Nuclear Theory·nucl-th

Thursday·June 6, 2024

7 papers—4 primary·3 cross-listed

01
[Submitted on 5 Jun 2024]
Effects of pairing strength on the nuclear structure and double- $β$ decay predictions within the mapped interacting boson model
Kosuke Nomura🇯🇵
The low-energy nuclear structure and two-neutrino double- $β$ ( $2 ν β β$ ) decay are studied within the interacting boson model (IBM) that is based on the nuclear energy density functional (EDF). The IBM Hamiltonian describing the initial and final even-even nuclei, and the interacting boson fermion-fermion Hamiltonian producing the intermediate states of the neighboring odd-odd nuclei are determined by the microscopic inputs provided by the self-consistent mean-field (SCMF) calculations employing a relativistic EDF and a separable pairing force. Sensitivities of the low-lying structure and $2 ν β β$ -decay properties to the pairing strength are specifically analyzed. It is shown that the SCMF calculations with decreased and increased pairing strengths lead to quadrupole-quadrupole interaction strengths in the IBM that are, respectively, significantly enhanced and reduced in magnitude. When the increased pairing is adopted, in particular, the energy levels of the excited $0^{+}$ states are lowered, and the predicted $2 ν β β$ -decay nuclear matrix elements (NMEs) increase in magnitude systematically. The mapped IBM employing the increased pairing force generates effective NMEs and half-lives that are in a reasonable agreement with the experimental data for the $^{76}$ Ge $\to^{76}$ Se, $^{82}$ Se $\to^{82}$ Kr, and $^{100}$ Mo $\to^{100}$ Ru decays in particular, whereas the calculation with the standard pairing strength is adequate to provide an overall good description of the effective NMEs in agreement with data.
Comments:
22 pages, 13 figures, 8 tables
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2406.02986 [pdf]
PRC(2024)·8 citations
02
[Submitted on 5 Jun 2024]
Study of hybrid stars with nonstrange quark matter cores
Cheng-Ming Li🇨🇳 · He-Rui Zheng🇨🇳 · Shu-Yu Zuo🇨🇳 · Ya-Peng Zhao🇨🇳 · Fei Wang🇨🇳 · Yong-Feng Huang🇨🇳
In this work, under the hypothesis that quark matter may not be strange (Holdom et al. 2018), we adopt a modification of the coupling constant of the four-quark scalar interaction $G \to G_{1} + G_{2} ⟨ ψ ˉ ψ ⟩$ in the 2-flavor Nambu-Jona-Lasinio (NJL) model to study nonstrange hybrid stars, where $G_{1}$ and $G_{2}$ are two parameters constrained by using the lattice QCD simulation results at the critical temperature and zero chemical potential. The Maxwell construction is used to describe the first-order confinement-deconfinement phase transition in hybrid stars. With recent measurements on neutron star mass, radius, and tidal deformability, the hybrid equation of states are constrained. It is found that pure nonstrange quark matter cores can exist in hybrid stars, possessing $0.026 - 0.04$ solar mass. The maximum hybrid star mass in the framework of the modified NJL model is about 0.1 solar mass lighter than that in the conventional 2-flavor NJL model. It is argued that the binary neutron stars in GW170817 should be hadron stars.
Comments:
13 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2406.03211 [pdf]
ApJ(2025)·5 citations
03
[Submitted on 5 Jun 2024]
Inhomogeneous SU(2) gluon matter under rotation
Yin Jiang🇨🇳
In this work a rotating SU(2) gluon system have been studied with the dyon ensemble in dilute limit. By solving the rotation-modified Yang-Mills equation we have obtained rotational corrections to the so-called dyon solutions with arbitrary centers to $O (ω^{2})$ order and the corresponding semi-classical potential. The radial position dependent deconfinement temperature have been obtained by minimizing the semi-classical potential in both real and imaginary angular velocity cases. Although without the $ω$ -dependent coupling constant the critical temperature behaves different from the lattice simulation at each radial position as the rotation goes faster, its radial dependence is qualitatively the same as the lattice. That is in the real velocity case the outer layer will deconfine more difficult while the reverse is true in the imaginary velocity case.
Comments:
9 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
arXiv:
2406.03311 [pdf]
PRD(2024)·12 citations
04
[Submitted on 5 Jun 2024]
Use of quantality in nuclei and many-body systems
J.-P. Ebran🇫🇷 · L. Heitz🇫🇷 · E. Khan🇫🇷
The use of quantality is discussed in the case of nuclei and other many-body systems such as atomic electrons. This dimensionless quantity is known to indicate when a many-body system behaves like a crystal or a quantum liquid. Its role is further analyzed by showing its relation to the scattering length. The emergence of a fundamental lengthscale, the limit radius, is also shown. It corresponds to the hard-core of the nucleon-nucleon interaction in the case of nucleons, and to a value close to the Bohr radius in the case of atomic electrons. The occurrence of a cluster phase in nuclei is analyzed using the quantality through its relation to the localization parameter, allowing for the identification of both the number of nucleons and the density as control parameters for the occurrence of this phase. The relation of the quantality to the magnitude of the interaction also exhibits a third dimensionless parameter, monitoring the magnitude of the spin-orbit effect in finite systems, through the realization of the pseudo-spin symmetry. The impact of quantality on the spin-orbit effect is compared in various many-body systems. The role of quantality in the relative effect of the binding energy and the shell one is also analyzed in nuclei. Finally, additional dimensionless quantities are proposed from the generalization of the quantality. Nuclei are found to be exceptional systems because all their dimensionless quantities are close to the order of unity, at variance with other many-body systems.
Comments:
13 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2406.03378 [pdf]
PRC(2024)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE

Effects of pairing strength on the nuclear structure and double-β decay predictions within the mapped interacting boson model

Study of hybrid stars with nonstrange quark matter cores

Inhomogeneous SU(2) gluon matter under rotation

Use of quantality in nuclei and many-body systems

Affiliations

Effects of pairing strength on the nuclear structure and double- $β$ decay predictions within the mapped interacting boson model