Nuclear Theory·nucl-th

Tuesday·June 2, 2020

18 papers—12 primary·6 cross-listed

01
[Submitted on 29 May 2020]
Systematic Matter and Binding-Energy Distributions from a Dispersive Optical Model Analysis
C. D. Pruitt · R. J. Charity · L. G. Sobotka · M. C. Atkinson · W. H. Dickhoff
We present the first systematic nonlocal dispersive optical model analysis using both bound-state and scattering data of $^{16, 18}$ O, $^{40, 48}$ Ca, $^{58, 64}$ Ni, $^{112, 124}$ Sn, and $^{208}$ Pb. In all systems, roughly half the total nuclear binding energy is associated with the most-bound 10% of the total nucleon density. The extracted neutron skins reveal the interplay of asymmetry, Coulomb, and shell effects on the skin thickness. Our results indicate that simultaneous optical model fits of inelastic scattering and structural data on isotopic pairs are effective for constraining asymmetry-dependent nuclear structural quantities otherwise difficult to observe experimentally.
Comments:
6 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2006.00021 [pdf]
PRL(2020)·31 citations
02
[Submitted on 30 May 2020]
$g$ -factor and static quadrupole moment for the wobbling mode in $^{133}$ La
Q. B. Chen🇩🇪 · S. Frauendorf🇺🇸 · N. Kaiser🇩🇪 · Ulf-G. Meißner🇩🇪 · J. Meng🇨🇳
The $g$ -factor and static quadrupole moment for the wobbling mode in the nuclide $^{133}$ La are investigated as functions of the spin $I$ by employing the particle rotor model. The model can reproduce the available experimental data of $g$ -factor and static quadrupole moment. The properties of the $g$ -factor and static quadrupole moment as functions of $I$ are interpreted by analyzing the angular momentum geometry of the collective rotor, proton-particle, and total nuclear system. It is demonstrated that the experimental value of the $g$ -factor at the bandhead of the yrast band leads to the conclusion that the rotor angular momentum is $R ≃ 2$ . Furthermore, the variation of the $g$ -factor with the spin $I$ yields the information that the angular momenta of the proton-particle and total nuclear system are oriented parallel to each other. The negative values of the static quadrupole moment over the entire spin region are caused by an alignment of the total angular momentum mainly along the short axis. Static quadrupole moment differences between the wobbling and yrast band originate from a wobbling excitation with respect to the short axis.
Comments:
6 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2006.00259 [pdf]
PLB(2020)·26 citations
03
[Submitted on 30 May 2020]
Revisiting an extended-mean-field approach in heavy-ion collisions around the Fermi energy
G. Besse🇫🇷 · V. de la Mota🇫🇷 · E. Bonnet🇫🇷 · P. Eudes🇫🇷 · P. Napolitani🇫🇷 · Z. Basrak🇭🇷
Static and dynamical aspects of nuclear systems are described through an extended time-dependent mean-field approach. The foundations of the formalism are presented, with highlights on the estimation of average values and their corresponding dispersions. In contrast to semiclassical transport models, the particular interest of this description lies on its intrinsic quantal character. The reliability of this approach is discussed by means of stopping-sensitive observables analysis in heavy-ion collisions in the range of 20 to 120 MeV per nucleon.
Comments:
11 pages, 11 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2006.00338 [pdf]
PRC(2020)·4 citations
04
[Submitted on 31 May 2020]
Correspondence between Israel-Stewart and first-order casual and stable hydrodynamics for the boost-invariant massive case with zero baryon density
Arpan Das🇵🇱 · Wojciech Florkowski🇵🇱 · Radoslaw Ryblewski🇵🇱
Exact correspondence between Israel-Stewart theory and first-order causal and stable hydrodynamics is established for the boost-invariant massive case with zero baryon density and the same constant relaxation times used in the shear and bulk sectors. Explicit expressions for the temperature dependent regulators are given for the case of a relativistic massive gas. The stability and causality conditions known in the first-order approach are applied and one finds that one of them is violated in this case.
Comments:
7 pages, 1 figure
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2006.00536 [pdf]
PRD(2020)·19 citations
05
[Submitted on 31 May 2020]
The isoscalar features of Pygmy Dipole Resonance: a subtle game of symmetry energy
V. Baran · T. Isdraila · M. Colonna · D. I. Palade · A. I. Nicolin
The vibrational structure of the Pygmy Dipole Resonance (PDR) is investigated within a quantum many-body treatment with extended separable interactions able to encode the dependence of nuclear symmetry energy on density. A new picture of PDR is unveiled in terms of a combined dynamics of the neutron skin and of the core isovector polarization, which determines the isoscalar features of PDR while reproducing the isovector properties of Giant Dipole Resonance. The key role played by the variation with density of the symmetry energy on shaping the low-lying dipole response and its isoscalar-isovector structure is underlined. Our results provide insights for the challenge of clarifying the transition from skin oscillation to a highly bulk collective dynamics.
