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
08
[Submitted on 25 Oct 2024] (cross-list from hep-ph)
A Universal Bound on QCD Axions from Supernovae
Konstantin Springmann🇩🇪 · Michael Stadlbauer🇩🇪 · Stefan Stelzl🇨🇭 · Andreas Weiler🇩🇪
We identify a new production channel for QCD axions in supernova environments that contributes to axion emissivity for all models solving the strong CP problem. This channel arises at tree-level from a shift-symmetry-breaking operator constructed at next-to-leading order in Chiral Perturbation Theory. In scenarios where model-dependent derivative couplings to nucleons are absent, this sets the strongest model-independent constraint on the axion mass, improving on existing bounds by two orders of magnitude.
Comments:
7 pages, 9 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2410.19902 [pdf]
PRD(2025)·42 citations
09
[Submitted on 25 Oct 2024] (cross-list from astro-ph.HE)
Resonant shattering flares as asteroseismic tests of chiral effective field theory
Duncan Neill🇬🇧 · David Tsang🇬🇧 · Christian Drischler🇺🇸 · Jeremy W. Holt🇺🇸 · William G. Newton🇺🇸
Chiral effective field theory ( $χ$ EFT) has proved to be a powerful microscopic framework for predicting the properties of neutron-rich nuclear matter with quantified theoretical uncertainties up to about twice the nuclear saturation density. Tests of $χ$ EFT predictions are typically performed at low densities using nuclear experiments, with neutron star (NS) constraints only being considered at high densities. In this work, we discuss how asteroseismic quasi-normal modes within NSs could be used to constrain specific matter properties at particular densities, not just the integrated quantities to which bulk NS observables are sensitive. We focus on the crust-core interface mode, showing that measuring this mode's frequency would provide a meaningful test of $χ$ EFT at densities around half the saturation density. Conversely, we use nuclear matter properties predicted by $χ$ EFT to estimate that this mode's frequency is around 185 $\pm$ 50 Hz. Asteroseismic observables such as resonant phase shifts in gravitational-wave signals and multimessenger resonant shattering flare timings, therefore, have the potential to provide useful tests of $χ$ EFT.
Comments:
9 pages, 5 figures, submitted to Phys Rev C
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2410.19971 [pdf]
PRC(2025)·2 citations
10
[Submitted on 26 Oct 2024] (cross-list from astro-ph.SR)
Re analysis of Temperature Dependent Neutron Capture Rates and Stellar \b{eta} decay Rates of 95 98Mo
Abdul Kabir · Jameel-Un Nabi · Muhammad Tahir · Abdul Muneem · Zain Ul Abideen
The neutron capture rates and temperature dependent stellar beta decay rates of Mo isotopes are investigated within the framework of the statistical code (Talys v1.96) and proton neutron quasi particle random phase approximation (pnQRPA) models. The Maxwellian average cross section (MACS) and neutron capture rates for 95 98Mo(n,{\gamma}) 96 99Mo radiative capture processes are analyzed within the framework of statistical code Talys v1.96 based on the phenomenological nuclear level density (NLD) parameters and gamma strength functions (GSFs). The current model based computed data for MACS provide a good comparison with the existing measured data. The temperature dependent stellar \b{eta} decay rates of 95 98Mo are investigated at different densities within the framework of the pn-QRPA model. For the considered temperature range, the neutron capture rates were found to be higher, by orders of magnitude, than the stellar \b{eta} rates.
Comments:
10 pages, 7 figures
Subjects:
Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2410.20086 [pdf]
CPC(2024)·1 citation
11
[Submitted on 27 Oct 2024] (cross-list from hep-ph)
Revisiting $K N$ elastic and charge exchange reactions in search of the pentaquark $Θ^{+}$ baryon
Byung-Geel Yu🇰🇷 · Kook-Jin Kong🇰🇷 · Tae Keun Choi🇨🇦
In the search for the pentaquark $Θ^{+}$ baryon, the world data on $K^{+} n \to K^{+} n$ and $K^{+} n \to K^{0} p$ reactions on the deuteron target and $K^{0} p \to K^{+} n$ and $K_{L}^{0} p \to K_{S}^{0} p$ reactions on the hydrogen target are revisited to study the isoscalar component of the scattering amplitudes. The determination of the $s$ - and $p$ -wave phase shifts for the two former channels on the deuteron target is presented in the low momentum region with the uncertainty due to the deuteron form factors at forward angles discussed. For the reactions on hydrogen targets, a similarity expected from time reversal between the charge exchange processes $K^{+} n \to K^{0} p$ and $K^{0} p \to K^{+} n$ is exploited, while we present the analysis of the $K_{L}^{0} p \to K_{S}^{0} p$ scattering based on the $s$ -wave phase shift for low momenta combined with the $t$ -channel $ρ^{0} (775) + ω (782) + ϕ (1020)$ vector meson exchange at high momenta. With the mass 1535 MeV and decay width 5 MeV the possibility of the $Θ^{+}$ in the Breit-Wigner (BW) form is tested in the differential cross section measured by C. J. S. Damerell {\it et\ al.} at $P_{Lab} = 434$ MeV/ $c$ and polarization. Our analysis suggests measuring the polarization observable rather than the differential cross section, which has sufficient sensitivity to distinguish the $Θ^{+}$ baryon among all spin and parity states $J^{P} = 1/ 2^{\pm}$ and $3/ 2^{\pm}$ .
