Abstract

Since 1956, fourteen experimentally-deduced values of the Fermi to Gamow-Teller mixing ratio y = C v M F /C A M GT were published, varying from 0.05 to —0.36 with most values consistent with y = 0, particularly those from recent measurements. Our calculation, using the Nilsson model, yields >> = 2.07 x 10 ~ 4 , which can be taken as zero. Our result is therefore consistent with time-reversal invariance. Furthermore, the vanishing value of y arises both from the AT selection rule and the AK selection rule.