Nuclear Theory·nucl-th

Wednesday·January 19, 2022

26 papers—10 primary·16 cross-listed

01
[Submitted on 14 Jan 2022]
$Υ$ and $η_{b}$ nuclear bound states
J. J. Cobos-Martínez🇲🇽 · G. N. Zeminiani🇧🇷 · K. Tsushima🇧🇷
$Υ$ and $η_{b}$ nuclear bound state energies are calculated for various nuclei neglecting any possible effects of the widths. Essential input for the calculations, namely the medium-modified $B$ and $B^{*}$ meson masses, as well as the density distributions in nuclei, are calculated within the quark-meson coupling (QMC) model. The attractive potentials for the $Υ$ and $η_{b}$ mesons in nuclei are calculated from the mass shifts of these mesons in nuclear matter in the local density approximation. These potentials originate from the in-medium enhanced $B B$ and $B B^{*}$ loops in their respective self energy. After an extensive analysis we conclude that our results suggest that the $Υ$ and $η_{b}$ mesons should form bound states with all the nuclei considered.
Comments:
10 pages, 6 figures, 2 tables
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2201.05696 [pdf]
PRC(2022)·15 citations
02
[Submitted on 15 Jan 2022]
Erosion of N = 28 shell closure: Shape coexistence and monopole transition
Y. Suzuki🇯🇵 · W. Horiuchi🇯🇵 · M. Kimura🇯🇵
Background: In neutron-rich nuclei neighboring 42Si, the quenching of the N = 28 shell gap occurs and is expected to induce the shape coexistence in their excitation spectra. Purpose: We show that different nuclear shapes coexist in N = 28 isotones 40Mg, 42Si, and 44S, and investigate observables to probe it. Method: Antisymmetrized molecular dynamics with Gogny D1S density functional is applied to describe the shape coexistence phenomena without ad hoc assumption of the nuclear shape. Results: We find that rigid shapes with different deformations coexist in the ground and the first excited 0+ states of 40Mg and 42Si, while in 44S the states exhibit large-amplitude collective motion, which does not have any particular shape. These characteristics are reflected well in the monopole transition strengths. Conclusion: The quenching of the N = 28 shell gap leads to the unique shape coexistence in the N = 28 isotones, which can be probed by the monopole transition strengths.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2201.05731 [pdf]
PTEP(2022)·9 citations
03
[Submitted on 15 Jan 2022]
Two-proton emission systematics
D.S. Delion · S.A. Ghinescu
The simultaneous emission of two protons is an exotic and complex three-body process. It is very important for experimental groups investigating the nuclear stability on the proton drip line to have a simple rule predicting the two-proton decay widths with a reasonable accuracy for transitions between ground as well as excited states in terms of relevant physical variables. In spite of its complexity, we show that the two-proton emission process obeys similar rules as for binary emission processes like proton, alpha and heavy cluster decays. It turns out that the logarithm of the decay width, corrected by the centrifugal barrier, linearly depends upon the Coulomb parameter within one order of magnitude. On the other hand, the universal linear dependence with a negative slope between the logarithm of the reduced width and the fragmentation potential, valid for any kind of binary decay process, is also fulfilled for the two-proton emission with a relative good accuracy. As a consequence of pairing correlations the two protons are simultaneously emitted from a singlet paired state. We evidence that indeed one obtains a linear dependence between the logarithm of the reduced width and pairing gap within a factor of two, giving a good predictive power to this law. It turns out that the diproton and alpha-cluster formation probabilities have similar patterns versus the pairing gap, while in the one-proton case one has a quasi-constant behavior.