Comments:
20 pages, 14 figures, Acta Physica Polonica B memorial volume dedicated to Mitya Diakonov, Victor Petrov and Maxim Polyakov
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2410.20554 [pdf]
Acta Phys.Polon.B(2025)·0 citations
12
[Submitted on 28 Oct 2024] (cross-list from hep-ph)
Fluctuations and correlations of quark spin in hot and dense QCD matter
Hao-Lei Chen🇨🇳 · Wei-jie Fu🇨🇳 · Xu-Guang Huang🇨🇳 · Guo-Liang Ma🇨🇳
In this work, we examine the impact of QCD phase transitions on the quark spin fluctuations and correlations. We propose the quark-antiquark correlation, which relates to the vector meson spin alignment and the $Λ - Λ ˉ$ correlation, can be used as a novel probe of the critical end point (CEP) in the QCD phase diagram. Using the Nambu-Jona-Lanisio model, we qualitatively study the properties of quark-antiquark spin correlations. Our findings reveal a peak structure near the CEP of the chiral phase transition, which may serve as an experimental signature of the CEP and account for the non-monotonic behavior of $ϕ$ meson alignment at low collision energies observed recently in experiments.
Comments:
7+5 pages, 4+5 figures, accepted for publication in Phys. Rev. Lett
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2410.20704 [pdf]
PRL(2025)·22 citations
13
[Submitted on 28 Oct 2024] (cross-list from hep-ph)
Effects of dark boson mediated feeble interaction between dark matter (DM) and quark matter on $f$ -mode oscillation of DM admixed quark stars
O. P. Jyothilakshmi🇮🇳 · Lakshmi J. Naik🇮🇳 · Debashree Sen🇰🇷 · Atanu Guha🇰🇷 · V. Sreekanth🇮🇳
We investigate the behavior of the prominent non-radial fundamental $f$ -mode oscillations of dark matter (DM) admixed strange quark stars (DMSQSs), by adopting an equation of state (EoS) developed in Ref.~\cite{Sen:2022pfr}, which considers the possible presence of feebly interacting DM in strange quark stars (SQSs) for the first time. Within the model, feeble interaction between fermionic DM $χ$ and strange quark matter (SQM) is invoked via a vector new physics mediator $ξ$ with coupling strength $y_{ξ}$ . The pure SQM is described by the vector MIT Bag model. By varying different EoS parameters, the structural properties viz. the mass, radius and tidal deformability ( $Λ$ ) of the DMSQSs are studied with respect to various astrophysical constraints. We study in detail the $f$ -mode spectra within the Cowling approximation by obtaining the frequencies as a function of mass, compactness and $Λ$ of the star. To the best of our knowledge, this study represents the first analysis of non-radial $f$ -mode oscillations of DMSQSs. Our investigation indicates that the presence of DM and its interaction with SQM has great impact on the $f$ -modes. We show that the $f$ -mode frequencies are larger for DMSQSs, which are largely populated with massive DM fermions, compared to the SQSs. Further, we obtain a linear empirical relation between the $f$ -modes and the average density of the star. We also find that the mass-scaled angular frequency varies universally with compactness and $ln Λ$ for DMSQSs. Further, our studies indicate that the inclusion of DM in compact stars reduces the deviation of $f$ -mode frequency from general relativistic to Cowling approximation.
Comments:
Version to appear in Eur. Phys. J. C (16 pages, 11 figures)
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2410.20923 [pdf]
EPJC(2025)·11 citations
14
[Submitted on 28 Oct 2024] (cross-list from hep-ph)
Elastic Dijet Production in Electron Scattering on a Longitudinally Polarized Proton at Small $x$ : A Portal to Orbital Angular Momentum Distributions
Yuri V. Kovchegov🇺🇸 · Brandon Manley🇺🇸
We calculate the elastic production of dijets from electron collisions with a longitudinally polarized proton target at small values of the Bjorken $x$ variable. Building on the pioneering proposals of \cite{Hatta:2016aoc,Bhattacharya:2022vvo, Bhattacharya:2023hbq, Bhattacharya:2024sck} for measuring the quark and gluon orbital angular momentum (OAM) distributions, our focus is on both the longitudinal double spin asymmetry (DSA) and longitudinal single spin asymmetry (SSA). We compute the numerators of these asymmetries in the small- $x$ formalism of the light-cone operator treatment. Utilizing the small- $x$ expressions for the OAM distributions derived in our earlier paper, we demonstrate that the DSA provides a robust probe for both the quark and gluon OAM distributions within the proton. In contrast, we find that while the SSA is also sensitive to the OAM distributions, extraction of the latter from the SSA would require new developments in small- $x$ theory and phenomenology, and is probably not feasible at this point in time. These findings highlight the potential of DSA measurements in elastic dijet production at the future Electron-Ion Collider to provide the first-ever direct access to the quark and gluon OAM distributions at small $x$ , paving the way for new insights into the proton spin puzzle.
Comments:
39 pages, 4 figures; v2: typos corrected, discussion expanded, 40 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2410.21260 [pdf]
PRD(2025)·16 citations

Affiliations

first authorsco-authorsvia INSPIRE