Suppression of elastic magnetic electron scattering form factors

Some recent experiments have reported a strong suppression of the M3 part of the elastic magnetic electron scattering in a number of light nuclei. We examine the effect of the first-order as well as second-order perturbative diagrams on the momentum-transfer dependence of the M1 and M3 form factors in the case of a closed f/sub 7/2/ shell plus a neutron employing realistic effective interactions. It is seen that the second-order diagrams play an important role in suppressing the M3 form factor around its first maximum by roughly a factor of three; the enhanced importance of second-order polarization effects arises partly from the fact that the ''dequenching'' resulting from the RPA-type graphs is quite small