Coupled-channels analysis of the 26Mg(p, p′) 26Mg reaction at 24.0 MeV

Abstract

Angular distributions from the 26Mg(p, p′) 26Mg reaction at E p = 23.95′ MeV have been measured with a split-pole magnetic spectrograph. The resolution obtained was 11–15 keV. Coupled-channels calculations have been performed for the 0 +, 2 + and 4 + members of the ground-state band and for the 2 +, 3 + and 4 + members of the lowest K π = 2 + and K π = 3 + bands. Calculations based on the rigid-rotator model yield no satisfactory descriptions. Much better results are obtained when the coupling strengths between the various states are allowed to be different from the values given by the rigid-rotator model. The results obtained from this analysis were used together with the results of electromagnetic studies to obtain the “true” proton and neutron transition matrix elements M p(E2) and M n(E2) for a number of L = 2 transitions between the low-lying states of 26Mg. A comparison of the result found for M n(E2; 2 2 + → 0 1 +) with the value for M p(E2; 2 2 + → 0 1 +) in the mirror nucleus 26Si as found from γ-ray studies shows a good agreement. The results for M p(E2), M n(E2) and for the transition matrix elements of the lowest four 4 + → 0 + 1 transitions have been compared to the results of shell-model calculations within the full (1s0d) shell. A satisfactory agreement is found, when effective charges consistent with the predictions of the schematic model of Brown and Madsen are used.