The Mixing Ratio of the (p3/2)−1 → (p1/2)−1 Transition in 15O

Abstract

The mixing ratio of the 3/2− → 1/2−, 6.18 → 0 MeV transition in 15O has been measured using the 14N(p,γγ)15O reaction. The value obtained is −0.141 ± 0.016, confirming previous indications that this mixing ratio is a factor of two larger than is predicted by shell-model calculations which give values consistent with experiment for the corresponding transition in 15N. The discrepancy may be due to uncertainties in the contributions to the E2 strength from the 16O core and to the effect of different thresholds for nucleon emission in the two nuclei. The analysis of the present experiment necessitated a reevaluation of available data regarding M2 strengths in the 1p shell.