Nuclear Theory·nucl-th

Thursday·February 15, 2024

10 papers—2 primary·8 cross-listed

01
Indispensability of cross-shell contributions in neutron resonance spacing
T. Ghosh · Sangeeta · B. Maheshwari · G. Saxena · B. K. Agrawal
Spin and parity dependent nuclear level densities (NLDs) are obtained for configuration interaction shell model using a numerically efficient spectral distribution method. The calculations are performed for $^{24}$ Na, $^{25, 26, 27}$ Mg nuclei using full $s d$ - $p f$ model space that incorporates the cross-shell excitations from $s d$ to $p f$ -shell. The NLDs so obtained are then employed to determine the s-wave neutron resonance spacing (D $_{0}$ ) which is one of the crucial inputs for the predictions of astrophysical reaction rates. Though the considered nuclei are not neutron-rich, the contributions from cross-shell excitations to $p f$ -shell are indispensable to explain the experimental data for D $_{0}$ which otherwise are significantly overestimated.
nucl-thJ.Phys.G(2024)·0 citations
02
Understanding the mirror asymmetry in Gamow-Teller transition rates between $^{28}$ Al( $β^{-}$ ) $^{28 m}$ Si and $^{28}$ P( $β^{+}$ ) $^{28 m}$ Si
L. Xayavong🇰🇷 · N. A. Smirnova🇫🇷 · Y. Lim🇰🇷
The long-standing discrepancy between shell-model and experimental values of the mirror asymmetry in Gamow-Teller transition rates for $^{28}$ Al( $β^{-}$ ) $^{28 m}$ Si and $^{28}$ P( $β^{+}$ ) $^{28 m}$ Si is partially resolved by integrating the $p$ -orbital contribution into the radial mismatch correction term. This approach offers a potential estimate of the radial mismatch-induced core-orbital contribution based on the French-Macfarlane sum rules, avoiding the need for heavy calculations required by the first-principle shell model. Additionally, the isospin-mixing contribution undergoes considerable improvement through scaling the calculated isospin-mixing correction with the experimental energy separation between the lowest two admixed states, in accordance with the result from the two-level model.
nucl-thnucl-exPRC(2024)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE

Indispensability of cross-shell contributions in neutron resonance spacing

Understanding the mirror asymmetry in Gamow-Teller transition rates between 28Al(β−)28mSi and 28P(β+)28mSi

Affiliations

Understanding the mirror asymmetry in Gamow-Teller transition rates between $^{28}$ Al( $β^{-}$ ) $^{28 m}$ Si and $^{28}$ P( $β^{+}$ ) $^{28 m}$ Si