, in a Nuclear Medium
An interesting feature of the axial weak interaction in nuclei is that relativistic invariance breaks down due to the stationary nucleus. Experiments indicate that the space part is reduced from its free space value of 1.26, whereas the time part is enhanced. Considerable attention has focused on the space part. The time part increase has been ascribed primarily to exchange currents. We are examining the effect of the Pauli exclusion principle on the time component. Preliminary indications are that a further increase occurs due to this effect.