Spin decomposition of the responses of 44Ca and 48Ca to 300 MeV protons

Angular distributions of the double-differential cross section d²σ/dΩ dE(σ) and the spin-flip probability S_nn have been measured for inclusive proton inelastic scattering from ⁴⁴Ca at 290 MeV and from ⁴⁸Ca at 318 MeV. Excitation energies up to about 50 MeV for ⁴⁴Ca and 40 MeV for ⁴⁸Ca have been investigated over the laboratory angular ranges of 3° to 12° for ⁴⁴Ca and 3° to 9° for ⁴⁸Ca. Multipole decompositions of angular distributions of both the spin-flip cross section σS_nn and the estimated cross section for ΔS=0 transitions have been performed. Distributions of strengths were deduced for ΔL=1, ΔS=0 (the giant dipole), ΔL=2, ΔS=0 (the giant quadrupole), ΔL=0, ΔS=1 (the magnetic dipole), ΔL=1, ΔS=1 (the spin dipole), and ΔL=2, ΔS=1 (the spin quadrupole). The ΔS=0 summed strengths for ⁴⁴Ca are lower than for ⁴⁰Ca and ⁴⁸Ca. The spin-dipole summed strengths are found to be approximately independent of A. For ⁴⁸Ca, essentially all M1 strength observed was in the 10.23 MeV 1⁺ state; for ⁴⁴Ca, M1 strength was observed to be fragmented over a range of 7 to 18 Mev.