Author/Authors :
Fujita، نويسنده , , Y. and Akimune، نويسنده , , H. and Daito، نويسنده , , I. and Fujiwara، نويسنده , , M. N. Harakeh، نويسنده , , M.N. and Inomata، نويسنده , , T. and Jنnecke، نويسنده , , J. and Katori، نويسنده , , K. and Lüttge، نويسنده , , Itsuki C. and Nakayama، نويسنده , , S. and von Neumann-Cosel، نويسنده , , Marc P. and Richter، نويسنده , , A. and Tamii، نويسنده , , A. and Tanaka، نويسنده , , M. and Ueno، نويسنده , , H. and Yosoi، نويسنده , , M.، نويسنده ,
Abstract :
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 have 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-resolution (3He, t) reaction at 150 MeV/u with the M1 states observed in inelastic proton reactions, the isospin of each 1+ state in 28Si was determined. Furthermore, by comparing results from electron inelastic scattering induced by electro-magnetic M1 operator, different response of nucleus depending on different interaction is investigated. Based on these comparisons among different probes, we discuss (1) the contribution of the “Δ-h excitation” mechanism in the quenching of magnetic excitations; (2) the effects of meson exchange currents; and (3) the orbital contribution in the M1 operator.
Keywords :
Orbital current , Good-resolution (3He , t) reaction , Isospin structure , Meson exchange current , Quenching of Gamow-Teller strengths
