Interference term between the spin and orbital contributions to M1 transitions - art. no. 024308

We study the cross-correlation between the spin and orbital parts of magnet ic dipole transitions M1 in both isoscalar and isovector channels. In parti cular, we closely examine certain cases of isovector transitions where Sigm a B(M1) is very close to Sigma B(M1)(sigma) + Sigma B(M1)(iota), implying a cancellation of the summed interference terms. We gain some insight into t his problem by considering special cases approaching the SU(4) limit, and b y examining the behavior of single-particle transitions at the beginning an d towards the end of the s - d shell. For isoscalar transitions there is al ways destructive interference between the spin and orbital amplitudes.