Spin decomposition of the responses ofCa44andCa

Abstract

Angular distributions of the double-difFerential cross section d o /dQ dE {o ) and the spin-flip probability S""have been measured for inclusive proton inelastic scattering from Ca at 290 MeV and from 'Ca at 318 MeV. Excitation energies up to about 50 MeV for~Ca and 40 MeV for 'Ca have been investigated over the laboratory angular ranges of 3' to 12' for Ca and 3' to 9 for Ca. Multipole decompositions of angular distributions of both the spin-Rip cross section o. S""and the estimated cross section for AS =0 transitions have been performed. Distributions of strengths were deduced for hL = 1, hS =0 {the giant dipole), AL =2, AS =0 (the giant quadrupole), AL =0, AS = 1 {the magnetic dipole), hL = 1, AS =1 {the spin dipole), and AL =2, ES =1 {the spin quadrupole). The ES =0 summed strengths for Ca are lower than for " Ca and 'Ca. The spin-dipole summed strengths are found to be approximately independent of A. For Ca, essentially all M1 strength observed was in the 10.23 MeV 1+ state; for Ca, M1 strength was observed to be fragmented over a range of 7 to 18 Mev.