Inelastic electron scattering, fine structure of M1 giant resonances and Gamow-Teller states

Recent progress in obtaining detailed fine structure distributions of magnetic giant resonances in nuclei using high resolution inelastic electron scattering at low energy is discussed. Specific examples chosen are the medium heavy nuclei 40424448Ca in which M1 excitations are due to neutron spin-flip transitions and the N=28 isotones 50Ti, 52Cr and 54Fe where in addition also proton excitations contribute to the measured M1 strength. It is found that the M1 strength is very fragmented and considerably quenched in comparison to predictions of shell model calculations in a model space that includes up to 2p-2h excitations. Finally, the old problem of M1 strength in 208Pb is revisited and the results of a form factor measurement of a recently discovered low lying Jsup(π)=1+ state by nuclear resonance fluorescence are presented. (Auth.)