Comments:
6 pages, 4 figures; corrected misprints, added new references
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2006.00638 [pdf]
0 citations
06
[Submitted on 1 Jun 2020]
Muon capture rates: Evaluation within the Quasiparticle Random Phase Approximation
Fedor Simkovic🇸🇰 · Rastislav Dvornicky🇸🇰 · Petr Vogel🇺🇸
The Quasiparticle Random Phase Approximation (QRPA) is used in evaluation of the total muon capture ratesfor the final nuclei participating in double-beta decay. Several variants of the method are used, depending on the size of the single particle model space used, or treatment of the initial bound muon wave function. The resulting capture rates are all reasonably close to each other. In particular, the variant that appears to be most realistic, results in rates in good agreement with the experimental values. There is no necessity for an empirical quenching of the axial current coupling constant $g_{A}$ . Its standard value $g_{A}$ = 1.27 seems to be adequate.
Comments:
13 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2006.00689 [pdf]
PRC(2020)·20 citations
07
[Submitted on 1 Jun 2020]
Network structure of thermonuclear reactions in nuclear landscape
H. L. Liu · D. D. Han · Y. G. Ma · L. Zhu
Nucleosynthesis is a complex process in astro-nuclear evolution. In this work, we construct a directed multi-layer nuclear reaction network using the substrate-product method from a thermonuclear reaction database, JINA REACLIB. The network contains four layers, namely $n$ -, $p$ -, $h$ - and $r$ , corresponding to the reaction types involved in neutrons, protons, $^{4}$ He and the remainder, respectively. The degree values (i.e. numbers of reactions) for three layers of n-, p- and h- have a significant correlation with one another, and their topological structures exhibit a similar regularity. However, the $r$ -layer has a more complex topological structure than others and has less correlation with the other three layers. A software package named `mfinder' is employed to analyze the motif structure of the nuclear reaction network. We thus identify the most frequent reaction patterns of interconnections occurring among different nuclides. This work provides a novel approach to study the nuclear reaction network prevailing in the astrophysical context.
Comments:
7 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2006.00713 [pdf]
SCPMA(2020)·9 citations
08
[Submitted on 1 Jun 2020]
Magnetic field effects in peripheral heavy-ion collisions around 1 GeV/nucleon
X. G. Deng🇨🇳 · Y. G. Ma🇨🇳
Magnetic field effects on free nucleons are studied in peripheral collisions of $^{197}$ Au + $^{197}$ Au at energies ranging from 600 to 1500 MeV/nucleon by utilizing an isospin-dependent quantum molecular dynamics (IQMD) model. With the help of angular distributions and two-particle angular correlators, the magnetic field effect at an impact parameter of 11 fm is found to be more obvious than at an impact parameter of 8 fm. Moreover, the results suggest that with an increase in the number of peripheral collisions, protons are more easily condensed with the magnetic field. Magnetic field effects are further investigated by the ratio of free neutrons to free protons as functions of a two-particle correlator $C_{2}$ , four-particle correlator $C_{4}$ and six-particle correlator $C_{6}$ of angle $ϕ$ , rapidity $Y$ and transverse momentum $p_{T}$ . The results show that weak magnetic field effects could be revealed more clearly by these multiple-particle correlators, with the larger number of particle correlators demonstrating a clear signal. The results highlight a new method to search for weak signals using multi-particle correlators.
