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Nuclear Theory·nucl-th

Thursday·September 10, 2020

11 papers—3 primary·8 cross-listed

All11Primary3Cross-lists8
  1. 01

    [Submitted on 9 Sept 2020]

    Triaxial projected shell model study of -bands in atomic nuclei

    S. Jehangir · G.H. Bhat · J.A. Sheikh · S. Frauendorf · W. Li · R. Palit

    A systematic study of -bands observed in atomic nuclei is performed using the triaxial projected shell model (TPSM) approach. The staggering phase between the even and odd spin members of the -band for most the nuclei investigated in the present work is found to have even-I-below-odd-I, which in the framework of the collective model is considered as a signature of -softness. It is observed that out of twenty-three systems studied, only four nuclei, namely, Ge, Ru, Er and Th depict staggering phase with odd-I-below-even-I, which is regarded as an indication of the static -deformation in the collective model picture. The inclusion of the quasiparticle excitations in the framework of configuration mixing is shown to reverse the staggering phase from odd-I-down to the even-I-down for all the studied nuclei, except for the aforementioned four nuclei. Furthermore, by fitting a collective Bohr Hamiltonian to the TPSM energies, the differences between the two models are delineated through a comparison of the transition probabilities.

    Comments:
    12 pages, 15 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2009.04135 [pdf]
    EPJA(2021)·39 citations
  2. 02

    [Submitted on 9 Sept 2020]

    Minimal complete sets for two pseudoscalar meson photoproduction

    Philipp Kroenert🇩🇪 · Yannick Wunderlich🇩🇪 · Farah Afzal🇩🇪 · Annika Thiel🇩🇪

    For photoproduction reactions with final states consisting of two pseudoscalar mesons and a spin-1/2 baryon, 8 complex amplitudes need to be determined uniquely. A modified version of Moravcsik's theorem is employed for these reactions, resulting in slightly over-complete sets of polarization observables that are able to determine the amplitudes uniquely. Further steps were taken to reduce the found sets to minimal complete sets. As a final result, multiple minimal complete sets without any remaining ambiguities are presented for the first time. These sets consist of observables, containing only one triple polarization observable.

    Comments:
    updated supplementary material
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2009.04356 [pdf]
    PRC(2021)·12 citations
  3. 03

    [Submitted on 9 Sept 2020]

    Photon-jet correlations in p-p and Pb-Pb collisions using JETSCAPE framework

    C. Sirimanna · A. Angerami · S. A. Bass · S. Cao · Y. Chen · J. Coleman · L. Cunqueiro · T. Dai · L. Du · R. Ehlers · H. Elfner · D. Everett and 38 other authors

    It is now well established that jet modification is a multistage effect; hence a single model alone cannot describe all facets of jet modification. The JETSCAPE framework is a multistage framework that uses several modules to simulate different stages of jet propagation through the QGP medium. These simulations require a set of parameters to ensure a smooth transition between stages. We fine tune these parameters to successfully describe a variety of observables, such as the nuclear modification factors of leading hadrons and jets, jet shape, and jet fragmentation function. Photons can be produced in the hard scattering or as radiation from quarks inside jets. In this work, we study photon-jet transverse momentum imbalance and azimuthal correlation for both and collision systems. All the photons produced in each event, including the photons from hard scattering, radiation from the parton shower, and radiation from hadronization are considered with an isolation cut to directly compare with experimental data. The simulations are conducted using the same set of tuned parameters as used for the jet analysis. No new parameters are introduced or tuned. We demonstrate a significantly improved agreement with photons from collisions compared to prior efforts. This work provides an independent, parameter free verification of the multistage evolution framework.

    Comments:
    4 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2009.04407 [pdf]
    PoS(2021)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE