J π = 1 + isospin doublet in 12C

Abstract

Isospin mixing in the J π = 1 + levels in 12C at 12.71 and 15.11 MeV has been studied by means of the 13C( 3He, α) 12C reaction. The relative α-particle and γ-ray decay widths were measured for both levels and the α-decay of the 15.11 MeV state was observed for the first time. Since the total width of the 12.71 MeV level is not known, these data have been used along with theoretical calculations to establish the isospin mixing of the two states. The intensity of isospin mixing is 1–3 %.