Nuclear Theory·nucl-th

Tuesday·August 8, 2023

20 papers—11 primary·9 cross-listed

01
[Submitted on 3 Aug 2023]
Radiative neutron capture reaction rates for stellar nucleosynthesis
Vinay Singh · Debasis Bhowmick · D. N. Basu
There is a high demand for nuclear data in multidisciplinary subject like nuclear astrophysics. The two areas of nuclear physics which are most clearly related to one another are stellar evolution and nucleosynthesis. The necessity for nuclear data for astrophysical applications puts experimental methods as well as reliability and predicative ability of current nuclear models to the test. Despite recent, considerable advances, there are still significant issues and mysteries. Only a few characteristics of nuclear astrophysics are covered in the current work which include $^{20}$ Ne(n, $γ$ ) $^{21}$ Ne, $^{52}$ Fe(n, $γ$ ) $^{53}$ Fe, $^{53}$ Fe(n, $γ$ ) $^{54}$ Fe, $^{54}$ Fe(n, $γ$ ) $^{55}$ Fe and $^{55}$ Fe(n, $γ$ ) $^{56}$ Fe reactions which are important in stellar nucleosynthesis. The reaction rates are calculated using nuclear statistical model. These rates are subsequently fitted to polynomials of temperature T $_{9}$ in order to facilitate calculations for stellar nucleosynthesis.
Comments:
7 pages including 5 figures and 2 tables
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
2308.02579 [pdf]
Indian J.Phys.(2025)·0 citations
02
[Submitted on 4 Aug 2023]
Triplet-odd pairing in finite nuclear systems: Even-even singly closed nuclei
Nobuo Hinohara · Tomohiro Oishi · Kenichi Yoshida
Background: The appearance of the pairing condensate is an essential feature of many-fermion systems. There are two possible types of pairing: spin-singlet and spin-triplet. However, an open question remains as to whether the spin-triplet pairing condensate emerges in finite nuclei. Purpose: The aim of this work is to examine the coexistence of the spin-singlet and spin-triplet like-particle pairing condensates in nuclei. We also discuss the dependence on the type of pairing functional. Method: The Hartree-Fock-Bogoliubov calculations with a Skyrme $+$ local-pair energy-density functional (EDF) are performed to investigate the pairing condensate in the spherical ground states of Ca and Sn isotopes. Results: The spin-singlet pair EDF induces not only the spin-singlet but also the spin-triplet pairing condensates due to a strong spin-orbit splitting. By discarding the spin-orbit EDF, only the spin-singlet pairing condensate appears. The spin-triplet pair EDF, however, induces the spin-orbit splitting and accordingly the spin-singlet pairing condensate. Conclusions: The spin-orbit splitting plays an essential role in the coexistence of the spin-singlet and spin-triplet pairing condensates in nuclei.
Comments:
9 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th); Superconductivity (cond-mat.supr-con)
arXiv:
2308.02617 [pdf]
PRC(2024)·11 citations
03
[Submitted on 4 Aug 2023]
Neutron matter: The unitary limit and its far-reaching impact
Francesca Sammarruca
We explore low-density neutron matter and its behavior in proximity to the unitary limit. To that end, we construct unitary nucleon-nucleon potentials with infinite 1S0 neutron-neutron scattering lengths. We discuss the Berstch parameter in relation to results from ultra-cold atomic gases. Unitarity as a constraint for neutron matter and the symmetry energy has been discussed in the literature. We revisit some of those arguments and emphasize the relevance of keeping a firm link with low-energy nuclear physics for robust predictions of neutron-rich systems. Our predictions are obtained from realistic few-nucleon forces based on chiral effective field theory at N3LO.
Comments:
10 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2308.02745 [pdf]
PRC(2023)·2 citations
04
[Submitted on 5 Aug 2023]
Candidates for three-quasiparticle $K$ -isomers in odd-even Md-Rg nuclei
P. Jachimowicz · M. Kowal · J. Skalski
We performed a search for three-quasiparticle high- $K$ isomer candidates in odd-even Md - Rg nuclei by considering the lowest lying 1 $π$ 2 $ν$ and 3 $π$ excitations. Our approach involves calculating the energies of different nuclear configurations using a microscopic-macroscopic model with the Woods-Saxon potential. We explore three pairing scenarios: blocking, quasi-particle BCS method, and particle number projection formalism. The optimal deformations for both ground-states and high- $K$ configurations are determined through a four-dimensional energy minimization process. By analyzing the obtained excitation energies, we discuss the most promising candidates for high- $K$ isomers and compare them, where possible, with existing experimental data. We also discuss a possible isomer $α$ -decay hindrance using calculated $Q_{α}$ -hindrances.
Comments:
Submitted to PRC
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2308.02893 [pdf]
