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Nuclear Theory·nucl-th

Friday·January 18, 2019

14 papers—6 primary·8 cross-listed

All14Primary6Cross-lists8
  1. 01

    [Submitted on 16 Jan 2019]

    A Study of Charge Radii and Neutron Skin Thickness near Nuclear Drip Lines

    Virender Thakur · Shashi K Dhiman

    We studied the charge radius, rms radius and neutron skin thickness in even-even isotopes of Si, S, Ar and Ca and isotones of N =20, 28, 50 and 82. The in doubly-magic Ca, Ni, Sn and Pb nuclei has also been calculated. Theoretical calculations are done with the Hartree-Fock-Bogoliubov theory with the effective Skyrme interactions. Calculated theoretical estimates are in good agreement with the recently available experimental data. The charge radii for Si, S, Ar and Ca isotopes is observed to be minimum at neutron number N =14. The theoretically computed results with UNEDF0 model parameterization of functional are reasonably reproducing the experimental data for in Ca, Ni and Sn. The energy density functional of UNEDF1 model provides much improved result of for Pb.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1901.05453 [pdf]
    NPA(2019)·13 citations
  2. 02

    [Submitted on 16 Jan 2019]

    Optimizing the relativistic energy density functional with nuclear ground state and collective excitation properties

    E. Yuksel · T. Marketin · N. Paar

    We introduce a new relativistic energy density functional constrained by the ground state properties of atomic nuclei along with the isoscalar giant monopole resonance energy and dipole polarizability in Pb. A unified framework of the relativistic Hartree-Bogoliubov model and random phase approximation based on the relativistic density-dependent point coupling interaction is established in order to determine the DD-PCX parameterization by minimization. This procedure is supplemented with the co-variance analysis in order to estimate statistical uncertainties in the model parameters and observables. The effective interaction DD-PCX accurately describes the nuclear ground state properties including the neutron-skin thickness, as well as the isoscalar giant monopole resonance excitation energies and dipole polarizabilities. The implementation of the experimental data on nuclear excitations allows constraining the symmetry energy close to the saturation density, and the incompressibility of nuclear matter by using genuine observables on finite nuclei in the minimization protocol, rather than using pseudo-observables on the nuclear matter, or by relying on the ground state properties only, as it has been customary in the previous studies.

    Comments:
    6 pages, 3 figures, submitted to Physical Review C
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1901.05552 [pdf]
    PRC(2019)·81 citations
  3. 03

    [Submitted on 17 Jan 2019]

    New self-consistent mean field approximation and its application in strong interaction phase transition

    Fei Wang🇨🇳 · Yakun Cao🇨🇳 · Yonghui Dia · Hongshi Zong🇨🇳

    In this letter, taking the Nambu--Jona--Lasinio model as an example, we propose a new self-consistent mean field approximation method by means of Fierz transformation. This new self-consistent mean field approximation introduces a new free parameter to be determined by experiments and when takes 0.5, it reduces to the mean field approximation that was commonly used in the past. Then based on this self-consistent mean field approximation, we study the influence of the undetermined parameter on the phase diagram of the two-flavor strong interaction matter. It is found that the value of plays an extremely important role in the study of strong interaction phase diagram. It not only changes the position of the phase transition point of strong interaction matter, but also affects the order of phase transition, for example, when is greater than the critical value , then the strong interaction matter phase diagram no longer exists critical end point. In addition, in the case of zero temperature and finite density, we also found that when is greater than 1.044, the pseudo-critical chemical potential is about 45 times the saturation density of the nuclear matter, which agrees with the expected results from the image of hadrons degree of freedom. The resulting equations of state of strong interaction matter at low temperatures and high densities will have an important impact on the study of the mass radius relationship of neutron stars and the merging process of binary neutron stars.

    Comments:
    5 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1901.05601 [pdf]
    CPC(2019)·29 citations
  4. 04

    [Submitted on 17 Jan 2019]

    Unified Coupled-Channels and Hauser-Feshbach Model Calculation for Nuclear Data Evaluation

    Toshihiko Kawano🇺🇸

    We present an overview of the coupled-channels optical model and the Hauser-Feshbach theory code CoH, which focuses on the nuclear reaction calculations in the keV to tens of MeV region with special attention to the nuclear deformation. The code consists of three major sections that undertake the one-body potential mean-field theory, the coupled-channels optical model, and the Hauser-Feshbach statistical decay. There are other complementary segments to perform the whole nuclear reaction calculations, such as the direct/semidirect radiative capture process, pre-equilibrium process, and prompt fission neutron emission.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1901.05641 [pdf]
    20 citations
  5. 05

    [Submitted on 17 Jan 2019]

    Computation of products of phase space factors and nuclear matrix elements for the Double Beta Decay

    Sabin Stoica🇷🇴

    The nuclear matrix elements (NME) and phase space factors (PSF) entering the half-life formulas of the double-beta decay (DBD) process are two key quantities whose accurate computation still represents a challenge. In this paper we propose a new approach of calculating them, namely to compute directly their product as an unique formula. This procedure allows a more coherent treatment of the nuclear approximations and input parameters appearing in both quantities and avoids possible confusion in interpreting the DBD data due to different individual expressions adopted for PSF and NME (and consequently their reporting in different units) by different authors. Our calculations are performed for both two neutrino () and neutrinoless () decay modes, and for five nuclei of most experimental interest. Further, using the most recent experimental limits for decay half-lives, we provide new constraints on the light mass neutrino parameter. Finally, by separating in the half-lives formulas the factor representing the axial-vector constant to the forth, we advance suggestions on how to reduce the errors introduced in calculation by the uncertain value of this constant by exploiting the DBD data from different isotopes and/or decay modes.

    Comments:
    6 pages, 2 tables, accepted at Chinese Physics C
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1901.05718 [pdf]
    CPC(2019)·4 citations
  6. 06

    [Submitted on 17 Jan 2019]

    Structural properties and decay modes of Z 122, 120 and 118 superheavy nuclei

    G. Saxena · M. Kumawat · S. Somorendro Singh · Mamta Aggarwal

    Structural properties and the decay modes of the superheavy elements Z 122, 120, 118 are studied in a microscopic framework. We evaluate the binding energy, one- and two- proton and neutron separation energy, shell correction and density profile of even and odd isotopes of Z 122, 120, 118 (284 A 352) which show a reasonable match with FRDM results and the available experimental data. Equillibrium shape and deformation of the superheavy region are predicted. We investigate the possible decay modes of this region specifically -decay, spontaneous fission (SF) and the -decay and evaluate the probable -decay chains. The phenomena of bubble like structure in the charge density is predicted in 122, 120 and 118 with significant depletion fraction around 20-24 which increases with increasing Coulomb energy and diminishes with increasing isospin (NZ) values exhibiting the fact that the coloumb forces are the main driving force in the central depletion in superheavy systems.

    Comments:
    18 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1901.05926 [pdf]
    IJMPE(2019)·18 citations

Affiliations

first authorsco-authorsvia INSPIRE