MESONIC EFFECTS DEDUCED FROM GOOD-RESOLUTION (HE-3, T) REACTION IN COMPARISON WITH INELASTIC SCATTERINGS

Gamow-Teller (GT) states excited by a charge-exchange reaction on N = Z nuclei with ground-state isospin T = 0 have isospin T = 1, while M1 states excited by inelastic scattering of electrons or protons can hav e either T = 0 or T = 1. The latter are the isobaric analog states of the GT states. By comparing the GT states observed in the good-resolut ion (He-3, t) reaction at 150 MeV/u with the M1 states observed in ine lastic proton reactions, the isospin of each 1(+) state in Si-28 was d etermined. Furthermore, by comparing results from electron inelastic s cattering induced by electro-magnetic M1 operator, different response of nucleus depending on different interaction is investigated, Based o n these comparisons among different probes, we discuss (1) the contrib ution of the ''Delta-h excitation'' mechanism in the quenching of magn etic excitations; (2) the effects of meson exchange currents; and (3) the orbital contribution in the M1 operator.