PaperPanorama
FAQ

Nuclear Theory·nucl-th

Thursday·June 20, 2019

9 papers—5 primary·4 cross-listed

All9Primary5Cross-lists4
  1. 01

    [Submitted on 18 Jun 2019]

    Critical parameters of liquid-gas phase transition in thermal symmetric and asymmetric nuclear matter

    Shen Yang · Bo Nan Zhang · Bao Yuan Sun

    The properties of critical parameters and phase diagram structure of liquid-gas phase transition are investigated in thermal symmetric and asymmetric nuclear matter with the covariant density functional (CDF) theory. Although uncertainty remains in predicting the critical parameters such as the critical temperature and pressure from various CDF functionals, several correlations are explored numerically and verified to be approximately linear between them. These correlations become worse when nuclear matter is more isospin asymmetric, resulting mainly from the effects induced by symmetry energy. By looking over the isospin dependence of the critical temperature, the role of the symmetry energy in LG transition properties of asymmetric matter is realized. The change of critical temperature with isospin asymmetry is found to be correlated well with and as a consequence could be constrained by the density slope of symmetry energy at saturation density. Then, the structure of phase diagram of thermal nuclear matter is analyzed carefully. It is revealed that the contribution from symmetry energy dominates the size of liquid-gas phase coexistence area. Moreover, the specific pattern of the phase diagram could be determined by the critical temperature at non-zero isospin asymmetry, illustrated from the correlations of the temperature with pressures at several characteristic points, paving the possible way to further explore the structure of liquid-gas phase diagram of thermal nuclear matter.

    Comments:
    12 pages, 10 figures, 4 tables
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1906.07783 [pdf]
    PRC(2019)·29 citations
  2. 02

    [Submitted on 19 Jun 2019]

    Soft breathing modes in neutron--rich nuclei with the subtracted second random--phase approximation

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

    We analyze the isoscalar response related to breathing modes with particular attention being paid to low-lying excitations in neutron--rich nuclei. We use the subtracted second random--phase approximation (SSRPA) to describe microscopically the response. By increasing the neutron excess, we study the evolution of the response in Ca isotopes going from Ca to Ca and to Ca as well as in isotones going from Ca to S and to Si. Finally, the case of Ni is investigated. We predict soft monopole modes in neutron--rich nuclei which are driven by neutron excitations. At variance with dipole pygmy modes, these neutron excitations are not only strongly dominant at the surface of the nucleus but over its entire volume. The effect of the mixing with two particle-two hole configurations induced by the SSRPA model is analyzed. The properties of such soft neutron modes are investigated in terms of their excitation energies, transition densities and wave--function components. Their collectivity is also discussed as a function of the isospin asymmetry and of the mass of the nucleus. The link between such low--energy compression modes and a compressibility modulus introduced for neutron--rich infinite matter is finally studied.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1906.07977 [pdf]
    PRC(2019)·9 citations
  3. 03

    [Submitted on 18 Jun 2019]

    Hydrodynamical response of plane correlation in Pb+Pb collisions at =2.76 TeV

    Jing Yang · Yong Zhang

    In high energy heavy-ion collisions, the final anisotropic flow coefficients and their corresponding event-plane correlations are considered as the medium evolutional response to the initial geometrical eccentricities and their corresponding participant-plane correlations. We formulate a systematic theoretical analysis to study the hydrodynamical responses concerning higher order effects in Pb+Pb collisions at TeV by using Monte Carlo Glauber (MC-Glauber) model. To further understand the transformations of the initial participant-plane correlation, we construct a new set of events which randomize the directions of the initial participant planes of the original events. Our results indicate that the final strong event-plane correlations are mainly transformed from the large initial eccentricities, rather than the strong participant-plane correlations. However, the large flow coefficients and the discrepancies between the flow coefficients calculated by the single-shot and event-by-event simulations in peripheral collisions are relevant to those strong initial participant-plane correlations.

    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Theory (hep-th)
    arXiv:
    1906.08132 [pdf]
    IJMPE(2020)·1 citation
  4. 04

    [Submitted on 19 Jun 2019]

    A Survey of Nuclear Pasta in the Intermediate Density Regime I: Shapes and Energies

    B. Schuetrumpf · G. Martínez-Pinedo · Md Afibuzzaman · H. M. Aktulga

    Background: Nuclear pasta, emerging due to the competition between the long-range Coulomb force and the short-range strong force, is believed to be present in astrophysical scenarios, such as neutron stars and core-collapse supernovae. Its structure can have a high impact e.g. on neutrino transport or the tidal deformability of neutron stars. Purpose: We study several possible pasta configurations, all of them minimal surface configurations, which are expected to appear in the mid-density regime of nuclear pasta, i.e. around 40% of the nuclear saturation density. In particular we are interested in the energy spectrum for different pasta configurations considered. Method: Employing the density functional theory (DFT) approach, we calculate the binding energy of the different configurations for three values of the proton content XP = 1/10, 1/3 and 1/2, by optimizing their periodic length. We study finite temperature effects and the impact of electron screening. Results: Nuclear pasta lowers the energy significantly compared to uniform matter, especially for . However, the different configurations have very similar binding energies. For large proton content, , the pasta configurations are very stable, for lower proton content temperatures of a few MeV are enough for the transition to uniform matter. Electron screening has a small influence on the binding energy of nuclear pasta, but increases its periodic length. Conclusion: Nuclear pasta in the mid-density regime lowers the energy of the matter for all proton fractions under study. It can survive even large temperatures of several MeV. Since various configurations have very similar energy, it is to expected that many configurations can coexist simultaneously already at small temperatures.

    Comments:
    10 pages, 11 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    1906.08155 [pdf]
    PRC(2019)·36 citations
  5. 05

    [Submitted on 19 Jun 2019]

    Low-energy neutrino scattering in experiment and astrophysics

    Natalie Jachowicz🇧🇪 · Nils Van Dessel🇧🇪 · Alexis Nikolakopoulos🇧🇪

    We review the relevance of neutrino-nucleus interactions at energy transfers below 100 MeV for accelerator-based experiments, experiments at lower energies and for astrophysical neutrinos. The impact of low-energy scattering processes in the energy reconstruction analysis of oscillation experiments is investigated. We discuss the modeling of coherent scattering processes and compare its strength to that of inelastic interactions. The presented results are obtained within a continuum random phase approximation approach.

    Comments:
    Accepted for publication in J. Phys. G
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1906.08191 [pdf]
    J.Phys.G(2019)·18 citations

Affiliations

first authorsco-authorsvia INSPIRE