Nuclear Theory·nucl-th

Friday·July 17, 2020

9 papers—4 primary·5 cross-listed

01
[Submitted on 16 Jul 2020]
Excluded-volume model for quarkyonic matter II: Three-flavor shell-like distribution of baryons in phase space
Dyana C. Duarte🇺🇸 · Saul Hernandez-Ortiz🇺🇸 · Kie Sang Jeong🇺🇸
We extend the excluded-volume model of isospin symmetric two-flavor dense quarkyonic matter [Phys. Rev. C 101, 035201 (2020)] including strange particles and address its implications for neutron stars. The effective sizes of baryons are defined from the diverging hard-core potentials in the short interdistance regime. Around the hard-core density, the repulsive core between baryons at short distances leads to a saturation in the number density of baryons and generates perturbative quarks from the lower phase space, which leads to the shell-like distribution of baryons by the Pauli exclusion principle. The strange-quark Fermi sea always appears at high densities but the $Λ$ hyperon shell only appears when the effective size of the $Λ$ hyperon is smaller than the effective size of nucleons. We find that the pressure of strange quarkyonic matter can be large enough to support neutron stars with two times solar mass and can have a large sound speed, $c_{s}^{2} ≃ 0.7$ . The fraction of the baryon number carried by perturbative quarks is about 30% at the inner core of most massive neutron stars.
Comments:
17 pages, 5 figures, typographical and grammatical errors are corrected
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2007.08098 [pdf]
PRC(2020)·35 citations
02
[Submitted on 16 Jul 2020]
Second-forbidden nonunique $β^{-}$ decays of $^{24}$ Na and $^{36}$ Cl assessed by the nuclear shell model
Anil Kumar · Praveen C. Srivastava · Joel Kostensalo · Jouni Suhonen
We have performed a systematic study of the log $f t$ values, shape factors and electron spectra for the second-forbidden nonunique $β^{-}$ decays of $^{24}$ Na $(4^{+}) \to^{24}$ Mg $(2^{+})$ and $^{36}$ Cl $(2^{+}) \to^{36}$ Ar $(0^{+})$ transitions under the framework of the nuclear shell model. We have performed the shell model calculations in the $s d$ model space, using more recent microscopic effective interactions such as Daejeon16, chiral N3LO, and JISP16. These interactions are derived from the no-core shell model wave functions using Okubo-Lee-Suzuki transformation.For comparison, we have also shown the results obtain from the phenomenological USDB interaction. To test the predictive power of these interactions first we have computed low-lying energy spectra of parent and daughter nuclei involved in these transitions. The computed results for energy spectra, nuclear matrix elements, log $f t$ values, shape factors, electron spectra and decomposition of the integrated shape factor are reported and compare with the available experimental data.
Comments:
11 pages. 4 figures, 5 tables
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2007.08122 [pdf]
PRC(2020)·36 citations
03
[Submitted on 16 Jul 2020]
Possibilities of direct production of superheavy nuclei with Z=112--118 in different evaporation channels
J. Hong · G. G. Adamian · N. V. Antonenko · P. Jachimowicz · M. Kowal
The production cross sections of heaviest isotopes of superheavy nuclei with charge numbers 112--118 are predicted in the $x n$ --, $p x n$ --, and $α x n$ --evaporation channels of the $^{48}$ Ca-induced complete fusion reactions for future experiments. The estimates of synthesis capabilities are based on a uniform and consistent set of input nuclear data. Nuclear masses, deformations, shell corrections, fission barriers, and decay energies are calculated within the macroscopic-microscopic approach for even-even, odd-Z, and odd-N nuclei. For odd systems, the blocking procedure is used. To find, the ground states via minimization and saddle points using Immersion Water flow technique, multidimensional deformation spaces, containing non-axially are used. As shown, current calculations based on a new set of mass and barriers, agree very well with experimentally known cross-sections, especially in the $3 n$ --evaporation channel. The dependencies of these predictions on the mass/fission barriers tables and fusion models are discussed. A way is shown to produce directly unknown superheavy isotopes in the $1 n$ -- or $2 n$ --evaporation channels. The synthesis of new superheavy isotopes unattainable in reactions with emission of neutrons is proposed in the promising channels with emission of protons ( $σ_{p x n} ≃ 10 - 200$ fb) and alphas ( $σ_{α x n} ≃ 5 - 500$ fb).
Comments:
Submitted to PLB
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2007.08325 [pdf]
PLB(2020)·18 citations
04
[Submitted on 16 Jul 2020]
Nucleon polarizabilities in covariant baryon chiral perturbation theory with explicit $Δ$ degrees of freedom
M. Thürmann🇩🇪 · E. Epelbaum🇩🇪 · A. M. Gasparyan🇩🇪 · H. Krebs🇩🇪
We compute various nucleon polarizabilities in chiral perturbation theory implementing the $Δ$ -full ( $Δ$ -less) approach up to order $ϵ^{3} + q^{4}$ ( $q^{4}$ ) in the small-scale (chiral) expansion. The calculation is carried out using the covariant formulation of $χ$ PT by utilizing the extended on-mass shell renormalization scheme. Except for the spin-independent dipole polarizabilities used to fix the values of certain low-energy constants, our results for the nucleon polarizabilities are pure predictions. We compare our calculations with available experimental data and other theoretical results. The importance of the explicit treatment of the $Δ$ degree of freedom in the effective field theory description of the nucleon polarizabilities is analyzed. We also study the convergence of the $1/ m$ expansion and analyze the efficiency of the heavy-baryon approach for the nucleon polarizabilities.
Comments:
67 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2007.08438 [pdf]
PRC(2021)·13 citations

Affiliations

first authorsco-authorsvia INSPIRE

Excluded-volume model for quarkyonic matter II: Three-flavor shell-like distribution of baryons in phase space

Second-forbidden nonunique β− decays of 24Na and 36Cl assessed by the nuclear shell model

Possibilities of direct production of superheavy nuclei with Z=112--118 in different evaporation channels

Nucleon polarizabilities in covariant baryon chiral perturbation theory with explicit Δ degrees of freedom

Affiliations

Second-forbidden nonunique $β^{-}$ decays of $^{24}$ Na and $^{36}$ Cl assessed by the nuclear shell model

Nucleon polarizabilities in covariant baryon chiral perturbation theory with explicit $Δ$ degrees of freedom