Comments:
7 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2006.00718 [pdf]
PRC(2020)·7 citations
09
[Submitted on 1 Jun 2020]
Two-proton momentum correlation from photondisintegration of $α$ -clustering light nuclei in the quasi-deuteron region
B. S. Huang · Y. G. Ma
The proton-proton momentum correlation function is constructed in three-body photo-disintegration channels from $^{12}$ C and $^{16}$ O targets in the quasi-deuteron regime within the framework of an extended quantum molecular dynamics model. Using the formula of Lednicky and Lyuboshitz (LL) for the momentum correlation function, we obtain a proton-proton momentum correlation function for the specific three-body photon-disintegration channels of $^{12}$ C and $^{16}$ O targets, which are assumed to have different initial geometric structures, and extract their respective emission source sizes for the proton-proton pair. The results demonstrate that constructing a proton-proton momentum correlation is feasible in photo-nuclear reactions, and it is sensitive to the initial nuclear structure. For future experimental studies investigating the $α$ -clustering structures of light nuclei, the present work can be used to shed light on the performance and correlation function analysis of ( $γ$ ,pp) or (e, $e^{'}$ pp) reactions.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2006.00722 [pdf]
PRC(2020)·23 citations
10
[Submitted on 1 Jun 2020]
Strength of pairing interaction for hyperons in multistrangeness hypernuclei
Yu-Ting Rong🇨🇳 · Pengwei Zhao🇨🇳 · Shan-Gui Zhou🇨🇳
Pairing correlations play a very important role in atomic nuclei. Although several effective pairing interactions have been used in mean field calculations for nucleons, little is known about effective pairing interactions for hyperons. Based on the quark model, we propose a relationship between effective pairing interactions for hyperons and for nucleons; e.g., for $Λ$ s, the strength of the pairing interaction is 4/9 of that for nucleons. A separable pairing force of finite range which has been widely applied to describing pairing correlations in normal nuclei is used to investigate pairing effects in multi- $Λ$ Ca, Sn and Pb hypernuclei.
Comments:
17 pages, 3 figures; Phys. Lett. B, in press
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2006.00797 [pdf]
PLB(2020)·32 citations
11
[Submitted on 1 Jun 2020]
Constraining hadron-quark phase transition parameters within the quark-mean-field model using multimessenger observations of neutron stars
Zhiqiang Miao🇨🇳 · Ang Li🇨🇳 · Zhenyu Zhu🇨🇳 · Sophia Han🇺🇸
We extend the quark mean-field (QMF) model for nuclear matter and study the possible presence of quark matter inside the cores of neutron stars. A sharp first-order hadron-quark phase transition is implemented combining the QMF for the hadronic phase with "constant-speed-of-sound" parametrization for the high-density quark phase. The interplay of the nuclear symmetry energy slope parameter, $L$ , and the dimensionless phase transition parameters (the transition density $n_{trans} / n_{0}$ , the transition strength $Δ ε / ε_{trans}$ , and the sound speed squared in quark matter $c_{QM}^{2}$ ) are then systematically explored for the hybrid star proprieties, especially the maximum mass $M_{max}$ and the radius and the tidal deformability of a typical $1.4 M_{⊙}$ star. We show the strong correlation between the symmetry energy slope $L$ and the typical stellar radius $R_{1.4}$ , similar to that previously found for neutron stars without a phase transition. With the inclusion of phase transition, we obtain robust limits on the maximum mass ( $M_{max} < 3.6 M_{⊙}$ ) and the radius of $1.4 M_{⊙}$ stars ( $R_{1.4} ≳ 9.6 km$ ), and we find that a too-weak ( $Δ ε / ε_{trans} ≲ 0.2$ ) phase transition taking place at low densities $≲ 1.3 - 1.5 n_{0}$ is strongly disfavored. We also demonstrate that future measurements of the radius and tidal deformability of $\sim 1.4 M_{⊙}$ stars, as well as the mass measurement of very massive pulsars, can help reveal the presence and amount of quark matter in compact objects.
Comments:
15 pages, 12 figures, 1 table, version accepted for publication in ApJ
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
2006.00839 [pdf]
ApJ(2020)·56 citations
12
[Submitted on 1 Jun 2020]
Modification of tensor force in \textit{p}-shell effective interaction
Kanhaiya Jha · Pawan Kumar · Shahariar Sarkar · P. K. Raina
In many shell model interactions, the tensor force monopole matrix elements often retain systematic trends originating in the bare tensor force. However, in the present work, we find that Isospin T = 0 tensor force monopole matrix elements of \textit{p}-shell effective interaction CK(8-16) do not share these systematic. We correct these discrepancies by modifying T = 0 tensor force two-body matrix elements (TBMEs) of CK(8-16) by the analytically calculated tensor force TBMEs. With some additional modification of single-particle energies and TBMEs, the revised effective interaction is named as CKN. The effective interaction CKN has been tested for the calculations of \textit{p}-shell nuclei of normal parity states from various physics viewpoints such as excitation spectra, electromagnetic moments, and electromagnetic and \textit{G}amow-\textit{T}eller (\textit{GT}) transitions. The obtained results are found to be satisfactory.
Comments:
21 pages, 10 figures, 6 tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2006.00889 [pdf]
IJMPE(2020)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE