Study of the M1 isovector strength in 28Si

Abstract

Inelastic electron scattering measurements up to 1.5 fm-1 of strong M1 transitions to the 10.900 MeV, 11.446 MeV and 12.330 MeV states in 28Si, which form the bulk of the 28Si M1 isovector giant resonance, have revealed striking differences in their transition form factors, and have allowed information on the configurations contributing to each transition to be deduced. Full 2s-1d shell model calculations have also shown large differences in the form factors of the lowest Jpi =1+, T=1 states, but do not agree, in detail, with the experimental data.