Proton dominance in the 2^+_2 -> 0^+_1 transition of N = Z\pm 2 nuclei around Si-28

TL;DR

This paper investigates E2 transitions in Si-30 and related nuclei, revealing proton dominance in specific transitions due to oblate proton structures, using antisymmetrized molecular dynamics and mirror analysis.

Contribution

It introduces a detailed analysis of proton and neutron transition matrix amplitudes in mirror nuclei, highlighting the proton dominance linked to oblate proton shapes in Si isotopes.

Findings

Proton dominance observed in the 2^+_2 -> 0^+_1 transition of Si-30.

M_n/M_p ratio indicates proton dominance due to oblate proton structure.

Mirror analysis elucidates the role of proton-neutron asymmetry in transition strengths.

Abstract

E2 transitions in Si-30 are investigated in relation with intrinsic deformations based on a method of antisymmetrized molecular dynamics. By comparing E2 transition strengths in the mirror nuclei Si-30 and S-30, transition matrix amplitudes M_p and M_n for protons and neutrons are discussed in mirror analysis. Particular attention is paid to the M_n/M_p ratio in the transition from the 2^+_2 state to the 0^+_1 state. The M_n/M_p ratio in Mg-26 and Si-26 is also investigated. It is found that the proton dominance in the transition 2^+_2 -> 0^+_1 in Si-30 and Si-26 originates in the oblate trend of the Z=14 proton structure.