . Both shifts could be up to about few hundred MeV and are found to depend on the integral of over the time duration quadratically (approximate). Hence it provides a novel and clear probe of electromagnetic fields, which can be tested experimentally.

    Comments:
    6 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2111.01716 [pdf]
    PLB(2022)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE