Shell model configurations in the 21+ state in 46Ca from a g-factor measurement

The g factor of the first excited 21+ state in 46Ca has been remeasured with better accuracy than previously obtained, g(21+,Ca46)=−0.26(6). The experiment utilized the transient field technique combined with Coulomb excitation in inverse kinematics. This result was analyzed in terms of shell model plus deformed core calculations. The positive g factors of the 21+ states in 42Ca and 44Ca suggest that the 21+ state wave functions require significant particle-hole excitations of the Z=20, N=20 core. The new data for 46Ca show that (fp)ν6 configurations dominate near the shell closure at 48Ca and indicate that core excitation plays a lesser role than was hitherto believed.