Comments:
5 pages, 4 figures, 2 tables, 36 references
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2201.05814 [pdf]
PRC(2022)·10 citations
04
[Submitted on 15 Jan 2022]
Pairing effects on vorticity of incident neutron current at quasiparticle resonance energies in $n$ - $A$ elastic scattering
K. Mizuyama · H. Dai Nghia · T. Dieu Thuy · N. Hoang Tung · T. V. Nhan Hao
In this study, we analyzed how the incident neutron current is affected by the pairing effect in the neutron-nucleus scattering described within the framework of Hartree-Fock-Bogoliubov theory by performing numerical calculations in terms of current, vorticity, and circulation of the incident neutron current. We found that the pairing effect on the incident neutron flux is completely different between particle-type and hole-type quasiparticle resonances. In the case of h-type quasiparticle resonance, the pairing acts to prevent the neutron flux from entering the nucleus, reducing circulation. In the case of p-type quasiparticle resonance, pairing acts to reduce circulation at energies lower than the resonance energy, but at energies higher than the resonance energy, the effect of pairing on the neutron flux is reversed and, conversely, circulation is increased.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2201.05824 [pdf]
PRC(2022)·0 citations
05
[Submitted on 15 Jan 2022]
Shape Coexistence in 74Ge, 74Se and 74Kr Investigated by Phenomenological and Microscopic Models
A. Ait Ben Mennana · R. Benjedi · P. Buganu · R. Budaca · A. I. Budaca · Y. EL Bassem · A. Lahbas · M. Oulne
The deformation properties of 74Ge, 74Se and 74Kr are studied within the phenomenological Bohr-Mottelson model, having as input the experimental collective energy states, as well with Covariant Density Functional theories based on microscopic structural information. The results of these approaches are shown to be compatible in what concerns the presence of coexisting shapes in the considered nuclei, while the emergence of shape mixing is deduced from the phenomenological calculated collective states.
Comments:
10 pages
Subjects:
Nuclear Theory (nucl-th); Atomic Physics (physics.atom-ph)
arXiv:
2201.05892 [pdf]
Bulg.J.Phys.(2021)·0 citations
06
[Submitted on 16 Jan 2022]
Angular momentum and parity projected multidimensionally constrained relativistic Hartree-Bogoliubov model
Kun Wang · Bing-Nan Lu
The nuclear deformations are of fundamental importance in nuclear physics. Recently we developed a multi-dimensionally constrained relativistic Hartree-Bogoliubov (MDCRHB) model, in which all multipole deformations respecting the $V_{4}$ symmetry can be considered self-consistently. In this work we extend this model by incorporating the angular momentum projection (AMP) and parity projection (PP) to restore the rotational and parity symmetries broken in the mean-field level. This projected-MDCRHB (p-MDCRHB) model enables us to connect certain nuclear spectra to exotic intrinsic shapes such as triangle or tetrahedron. We present the details of the method and an exemplary calculation for $^{12}$ C. We develop a triangular moment constraint to generate the triangular configurations consisting of three $α$ clusters arranged as an equilateral triangle. The resulting $^{12}$ C spectra are consistent with that from a triangular rigid rotor for large separations between the $α$ clusters. We also calculate the $B (E 2)$ and $B (E 3)$ values for low-lying states and find good agreement with the experiments.
Comments:
37 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2201.05953 [pdf]
Commun.Theor.Phys.(2022)·22 citations
07
[Submitted on 17 Jan 2022]
Differential elastic nucleus-nucleus scattering in complete Glauber theory
Yu.M. Shabelski🇷🇺 · A.G. Shuvaev🇷🇺
The differential elastic cross sections of $^{12}$ C -- $^{12}$ C and $^{11}$ Li -- $^{12}$ C nuclei are calculated in the complete Glauber theory. The role of the possible correlations connected to the shell effects in $^{11}$ Li nucleus is considered.
