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Nuclear Theory·nucl-th

Thursday·July 12, 2018

11 papers—5 primary·6 cross-listed

All11Primary5Cross-lists6
  1. 01

    [Submitted on 11 Jul 2018]

    Better insight into the Strutinsky method (published version)

    B. Mohammed-Azizi🇩🇿

    Strutinsky's method is reviewed through a new understanding. This method depends on two free parameters: The smoothing parameter and the order of the curvature correction. It turns out that this method is nothing but a compromise between two fundamental conditions which are the so-called asymptotic limit which comes from the so-called remainder which imposes a small as possible smoothing parameter and the smoothing condition which forces that parameter to be, at least, slightly larger than the inter shell spacing. In this paper, to find the best value of the smoothing parameter, a new criterion is proposed instead of the plateau condition . This new criterion is much more clear and free from ambiguities of the usual plateau condition. It is also found, that the second free parameter, i.e., the order of the curvature correction, plays an accessory role since, it is connected intimately to the smoothing parameter, when the smoothing is realized. This paper provides a new and definitive insight into Strutinsky's method and its relationship with semi-classical methods.

    Comments:
    16 pages, 4 Figures, 3 Tables
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1807.04006 [pdf]
    PRC(2019)·4 citations
  2. 02

    [Submitted on 11 Jul 2018]

    Consolidating the concept of low-energy magnetic dipole decay radiation

    J. E. Midtbø · A. C. Larsen · T. Renstrøm · F. L. Bello Garrote · E. Lima

    We have made a thorough study of the low-energy behaviour of the -ray strength function within the framework of the shell model. We have performed large-scale calculations spanning isotopic and isotonic chains over several mass regions, with the purpose of studying the systematic behavior of the low-energy enhancement (LEE) for transitions. There are clear trends in the calculations: From being all but absent in the lowest mass region, the LEE becomes steeper and more pronounced as the mass number increases, and for a given mass region it further increases towards shell closures. Moreover, the LEE is found to be steeper in regions near doubly-magic nuclei where proton particles couple to neutron holes. These trends enable us to consolidate several previous works on the LEE into a single, consistent concept. We compare the inferred trends to the available experimental data from the Oslo method, and find suppport for the systematic behaviour. Lastly we have compared the calculations to strength functions compiled from discrete, experimental lifetimes, and find excellent agreement; the discrete data are consistent with a LEE, and indicate that the slope varies as function of mass number.

    Comments:
    11 pages, 13 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1807.04036 [pdf]
    PRC(2018)·43 citations
  3. 03

    [Submitted on 11 Jul 2018]

    Beyond--mean--field effective masses in the nuclear Fermi liquid from axial breathing modes

    M. Grasso🇫🇷 · D. Gambacurta🇷🇴 · O. Vasseur🇫🇷

    Axial breathing modes are studied within the nuclear energy--density--functional theory to discuss the modification of the nucleon effective mass produced beyond the mean--field approximation. This analysis is peformed with the subtracted second random--phase--approximation (SSRPA) model applied to two nuclei, Ca and Zr. Analyzing the centroid energies of axial breathing modes obtained with the mean--field--based random--phase approximation and with the beyond--mean--field SSRPA model, we estimate the modification (enhancement) of the effective mass which is induced beyond the mean field. This is done by employing a relation, obtained with the Landau's Fermi liquid theory, between the excitation frequency of axial modes to , where () is the bare (effective) mass. Such an enhancement of the effective mass is discussed in connection with the renormalization of single--particle excitation energies generated by the energy--dependent SSRPA self-energy correction. We find that the effective beyond--mean--field compression of the single--particle spectrum produced by the self--energy correction is coherent with the increase of the effective mass estimated from the analysis of axial breathing modes.

    Comments:
    5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1807.04039 [pdf]
    PRC(2018)·12 citations
  4. 04

    [Submitted on 11 Jul 2018]

    Transport phenomena with chiral fermions in strong magnetic fields

    Koichi Hattori🇨🇳

    I discuss the electrical conductivity, bulk viscosity, and heavy-quark diffusion coefficient in strong magnetic fields putting emphasis on consequences of the chirality conservation on the perturbative relaxation dynamics.

    Comments:
    Prepared for the proceedings of Quark Matter 2018 in Venice
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1807.04150 [pdf]
    NPA(2019)·2 citations
  5. 05

    [Submitted on 11 Jul 2018]

    Viscous hydrodynamics for nonconformal anisotropic fluids

    Mike McNelis🇺🇸 · Dennis Bazow🇺🇸 · Ulrich Heinz🇺🇸

    A new formulation of (3+1)-dimensional anisotropic hydrodynamics is presented that accounts nonperturbatively for the large longitudinal-transverse pressure anisotropy and bulk viscous pressure in heavy-ion collisions. The initialization of the anisotropic hydrodynamic stage is discussed, and a comparison to standard viscous hydrodynamics for (0+1)- dimensional Bjorken expansion is presented.

    Comments:
    4 pages, 3 figures, Quark Matter 2018
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1807.04223 [pdf]
    NPA(2019)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE