Nuclear Theory·nucl-th

Monday·June 21, 2021

6 papers—4 primary·2 cross-listed

01
[Submitted on 17 Jun 2021]
Statistical Multifragmentation Model Within the Extended Morphological Thermodynamics Approach
V. S. Kucherenko · K. A. Bugaev · V. Sagun · O. Ivanytskyi
On the basis of morphological thermodynamics we develop an exactly solvable version of statistical mutifragmentation model for the nuclear liquid-gas phase transition. It is shown that the hard-core repulsion between spherical nuclei generates only the bulk (volume), surface and curvature parts of the free energy of the nucleus, while the Gaussian curvature one does not appear in the derivation. The phase diagram of nuclear liquid-gas phase transition is studied for a truncated version of the developed model.
Comments:
Talk was given at XIX Igor Sikorsky Kyiv Polytechnic Institute Conference "Theoretical and Practical Problems of Physics, Mathematics and Informatics", May 13-14, 2021, Kyiv, Ukraine (6 pages, 2 figures)
Subjects:
Nuclear Theory (nucl-th); Statistical Mechanics (cond-mat.stat-mech)
arXiv:
2106.09838 [pdf]
Ukr.J.Phys.(2022)·0 citations
02
[Submitted on 18 Jun 2021]
Decoding the Density Dependence of the Nuclear Symmetry Energy
W. G. Lynch · M. B. Tsang
The large imbalance in the neutron and proton densities in very neutron rich systems increases the nuclear symmetry energy so that it governs many aspects of neutron stars and their mergers. Extracting the density dependence of the symmetry energy therefore constitutes an important scientific objective. Many analyses have been limited to extracting values for the symmetry energy, $S_{0}$ , and its ``derivative'', $L$ , at saturation density $ρ_{0} \approx 2.6 \times 1 0^{14} g/c m^{3}$ $\approx 0.16 nucleons/f m^{3}$ , resulting in constraints that appear contradictory. We show that most experimental observables actually probe the symmetry energy at densities far from $ρ_{0}$ , making the extracted values of $S_{0}$ or $L$ imprecise. By focusing on the densities these observables actually probe, we obtain a detailed picture of the density dependence of the symmetry energy from $0.25 ρ_{0}$ to $1.5 ρ_{0}$ . From this experimentally derived density functional, we extract $L_{01} = 53.1 \pm 6.1 M e V$ at $ρ \approx 0.10 f m^{- 3}$ , a neutron skin thickness for $^{208} P b$ of $R_{n p} =$ $0.23 \pm 0.04$ fm, a symmetry pressure at saturation density of $P_{0} = 3.2 \pm 1.2 M e V / f m^{3}$ and suggests a radius for a 1.4 solar mass neutron star of $13.1 \pm 0.6$ km.
Comments:
6 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex)
arXiv:
2106.10119 [pdf]
PLB(2022)·81 citations
03
[Submitted on 18 Jun 2021]
Study of neutrino-nucleus reactions with CRISP Program (0 < $E_{ν}$ < 3 GeV)
R. Perez🇧🇷 · A. Deppman🇧🇷 · Evandro Andrade-II🇧🇷 · A.R. Samana🇧🇷 · F.G. Velasco🇧🇷 · F. Guzmán🇨🇺
The neutrino-nucleus reactions are studied at energies from 0 to 3 GeV, using the CRISP program. To simulate these reactions, CRISP uses the Monte Carlo method through an intranuclear cascade model. Quase-elastic and baryonic resonance formation channels for the neutrino-nucleon interaction are considered. The total and differential particle emission cross-sections were obtained, obtaining a good agreement with the values reported by the MiniBooNE experiment. The influence of nuclear effects on the studied reactions, such as fermionic motion, the Pauli blocking mechanism, and the nucleonic separation energy, was shown. It was not possible to simultaneously reproduce the $ν_{μ} + D$ and $ν_{μ} +^{12} C$ reactions using the same axial mass value. For the charged current quasi-elastic channel, $M_{A} = 0.95 G e V$ for the $ν_{μ} + D$ reaction, and $M_{A} = 1.35 G e V$ for the $ν_{μ} +^{12} C$ reaction. This can be solved if one considers, in addition to the neutrino-nucleon interaction, the neutrino interaction with a pair of nucleons, just as we demonstrate in the last part of this work.
Comments:
21 pages, 22 figures, 2 tables
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2106.10244 [pdf]
PRD(2022)·2 citations
04
[Submitted on 18 Jun 2021]
Shell model analysis of the $B (E 2, 2^{+} \to 0^{+})$ 's in the A=70 T=1 triplet
S. M. Lenzi · A. Poves · A. O. Macchiavelli
he $B (E 2, 2^{+} \to 0^{+})$ transition strengths of the T=1 isobaric triplet $^{70}$ Kr, $^{70}$ Br, $^{70}$ Se, recently measured at RIKEN/RIBF, are discussed in terms of state of the art large scale shell model calculations using the JUN45 and JUN45+LNPS plus Coulomb interactions. In this letter we argue that, depending on the effective charges used, the calculations are either in line with the experimental data within statistical uncertainties, or the anomaly happens in $^{70}$ Br, rather than $^{70}$ Kr. In the latter case, we suggest that it can be due to the presence of a hitherto undetected 1 $^{+}$ T=0 state below the yrast 2 $^{+}$ T=1 state. Our results do not support a shape change of $^{70}$ Kr with respect to the other members of the isobaric multiplet.
Comments:
4 pages, 3 figures. To be submitted to Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2106.10269 [pdf]
PRC(2021)·13 citations

Affiliations

first authorsco-authorsvia INSPIRE

Statistical Multifragmentation Model Within the Extended Morphological Thermodynamics Approach

Decoding the Density Dependence of the Nuclear Symmetry Energy

Study of neutrino-nucleus reactions with CRISP Program (0 < Eν​ < 3 GeV)

Shell model analysis of the B(E2,2+→0+)'s in the A=70 T=1 triplet

Affiliations

Study of neutrino-nucleus reactions with CRISP Program (0 < $E_{ν}$ < 3 GeV)

Shell model analysis of the $B (E 2, 2^{+} \to 0^{+})$ 's in the A=70 T=1 triplet