Nuclear Theory·nucl-th

Tuesday·October 29, 2024

14 papers—7 primary·7 cross-listed

01
[Submitted on 26 Oct 2024]
Influences of $Z = 100$ and $N = 152$ deformed shells on $K^{π} = 8^{-}$ isomers and rotational bands in $N = 150$ isotones
Jun Zhang · Hai-Qian Zhang · T. M. Shneidman · R. V. Jolos · Xiao-Tao He
The $K^{π} = 8^{-}$ isomeric states and rotational bands in the even-even $N = 150$ isotones with $94 ⩽ Z ⩽ 104$ are investigated by the cranked shell model (CSM) with pairing correlations treated by the particle-number-conserving (PNC) method. The experimental bandhead energies and kinematic moments of inertia (MOIs) are reproduced quite well by the PNC-CSM calculation. The two-neutron state with configuration $ν 9/ 2^{-} [734] \otimes ν 7/ 2^{+} [624]$ is the lowest $8^{-}$ state for these isomers. This is a demonstration of the deformed neutron shell at $N = 152$ . Low-lying two proton $π^{2} 8^{-}$ ( $π 9/ 2^{+} [624] \otimes π 7/ 2^{-} [514]$ ) configuration state is predicted only for $^{252}$ No and $^{254}$ Rf due to the deformed proton shell at $Z = 100$ . A distinct upbending is observed for the $ν^{2} 8^{-}$ bands in the lighter isotones while it is absent for bands in the heavier ones. The upbending of the $ν^{2} 8^{-}$ band at frequency $ℏ ω \approx 0.20$ MeV in $^{244}$ Pu attributes to the sudden proton alignment of the interference term $j_{x} (π 5/ 2^{+} [642] \otimes π 7/ 2^{+} [633])$ . The irregularity of MOI observed in the $K^{π} = 8^{-}$ band of $^{252}$ No can be explained by the mixing of the $ν^{2} 8^{-}$ ( $ν 9/ 2^{-} [734] \otimes ν 7/ 2^{+} [624]$ ) and $π^{2} 8^{-}$ ( $π 9/ 2^{+} [624] \otimes π 7/ 2^{-} [514]$ ) configurations. The $20% - 30%$ increase of the bandhead $J^{(1)}$ for the $8^{-}$ bands comparing to the ground-state band is attributed to the $\sim 5%$ pairing gap reduction of the two-neutron $ν 7/ 2^{+} [624] \otimes ν 9/ 2^{-} [734]$ configuration state comparing to the ground-state band.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2410.20111 [pdf]
PRC(2025)·2 citations
02
[Submitted on 27 Oct 2024]
Medium recoil mode of $Δ$ production in single isobaric charge-exchange reactions
Xin Lei🇨🇳 · Erxi Xiao🇨🇳 · Yingge Huang🇨🇳 · Yujie Feng🇨🇳 · Hui Wang🇨🇳 · Jiali Huang🇨🇳 · Fuchang Gu🇨🇳 · Long Zhu🇨🇳 · Jun Su🇨🇳
The dynamic mechanisms underlying single charge-exchange reactions have been investigated using a theoretical framework that combines the Isospin-dependent Quantum Molecular Dynamics (IQMD) model with the statistical decay model GEMINI++. Two distinct channels contribute to the single isobaric charge-exchange reaction: quasi-elastic channel, where neutron-proton scattering drives the charge-exchange, and inelastic channel, where the $Δ$ particle is produced during the process. In a referenced study [Phys.RevC 106.014618(2022)], experimental data have revealed that the inelastic channel accounts for approximately 50 percent of the single isobaric charge-exchange reaction. However, our current model fails in reproducing the significant contribution of inelastic channel unless the novel medium recoil mode associated with $Δ$ production is considered in the calculations. Notably, this in-medium effect arising from inelastic nucleon-nucleon collisions is not yet incorporated into mainstream microscopic transport models. The dynamical properties of protons and pions emitting in the single isobaric charge-exchange reactions are predicted. This exploration of in-medium effects adds a valuable dimension to our understanding of the intricate dynamics involved in single charge-exchange reactions.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2410.20376 [pdf]
0 citations
03
[Submitted on 27 Oct 2024]
An approximation of the $S$ matrix for solving the Marchenko equation
N. A. Khokhlov
I present a new approximation of the $S$ -matrix dependence on momentum $q$ , formulated as a sum of a rational function and a truncated Sinc series. This approach enables pointwise determination of the $S$ matrix with specified resolution, capturing essential features such as resonance behavior with high accuracy. The resulting approximation provides a separable kernel for the Marchenko equation (fixed- $l$ inversion), reducing it to a system of linear equations for the expansion coefficients of the output kernel. Numerical results demonstrate good convergence of this method, applicable to both unitary and non-unitary $S$ matrices. Convergence is further validated through comparisons with an exactly solvable square-well potential model. The method is applied to analyze $S_{31}$ $π N$ scattering data.
Comments:
11 pages, 15 figures
Subjects:
Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2410.20409 [pdf]
PRC(2025)·2 citations
04
[Submitted on 27 Oct 2024]
Exploring Intruder Levels of Nuclei (96Zr, 98Zr, 98MO) Within the Framework of IBM-2 Model
Zainab S. M. · Ali N. Sabbar · Ali Mahdi Abdul Hussein
