Extended M1 Sum Rule for Mixed-Symmetry States

Abstract

A generalized M 1 sum rule for orbital magnetic dipole strength from excited symmetric states to mixed-symmetry states is considered within the protonneutron interacting boson model of even-even nuclei. Analytic expressions for the dominant terms in the B(M 1) transition rates from the 2 + 1,2 states are derived in the U(5) and SO(6) dynamic symmetry limits of the model, and the applicability of a sum rule approach is examined at and in-between these limits. Lastly, the sum rule is applied to the new data on mixed-symmetry states of 94 Mo and a quadrupole d-boson ratio n d (0 + 1 )/n d (2 + 2 ) ≈ 0.6 is obtained in a largely parameter-independent way.