Nuclear Theory·nucl-th

Tuesday·April 25, 2023

13 papers—8 primary·5 cross-listed

01
[Submitted on 22 Apr 2023]
Initial Vorticities of Quark-Gluon Matter in Heavy-ion Collisions
An-Ke Lei🇨🇳 · Du-Juan Wang🇨🇳 · Dai-Mei Zhou🇨🇳 · Ben-Hao Sa🇨🇳 · Laszlo Pal Csernai🇳🇴 · Larissa V. Bravina🇳🇴
We calculate four types of initial vorticities in Au+Au collisions at energies $S_{N N}$ = 5--200 GeV using a microscopic transport model PACIAE. Our simulation shows the non-monotonic dependence of the initial vorticities on the collision energies. The energy turning point is around 10-15 GeV for different vorticities but not sensitive to impact parameter.
Comments:
6 pages, 2 figures, 10th International Conference on New Frontiers in Physics (ICNFP 2021)
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
arXiv:
2304.11343 [pdf]
IJMPE(2023)·0 citations
02
[Submitted on 22 Apr 2023]
Neutrino-induced neutral- and charged-current reactions on $^{40}$ Ar
Toshio Suzuki🇯🇵 · Noritaka Shimizu🇯🇵
Neutrino-induced reactions on $^{40}$ Ar are investigated by shell model for Gamow-Teller transitions and random-phase-approximation (RPA) for forbidden transitions. For the 1 $^{+}$ multipole, an effective interaction in $s d$ - $p f$ shell obtained by the extended Kuo-Krenciglowa (EKK) method from chiral interactions is used to study $B (GT)$ , charged-current reaction $^{40}$ Ar ( $ν_{e}$ , $e^{-}$ ) $^{40}$ K, $B (M 1)$ in $^{40}$ Ar and neutral-current reaction $^{40}$ Ar ( $ν$ , $ν$ ') $^{40}$ Ar. A considerable quenching for spin modes is found in the analysis of $B (M 1)$ , and this quenching is taken into account for the evaluation of the cross sections of the neutral-current reaction. The sensitive dependence of the reaction cross sections on the quenching of the axial-vector coupling constant, $g_{A}$ , is pointed out.
Comments:
8 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2304.11358 [pdf]
PRC(2023)·1 citation
03
[Submitted on 23 Apr 2023]
Relativistic effects in Green's function Monte Carlo calculations of neutrino-nucleus scattering
Alexis Nikolakopoulos🇺🇸 · Alessandro Lovato🇺🇸 · Noemi Rocco🇺🇸
Microscopic calculations of neutrino-nucleus scattering cross sections are critical for the success of the neutrino-oscillation program. In addition to retaining nuclear correlations in the initial and final state of the reaction, they are based on consistent nuclear interactions and transition current operators, thereby enabling robust uncertainty quantification. In this work, we address a significant limitation of these microscopic methods, which arises from their nonrelativistic nature. By performing the calculations in a reference frame that minimizes nucleon momenta and utilizing the so-called ``two-fragment'' model, we extend the applicability of Green's function Monte Carlo calculations of neutrino-nucleus scattering to higher momenta than currently possible. To validate this approach, we compare our theoretical predictions against inclusive data measured by the MiniBooNE, T2K, and MINER $ν$ A experiments.
Comments:
12 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Theory (hep-th)
arXiv:
2304.11772 [pdf]
PRC(2024)·14 citations
04
[Submitted on 24 Apr 2023]
Shape transition of Nd and Sm isotopes and neutrinoless double-beta decay nuclear matrix element of $^{150}$ Nd
Yusuke Tsunoda🇯🇵 · Noritaka Shimizu🇯🇵 · Takaharu Otsuka🇯🇵
Neutron-rich Nd and Sm isotopes are known to exhibit shape phase transition as a function of neutron number. Among them, $^{150}$ Nd and $^{150}$ Sm are important not only because they are transitional nuclei, but also the parent and daughter nuclei of double-beta decay. We performed large-scale shell-model calculations of even-even Nd and Sm isotopes including the spherical-deformed shape transition. The quasi-particle vacua shell model enables us to perform shell-model calculations with sufficiently large model space with the $^{110}$ Zr inert core. The shell-model result well reproduces the experimental excitation energies and quadrupole properties of the yrast and non-yrast states. The nuclear matrix element of neutrinoless double-beta decay of $^{150}$ Nd is evaluated showing its modest enhancement by shape mixing.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2304.11780 [pdf]
PRC(2023)·18 citations
05
[Submitted on 24 Apr 2023]
Triaxial-shape dynamics in the low-lying excited $0^{+}$ state: Role of the collective mass
Kouhei Washiyama · Kenichi Yoshida
