Nuclear Theory·nucl-th

Tuesday·June 1, 2021

14 papers—8 primary·6 cross-listed

01
[Submitted on 28 May 2021]
Hyperonization in compact stars
Armen Sedrakian🇩🇪 · Jia-Jie Li🇨🇳 · Fridolin Weber🇺🇸
We review the covariant density functional approach to the equation of state of the dense nuclear matter in compact stars. The main emphasis is on the hyperonization of the dense matter, and the role played by the $Δ$ -resonances. The implications of hyperonization for the astrophysics of compact stars, including the equation of state, composition, and stellar parameters are examined. The mass-radius relation and tidal deformabilities of static and rapidly rotating (Keplerian) configurations are discussed in some detail. We briefly touch upon some other recent developments involving hyperonization in hot hypernuclear matter at high- and low-densities.
Comments:
v3: matches final version, references updated; v2: 47 pages, 11 figures, minor corrections; v1: 45 pages, 11 figures, chapter to appear in "Astrophysics in the XXI century with compact stars", World Scientific, eds. Cesar Zen Vasconcellos and Fridolin Weber
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
2105.14050 [pdf]
12 citations
02
[Submitted on 29 May 2021]
The isoscalar monopole strength of 13C
S. Shin · B. Zhou · M. Kimura
To identify the 3alpha BEC state with the excess neutron, we have investigated the monopole strength of the excited states of 13C by using the theoretical framework of the real-time evolution method. The calculations have revealed several candidates of the Hoyle-analog states in a highly excited region.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2105.14178 [pdf]
Few Body Syst.(2021)·2 citations
03
[Submitted on 29 May 2021]
Multiplicity Scaling of Light Nuclei Production in Relativistic Heavy-Ion Collisions
Wenbin Zhao🇨🇳 · Kai-jia Sun🇺🇸 · Che Ming Ko🇺🇸 · Xiaofeng Luo🇨🇳
Using the nucleon coalescence model based on kinetic freeze-out nucleons from the 3D MUSIC+UrQMD and the 2D VISHNU hybrid model with a crossover equation of state, we study the multiplicity dependence of deuteron ( $d$ ) and triton ( $t$ ) production from central to peripheral Au+Au collisions at $s_{NN} =$ 7.7, 14.5, 19.6, 27, 39, 62.4 and 200 GeV and Pb+Pb at $s_{NN} = 2.76$ TeV, respectively. It is found that the ratio $N_{t} N_{p} / N_{d}^{2}$ of the proton yield $N_{p}$ , deuteron yield $N_{d}$ and triton yield $N_{t}$ exhibits a scaling behavior in its multiplicity dependence, i.e., decreasing monotonically with increasing charged-particle multiplicity. A similar multiplicity scaling of this ratio is also found in the nucleon coalescence calculation based on kinetic freeze-out nucleons from a multiphase transport (AMPT) model. The scaling behavior of $N_{t} N_{p} / N_{d}^{2}$ can be naturally explained by the interplay between the sizes of light nuclei and the nucleon emission source. We further argue that the multiplicity scaling of $N_{t} N_{p} / N_{d}^{2}$ can be used to validate the production mechanism of light nuclei, and the collision energy dependence of this yield ratio can further serve as a baseline in the search for the QCD critical point in relativistic heavy-ion collisions.
Comments:
9 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2105.14204 [pdf]
PLB(2021)·47 citations
04
[Submitted on 30 May 2021]
Neutron drop trapped in axially deformed external fields
Xiaohan Ding · Jinniu Hu · Ying Zhang · Hong Shen
The neutron drop is firstly investigated in an axially symmetric harmonic oscillator (ASHO) field, whose potential strengths of different directions can be controlled artificially. The shape of the neutron drop will change from spherical to oblate or prolate according to the anisotropy of the external field. With the potential strength increasing in the axial direction, the neutron prefers to occupy the orbital perpendicular to the symmetry axis. On the contrary, the neutron likes to stay in the orbital parallel to the symmetry axis when the potential strength increases in the radial direction. Meanwhile, when the potential strength of one direction disappears, the neutron drop cannot bind together. These investigations are not only helpful to simulate the properties of neutrons in finite nuclei but also provide the theoretical predictions to the future artificial operations on the nuclei like the ultracold atom system, for a deeper realization of quantum many-body systems.
Comments:
14 pages, 4 figures, 1 table, accepted by Nucl. Phys. A
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2105.14407 [pdf]
NPA(2021)·0 citations
05
[Submitted on 30 May 2021]
Constraining the relativistic mean-field models from PREX-2 data: Effective forces revisited
Jeet Amrit Pattnaik · R. N. Panda · M. Bhuyan · S. K. Patra