PRC(2023)·2 citations
05
[Submitted on 6 Aug 2023]
The charge and mass symmetry breaking in the $K K K ˉ$ system
Igor Filikhin🇺🇸 · Roman Ya. Kezerashvili🇺🇸 · Branislav Vlahovic🇺🇸
In the framework of the Faddeev equations in configuration space, we investigate the $K$ (1460) meson as a resonant state of the $K K K ˉ$ kaonic system. We perform calculations for the particle configurations $K^{0} K^{+} K^{-}$ and $K^{0} K^{+} K^{0}$ within two models: the $A B C$ model, in which all three particles are distinguishable, and the $AA C$ model when two particles are identical. The models differ in their treatment of the kaon mass difference and the attractive Coulomb force between the $K^{+} K^{-}$ pair. We found that the Coulomb shift adds over 1 MeV to the three-body binding energy. The expected correction to the binding energy due to mass redistribution from $AA$ to $A B$ is found to be negligible, up to a maximum of 6\% of the relative mass correction. At the same time, the symmetry of the wave function is distorted depending on the mass ratio value. We found that the repulsive $K K$ interaction plays essential role in the binding energy of the $K K K ˉ$ system and report the mass of 1461.8 or 1464.1 MeV for the neutral $K^{0}$ (1460) and 1466.5 or 1468.8 MeV for the charged $K^{+}$ (1460) resonances, respectively, depending on the parameter sets for $K K$ and $K K ˉ$ interactions.
Comments:
13 page, 4 figures
Subjects:
Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2308.02980 [pdf]
J.Phys.G(2024)·9 citations
06
[Submitted on 6 Aug 2023]
Effect of cluster transfer on neutron-rich nuclide production around N=126 in multinucleon transfer reactions
Zhao-Qing Feng
The cluster transfer in multinucleon transfer reactions near Coulomb barrier energies is implemented into the master equations in dinuclear system model, in which the deuteron, triton, $^{3}$ He and $α$ are taken into account. The effects of cluster transfer and dynamical deformation on the formation of primary and secondary fragments are systematically investigated. It is found that the inclusion of cluster transfer is favorable the fragment formation with increasing the transferring nucleons and leads to a broad mass distribution. The isotopic cross sections of elements W, Os, Rn and Fr in the reaction of $^{136}$ Xe+ $^{208}$ Pb at the incident energy of E $_{c . m .}$ = 450 MeV are nicely consistent with the Argonne data. The new neutron-rich isotopes of wolfram and osmium are predicted with cross sections above 10 nb. The production mechanism of neutron-rich heavy nuclei around N = 126 in the reactions of $^{58, 64, 72}$ Ni + $^{198}$ Pt is investigated thoroughly. The cross sections for producing the neutron-rich isotopes of platinum, iridium, osmium and rhenium in the multinucleon transfer reactions of $^{64}$ Ni + $^{198}$ Pt and $^{72}$ Ni + $^{198}$ Pt at the center of mass energies of 220 MeV and 230 MeV are estimated and proposed for the future experiments.
Comments:
10 pages, 6 figures. arXiv admin note: text overlap with arXiv:2108.13598
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2308.03127 [pdf]
PRC(2023)·10 citations
07
[Submitted on 6 Aug 2023]
Cluster radioactivity from trans-tin to superheavy region using an improved empirical formula
G. Saxena · A. Jain
A simple relation $(a Z_{c} + b) (Z_{d} / Q)^{1/2} + (c Z_{c} + d)$ of estimation of the half-life of cluster emission is further improved for cluster and $α$ -decays, separately, by incorporating isospin of parent nucleus as well as angular momentum taken away by the emitted particle. This improved version is not only found robust in producing experimental half-lives belonging to the trans-tin and trans-lead regions but also elucidates cluster emission in superheavy nuclei over the usual $α$ -decay. Considering daughter nuclei around the doubly magic $^{100}$ Sn and $^{208}$ Pb nuclei for trans-tin and trans-lead (including superheavy) parents, respectively, a systematic and extensive study of 56 $\leq$ Z $\leq$ 120 isotopes is performed for the light and heavy cluster emissions. A fair competition among cluster emission, $α$ -decay, spontaneous fission, and $β$ -decay is observed in this broad range resulting in a substantial probability of C to Sr clusters from several nuclei, which demonstrates the adequacy of shell effects. The present article proposes a single, improved, latest-fitted, and effective formula of cluster radioactivity that can be used to estimate precise half-lives for a wide range of the periodic chart from trans-tin to superheavy nuclei.
Comments:
12 pages, 2 Figures, 5 Tables, Accepted in European Physics Journal A
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2308.03180 [pdf]
EPJA(2023)·12 citations
08
[Submitted on 7 Aug 2023]
Probing the QCD phase transition with chiral mixing in dilepton production