Background: Non-yrast states in neutron-rich nuclei are being investigated experimentally. These states reveal various aspects and details of the nuclear structure, such as the fluctuation around the axially symmetric shape. Purpose: The beyond-mean-field effects in neutron-rich nuclei with $N ≃ 28$ are investigated. We focus on the role of collective mass in triaxial-shape dynamics. Method: We employ the five-dimensional quadrupole collective Hamiltonian method with the potential obtained in a constrained Hartree--Fock--Bogoliubov approach with a Skyrme energy-density functional and the collective-mass functions obtained by the cranking approximation. The method includes triaxial deformations. Results: We find that $^{42}$ Mg, $^{40}$ Si, $^{44}$ S, and $^{46}$ S show $γ$ -soft: A flat behavior in the potential energy surface along the triaxial deformation. Their low-lying spectra show a strong nucleus dependence, while those obtained with a collective mass assumed as constant are similar to each other. The energy ratio $E (0_{2}^{+}) / E (2_{1}^{+})$ and the $B (E 2)$ ratio $B (E 2; 0_{2}^{+} \to 2_{1}^{+}) / B (E 2; 2_{1}^{+} \to 0_{1}^{+})$ show a unique property of the $0_{2}^{+}$ state, while the energy and $B (E 2)$ ratios in neutron-deficient $γ$ -soft nuclei with $N = 78$ do not depend on nucleus so much. Conclusions: Low-lying spectra are determined by not only the potential energy but also the collective mass. We clarify the important role of the collective mass in low-energy dynamics in the neutron-rich $N \sim 28$ nuclei.
Comments:
8 pages, 9 figures, accepted for publication in Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2304.11918 [pdf]
PRC(2023)·5 citations
06
[Submitted on 24 Apr 2023]
Relativistic configuration-interaction density functional theory: Nonaxial effects on nuclear $β β$ decay
Y. K. Wang🇨🇳 · P. W. Zhao🇨🇳 · J. Meng🇨🇳
The relativistic configuration-interaction density functional theory is developed for even-even and odd-odd nuclei and is used to predict the nuclear matrix element of the neutrinoless $β β$ ( $0 ν β β$ ) decay in nucleus $^{76}$ Ge, amongst the most promising $β β$ -decay candidates. The nonaxial deformation, i.e., triaxiality, which poses severe challenges in evaluating the nuclear matrix element of $^{76}$ Ge, is incorporated within a full model space for the first time. The spectroscopic properties of the $β β$ -decay partners $^{76}$ Ge and $^{76}$ Se, and the nuclear matrix element governing the two-neutrino $β β$ ( $2 ν β β$ ) decay in $^{76}$ Ge are well reproduced, providing solid examinations for the validity of theoretical calculations. The inclusion of the triaxial degree of freedom enhances the nuclear matrix element of the $0 ν β β$ decay significantly by a factor around two. The present results indicate that the goals of next-generation experiments searching for the $0 ν β β$ decay in $^{76}$ Ge can be achieved using only a quarter amount of the experimental materials.
Comments:
10 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2304.12009 [pdf]
Sci.Bull.(2024)·26 citations
07
[Submitted on 24 Apr 2023]
Cluster formation near midrapidity -- can the mechanism be identified experimentally?
V. Kireyeu🇩🇪 · G. Coci🇩🇪 · S. Glaessel🇩🇪 · J. Aichelin🇫🇷 · C. Blume🇩🇪 · E. Bratkovskaya🇩🇪
The formation of weakly bound clusters in the hot and dense environment at midrapidity is one of the surprising phenomena observed experimentally in heavy-ion collisions from a low center of mass energy of a few GeV up to a ultra-relativistic energy of several TeV. Three approaches have been advanced to describe the cluster formation: coalescence at kinetic freeze-out, cluster formation during the entire heavy-ion collision by potential interaction between nucleons and deuteron production by hadronic reactions. We identify experimental observables, which can discriminate these production mechanisms for deuterons.
Comments:
typos corrected, updated plots
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2304.12019 [pdf]
PRC(2024)·19 citations
08
[Submitted on 24 Apr 2023]
Probing the neutron-skin of unstable nuclei with heavy ion collisions
Junping Yang · Xiang Chen · Ying Cui · Zhuxia Li · Yingxun Zhang
To improve the constraints of symmetry energy at subsaturation density, measuring and accumulating more neutron skin data for neutron rich unstable nuclei is naturally required. Aiming to probe the neutron skin of unstable nuclei by using low-intermediate energy heavy ion collisions, we develop a new version of improved quantum molecular dynamics model, in which the neutron skin of the initial nucleus and the mean field potential in nucleon propagation are consistently treated. Our calculations show that the three observables, such as the cross sections of the primary projectile-like residues with $A > 100$ ( $σ_{A > 100}$ ), the difference of $σ_{A > 100}$ between $^{132}$ Sn+ $^{124}$ Sn and $^{124}$ Sn+ $^{124}$ Sn systems ( $δ σ_{A > 100}$ ), and the neutron to proton yield ratio ( $R (n / p)$ ) in the transverse direction, could be used to measure the neutron skin of the unstable nuclei and to constrain the slope of the symmetry energy in the future.
Comments:
9 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2304.12059 [pdf]
Universe(2023)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE