The Discrepancy in the Fermi Matrix Elements of the Isospin-forbidden 4+ ? 4+ ß- Decay of 46Sc

Abstract

A large number of measurements have been made on the ')I-polarisation asymmetry coefficient A ~- y - for 4 + --+ 4 + --+ 2 + of the 46Sc --+ 46Ti decay. Presently, there are two adopted values of A yielding the Fermi nuclear matrix elements 1M F I = (0· 06 ~ g: 6~) xl 0 - 3 and (1 ·4 ± 0·3) x 10- 3, the latter being the more probable. Using a one-body spheroidal Coulomb potential with Nilsson wavefunctions, the theoretical value of M F is found to be 0·91 x 10 - 3 in good agreement with the experimental value of(I.4±0.3)xlO- 3.