Nuclear structure properties and weak interaction rates of even-even Fe isotopes

TL;DR

This study investigates the nuclear structure and weak interaction rates of neutron-rich even-even Fe isotopes using IBM1 and pnQRPA models, highlighting the impact of nuclear deformation on stellar weak rates with potential astrophysical implications.

Contribution

It introduces a combined use of IBM1 and pnQRPA models to analyze deformation effects on weak interaction rates of Fe isotopes, providing new insights into their astrophysical relevance.

Findings

Larger deformation reduces weak interaction rates.

Stellar rates are up to 10,000 times smaller than previous estimates.

Nuclear deformation significantly influences weak interaction calculations.

Abstract

Nuclear structure properties and weak interaction rates of neutron rich even even iron (Fe) isotopes (A = 50 70) are investigated using the Interacting Boson Model1 (IBM1) and the proton neutron Quasiparticle Random Phase Approximation (pnQRPA) model. The IBM1 is used for the calculation of energy levels and the B(E2) values of neutron rich Fe isotopes. Later their geometry was predicted within the potential energy formalism of the IBM1 model. Weak interaction rates on neutron rich nuclei are needed for the modeling and simulation of presupernova evolution of massive stars. In the current study, we investigate the possible effect of nuclear deformation on stellar rates of even even Fe isotopes. The pnQRPA model is applied to calculate the weak interaction rates of selected Fe isotopes using three different values of deformation parameter. It is noted that, in general, bigger deformation values led to smaller total strength and larger centroid values of the resulting Gamow Teller distributions. This later translated to smaller computed weak interaction rates. The current finding warrants further investigation before it may be generalized.The reported stellar rates are up to 4 orders of magnitude smaller than previous calculations and may bear astrophysical significance.