Azumi Sakai🇯🇵 · Masayasu Harada🇯🇵 · Chiho Nonaka🇯🇵 · Chihiro Sasaki🇯🇵 · Kenta Shigaki🇯🇵 · Satoshi Yano🇯🇵
We perform a systematic study of dilepton emission in a hot QCD medium based on three different scenarios of chiral mixing, each of which yields a characteristic structure in the vector spectral function. The in-medium spectral functions are accommodated into the state-of-the-art hydrodynamic simulations for a relativistic viscous fluid to calculate the dilepton production rate, fully accounting for the space-time evolution of a created fireball in relativistic heavy-ion collisions. We demonstrate that the low-temperature theorem of chiral mixing extrapolated toward a chiral crossover, often used in the literature, leads to critical shortcomings: the inadequacy of width broadening, and a substantial overestimate of the dilepton yield maximized around the invariant mass of $M = 1.2$ GeV. The proper prescription offers a milder yet sizable increase in the window of $1.1 < M < 1.4$ GeV as the direct signature of chiral symmetry restoration.
Comments:
6 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2308.03305 [pdf]
3 citations
09
[Submitted on 7 Aug 2023]
Relativistic model-free prediction for neutrinoless double beta decay at leading order
Y. L. Yang🇨🇳 · P. W. Zhao🇨🇳
Starting from a manifestly Lorentz-invariant chiral Lagrangian, we present a model-free prediction for the transition amplitude of the process $nn \to pp e^{-} e^{-}$ induced by light Majorana neutrinos, which is a key process of the neutrinoless double beta decay ( $0 ν β β$ ) in heavy nuclei employed in large-scale searches. Contrary to the nonrelativistic case, we show that the transition amplitude can be renormalized at leading order without any uncertain contact operators. The predicted amplitude defines a stringent benchmark for the previous estimation with model-dependent inputs, and greatly reduces the uncertainty of $0 ν β β$ transition operator in the calculations of nuclear matrix elements. Generalizations of the present framework could also help to address the uncertainties in $0 ν β β$ decay induced by other mechanisms. In addition, the present work motivates a relativistic {\it ab initio} calculation of $0 ν β β$ decay in light and medium-mass nuclei.
Comments:
8 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2308.03356 [pdf]
PLB(2024)·15 citations
10
[Submitted on 7 Aug 2023]
Sensitivity study of mirror energy differences in positive parity bands of T=3/2 A=45 nuclei
W. Satula · M. A. Bentley · A. Jalili · S. Uthayakumaar
Symmetry conserving density functional theory (DFT) based no-core-configuration-interaction framework (DFT-NCCI) is an excellent tool for precision calculation of diverse (pseudo-)observables related to isospin symmetry breaking from elusive isospin impurities trough isospin corrections to superallowed beta decays to mirror- and triplet-displacement energies and mirror energy differences (MED) along rotational bands. In our recent work [Phys. Rev. C {\bf 106}, 024327 (2022)] we performed axial DFT-NCCI calculations and failed to reproduce a sign of MED in positive-parity bands of 45Sc/45Cr T=3/2 mirror pair what casts a shadow on credibility of the model. In this work we aim to perform a thorough analysis of this case with the focus on sensitivity of our predictions with respect to: (i) low-energy constants (LECs) of our effective contact charge symmetry breaking (CSB) force and (ii) nuclear shape. We demonstrate, among the other, that inclusion of triaxial positive-parity ground-state - which is actually the global positive-parity minimum in our unconstrained mean-field calculation - in the DFT-NCCI calculations instead of the axial one used before leads to MED which are consistent with experimental data concerning both their sign as well as magnitude without any need for fine-tuning of the model's LECs.
Comments:
7 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2308.03505 [pdf]
PRC(2023)·5 citations
11
[Submitted on 7 Aug 2023]
Hexadecapole axial collectivity in the rare earth region, a beyond mean field study
C.V. Nithish Kumar · L. M. Robledo
Hexadecapole collectivity and its interplay with quadrupole degrees of freedom is studied in an axial symmetry preserving framework based on the Hartree Fock Bogoliubov (HFB) plus generator coordinate method (GCM). Results are obtained for several even-even isotopes of Sm and Gd with various parametrizations of the Gogny force. The analysis of the results indicates the strong coupling between the quadrupole and hexadecapole degrees of freedom. The first two excited states are vibrational in character in most of the cases. The impact of prolate-oblate shape mixing in the properties of hexadecapole states is analyzed.
Comments:
10 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2308.03650 [pdf]
PRC(2023)·16 citations

Affiliations

first authorsco-authorsvia INSPIRE