Based on the current measurement of the neutron distribution radius ( $R_{n}$ ) of $^{208}$ Pb through the PREX-2 data, we re-visited the recently developed G3 and IOPB-I force parameter by fine-tuning some of the specific couplings within the relativistic mean-field model. The $ω - ρ -$ mesons coupling $Λ_{ω}$ and the $ρ -$ meson coupling $g_{ρ}$ are refitted to reproduce the experimental neutron radius of $^{208}$ Pb without compromising the bulk properties of finite nuclei and infinite nuclear matter observables. The modified parameter sets are applied to calculate the gross properties of finite nuclei for a few double closed-shell nuclei and further used to obtain the various infinite nuclear matter observables at saturation. In addition to these, the force parameters are adopted to calculate the properties of high isospin asymmetry dense system such as neutron star matter and tested for the validation for the constraint from GW170817 binary neutron star merger events. The tuned forces are predicting relatively good results for finite and infinite nuclear matter systems and the current limitation on neutron radius from PREX-2. A systematic analysis using these two refitted parameter sets over the nuclear chat will be communicated shortly.
Comments:
6 pages,2 figures, and 3 tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2105.14479 [pdf]
CPC(2022)·17 citations
06
[Submitted on 30 May 2021]
Cross section of the Coulomb excitation of $^{229 m}$ Th by low energy muons
E. V. Tkalya
The inelastic scattering cross section for muons, $μ^{-}$ , with energies $E$ =9--100~eV from the $^{229}$ Th nuclei is calculated in the framework of the second order of the perturbation theory for the quantum electrodynamics. The dominant contribution to the excitation of the low energy isomer $^{229 m}$ Th $(3/ 2^{+}, 8.19 \pm 0.12$ ~eV) comes from the $E 2$ multipole. The excitation cross section reaches the value of $1 0^{- 21}$ cm $^{2}$ in the range $E \approx$ 10~eV. This is four to five orders of magnitude larger than the electron excitation cross section and enough for efficient excitation of $^{229 m}$ Th on the muon beam at the next generation of muon colliders.
Comments:
9 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2105.14597 [pdf]
CPC(2021)·5 citations
07
[Submitted on 31 May 2021]
The N=50 and Z=28 shell closure revisited
T.R. Routray · P. Bano · M. Anguiano · M. Centelles · X. Viñas · L.M. Robledo
Recent experiments performed in neutron-rich copper isotopes have revealed a crossing in the nucleus $^{75}$ Cu between the $3/ 2^{-}$ and $5/ 2^{-}$ levels, which correspond to the ground-state and the first excited state in isotopes with mass number below $A = 75$ . Due to the strong single-particle character of these states, this scenario can be investigated through the analysis of the proton spectrum provided by mean-field models in nickel isotopes with neutron numbers between $N$ =40 and $N$ =50. In this work we show that the aforementioned crossing is mainly driven by the mean-field provided by the effective nucleon-nucleon and spin-orbit interactions. We also analyze the impact of the tensor interaction, and find that in some mean-field models it is essential to reproduce the crossing of the 2 $p_{3/2}$ and 1 $f_{5/2}$ proton single-particle levels, as in the case of the SAMi-T Skyrme force and the D1M Gogny interaction, whereas in other cases, as for example the SLy5 Skyrme force, a reasonable tensor force appears to be unable to modify the mean-field enough to reproduce this level crossing. Finally, in the calculations performed with the so-called simple effective interaction (SEI), it is shown that the experimental data in nickel and copper isotopes considered in this work can be explained satisfactorily without any explicit consideration of the tensor interaction.
Comments:
7 pages, 3 figures, 1 table
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2105.15006 [pdf]
PRC(2021)·9 citations
08
[Submitted on 31 May 2021]
Information content of the parity-violating asymmetry in $^{208}$ Pb
Paul-Gerhard Reinhard🇩🇪 · Xavier Roca-Maza🇮🇹 · Witold Nazarewicz🇺🇸
The parity violating asymmetry $A_{P V}$ in $^{208}$ Pb, recently measured by the PREX-2 collaboration, is studied using modern relativistic (covariant) and non-relativistic energy density functionals. We first assess the theoretical uncertainty on $A_{P V}$ which is intrinsic to the adopted approach. To this end, we use quantified functionals that are able to accommodate our previous knowledge on nuclear observables such as binding energies, charge radii, and the dipole polarizability $α_{D}$ of $^{208}$ Pb. We then add the quantified value of $A_{P V}$ together with $α_{D}$ to our calibration dataset to optimize new functionals. Based on these results, we predict a neutron skin thickness in $^{208}$ Pb $r_{skin} = 0.19 \pm 0.02$ \,fm and the symmetry-energy slope $L = 54 \pm 8$ \,MeV. These values are consistent with other estimates based on astrophysical data and are significantly lower than those recently reported using a particular set of relativistic energy density functionals. We also make a prediction for the $A_{P V}$ value in $^{48}$ Ca that will be soon available from the CREX measurement.
Comments:
11 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2105.15050 [pdf]
PRL(2021)·150 citations

Affiliations

first authorsco-authorsvia INSPIRE