Isospin mixing in 12C

Abstract We observe a yield to the 1 + T = 1 level in 12 C at 15.11 MeV in the isospin forbidden 12 C(d, d') and 10 B(α, d) reactions at about 1 % of the yield to the 1 + T = 0 level at 12.71 MeV. Observed yields to the T = 12 + level at 16.11 MeV in both reactions at about half the yield to the 15.11 MeV level preclude attributing this observed isospin violation entirely to final state mixing. From the ratios of the spectroscopic factors for the 12.71 and 15.11 MeV levels in 12 C and the ground state of 12 B from the 13 C(d, t) and 13 C(d, 3 He) reactions, we find a charge dependent matrix element between the 1 + states in 12 C of 179 ± 75 keV.