Current work includes a study of the very rare case called intruder nuclear levels, where there are only seven nuclei in nature. Such cases occur when the first excited state is . The current study included only three nuclei: . The nuclear model used to explore and investigate nuclei in this work is the second interacting boson. The experimental data and theoretical values obtained were in good agreement, indicating this model's success in calculating such anomalies. The main reason for the presence of these levels in other than their natural locations expected according to the IBM model is that they have a double subshell closure. The values of the electric quadrupole transitions, magnetic dipole transitions and zero transitions estimated were in acceptable agreement with experimental data.
Comments:
The research was not published in any journal, and substantial revisions were required
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2410.20566 [pdf]
0 citations
05
[Submitted on 28 Oct 2024]
The elliptic flow difference between baryons and anti-baryons in heavy collision with SMASH Model
Shuai Zhou🇨🇳 · Shusu Shi🇨🇳
A significant difference in the elliptic flow $v_{2}$ for particles and their corresponding antiparticles, which is more pronounced for baryons and anti-baryons, was observed in the STAR experiment during the Beam Energy Scan I (BES-I) at RHIC. By employing the SMASH model, we study the $v_{2}$ difference between protons and anti-protons, as well as between $Λ$ and $Λ ˉ$ , in Au + Au collisions at $s_{N N} = 7.7$ GeV as a function of evolution time. It finds that as the evolution time increases, the $v_{2}$ difference between protons and anti-protons becomes more pronounced compared to that between $Λ$ and $Λ ˉ$ . This phenomenon can be explained by the different constituent quarks of protons and $Λ$ . Since some of the $u$ quarks and $d$ quarks come from the colliding nuclei and are transported to mid-rapidity, they undergo more interactions than produced quarks, resulting in the proton $Δ v_{2}$ being larger than the $Λ$ $Δ v_{2}$ . We compare the SMASH calculations with STAR BES-I data and argue that higher precision data from BES-II will provide constraints on theoretical frameworks to interpret the $v_{2}$ differences of particles and anti-particles.
Comments:
6 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2410.20765 [pdf]
Chin.Phys.Lett.(2025)·3 citations
06
[Submitted on 28 Oct 2024]
Collective excitations in the hot QCD medium and the propagation of Heavy Quarks
Mohammad Yousuf Jamal🇮🇳 · Bedangadas Mohanty🇮🇳
This review explores the current understanding of collective excitations and the dynamics of heavy quark propagation in the quark-gluon plasma (QGP) formed in relativistic heavy-ion collisions. We focus on three core aspects: the theoretical modelling of the QGP, including momentum anisotropy, medium-induced collisions, finite chemical potential, and non-ideal interactions; the collective behaviours within the plasma; and the interaction dynamics of heavy quarks as they traverse the medium. Along with the polarization energy loss mechanisms, we also review the possibility of energy gain due to thermal field fluctuations. Lastly, we discuss how these theoretical insights can be tested through experiments and outline possible directions for future research.
Comments:
58 pages, 21 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
arXiv:
2410.20770 [pdf]
EPJA(2025)·1 citation
07
[Submitted on 28 Oct 2024]
Angular momentum dependence of $α$ -decay spectroscopic factors
E. V. Mardyban · D. F. Bayramov · A. Rahmatinejad · A. K. Azhibekov · K. Mendibayev · T. M. Shneidman
The probabilities to form an $α$ -particle on the surface of heavy nuclei (spectroscopic factors) in the states of different angular momenta are calculated within the dinuclear system (DNS) approach. It is shown that this dependence is determined not only by the energies of the excited states of the daughter nucleus, as is suggested by the Boltzmann distribution, but also by its quadrupole and octupole deformation parameters. The calculations were performed for actinide nuclei $^{222 - 228}$ Ra, $^{222 - 232}$ Th, $^{226 - 236}$ U, and $^{234 - 242}$ Pu. The results obtained will be useful in the future studies on the fine structure of alpha-decay.
Comments:
14 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2410.21096 [pdf]
Commun.Theor.Phys.(2026)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE

Influences of Z=100 and N=152 deformed shells on Kπ=8− isomers and rotational bands in N=150 isotones

Medium recoil mode of Δ production in single isobaric charge-exchange reactions

An approximation of the S matrix for solving the Marchenko equation

Exploring Intruder Levels of Nuclei (96Zr, 98Zr, 98MO) Within the Framework of IBM-2 Model

The elliptic flow difference between baryons and anti-baryons in heavy collision with SMASH Model

Collective excitations in the hot QCD medium and the propagation of Heavy Quarks

Angular momentum dependence of α-decay spectroscopic factors

Affiliations

Influences of $Z = 100$ and $N = 152$ deformed shells on $K^{π} = 8^{-}$ isomers and rotational bands in $N = 150$ isotones

Medium recoil mode of $Δ$ production in single isobaric charge-exchange reactions

An approximation of the $S$ matrix for solving the Marchenko equation

Angular momentum dependence of $α$ -decay spectroscopic factors