Charge-exchange spin-dipole and quasifree excitations in p-shell nuclei

Abstract

We have measured (p,n) differential cross sections and $\text{(}\text{p}\text{,}\text{n}\text{)}$ spin observables at E_p = 186 MeV on p-shell nuclei, ^6,7Li, ^10,11B and ^12,13C, using the neutron time-of-flight facilities at the Indiana University Cyclotron Facility. Cross section data were measured between θ_lab = 0° and θ_lab = 50° in 5° steps. Spin observables D_NN, A_y and P were measured at θ_lab = 15° and 20°. Data for low-lying states and giant resonances in the nuclear sector and excitation of the quasifree have been obtained. Using a multipole decomposition analysis, results for the giant spin-dipole resonances are presented and compared with distorted-wave impulse approximation calculations. Contributions of the quasifree excitation in the giant resonance region are estimated. An analysis of the quasifree cross section is presented. Results of the location of the quasifree peak as a function of momentum transfer differ from similar (p,n) results obtained at E_p = 495 MeV.