Comments:
9 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2201.06270 [pdf]
Mod.Phys.Lett.A(2022)·2 citations
08
[Submitted on 17 Jan 2022]
Single-pion contribution to the Gerasimov--Drell--Hearn sum rule and related integrals
Igor Strakovsky (GWU)🇺🇸 · Simon Širca (University of Ljubljana)🇸🇮 · William J. Briscoe (GWU)🇺🇸 · Alexandre Deur (JLab)🇺🇸 · Axel Schmidt (GWU)🇺🇸 · Ron L. Workman (GWU)🇺🇸
Phenomenological amplitudes obtained in partial-wave analyses (PWA) of single-pion photoproduction are used to evaluate the contribution of this process to the Gerasimov-Drell-Hearn (GDH), Baldin and Gell-Mann-Goldberger-Thirring (GGT) sum rules, by integrating up to 2 GeV in photon energy. Our study confirms that the single-pion contribution to all these sum rules converges even before the highest considered photon energy, but the levels of saturation are very different in the three cases. Single-pion production almost saturates the GDH sum rule for the proton, while a large fraction is missing in the neutron case. The Baldin integrals for the proton and the neutron are both saturated to about four fifths of the predicted total strength. For the GGT sum rule, the wide variability in predictions precludes any definitive statement.
Comments:
12 pages, 7 figure, 3 tables; discussion refined, references added, Minor fixes to the authorship list found during production; acknowledgement added; final version accepted by Phys Rev C
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2201.06495 [pdf]
PRC(2022)·12 citations
09
[Submitted on 18 Jan 2022]
$K^{-} d \to π Λ N$ reaction for studying charge symmetry breaking in the $Λ N$ interaction
Yutaro Iizawa🇯🇵 · Daisuke Jido🇯🇵 · Takatsugu Ishikawa🇯🇵
We discuss charge symmetry breaking in the $Λ N$ interaction. In order to investigate the $Λ p$ and $Λ n$ interactions at low energies, we propose to utilize the $K^{-} d \to π^{-} Λ p$ and $K^{-} d \to π^{0} Λ n$ reactions. They are symmetric under the exchange of both the pion and nucleon isospin partners in the final states. This advantage allows us to study charge symmetry breaking in the $Λ N$ interaction. We calculate the differential cross sections of these reactions with stopped kaons theoretically and discuss the possibility to extract the scattering length and effective range of the $Λ N$ scattering. With stopped kaons, the $Λ N$ interaction takes place dominantly in the spin-triplet state thanks to the deuteron spin and $s$ -wave dominance of the scattering amplitudes at the low energy. We find that the ratio of the differential cross sections as a function of the $Λ N$ invariant mass between the two reactions is useful for revealing how charge symmetry breaking, or isospin symmetry breaking appears in the low-energy $Λ N$ scattering.
Comments:
13 pages, 19 figures, 1table
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2201.06737 [pdf]
PRC(2022)·3 citations
10
[Submitted on 18 Jan 2022]
Dynamic density correlations in a baryon rich fluid using Mori-Zwanzig-Nakjima projection operator method
Guruprasad Kadam🇮🇳
In this work, we calculate the dynamic density correlations using Mori-Zwanzig-Nakajima projection operator method. With a judicious choice of slow variables we derive the evolution equations for these slow variables starting from generalised Langevin equation. We get the hydrodynamic form of density correlations function which consist of two acoustic peaks: also called Brillouin peaks, and one thermal peak: also called Rayleigh peak. We then estimate the dynamic density correlations near the critical point using critical exponents extracted from the statistical bootstrap model of hadronic matter. We find that the bulk viscosity contributes to the sound attenuation at leading order $\sim ∣ t ∣^{- \frac{5}{4}}$ while the thermal conductivity contribute at sub-leading order $\sim ∣ t ∣^{- \frac{3}{4}}$ . On the other hand, only the thermal conductivity contributes at leading order $\sim ∣ t ∣^{\frac{1}{4}}$ to the thermal diffusivity. We discuss the implications of these results in a search for the QCD critical point in the heavy-ion collision experiments.
Comments:
19 pages, 1 Captioned figure, Matches the published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
arXiv:
2201.06816 [pdf]
EPJC(2022)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE