The 42,44Ca(p, t) 40,42Ca reactions at 26.5 MeV

Abstract

The 42Ca and 44Ca(p, t) reactions at 26.5 MeV have been examined with a triton energy resolution of 110 keV. Differential cross sections were obtained for six levels in 40Ca and eleven levels in 42Ca below an excitation energy in both nuclei of approximately 5 MeV; they are compared with theoretical angular distributions calculated using the zero-range distorted wave Born approximation (DWBA) in the two-nucleon transfer formalism of Glendenning. Woods-Saxon wave functions described the bound states of each of the individual transferred neutrons. The theoretical predictions for a given transition were found to be extremely sensitive to optical-model parameters, well parameters and shell-model configurations of the wave functions of the transferred neutrons. Therefore only qualitative information could be extracted from the data. In the 42Ca(p, t) 40Ca reaction, the first excited 0 + state at 3.35 MeV was excited approximately 13% as strongly as the ground state. This is inconsistent with this state being a pure two-hole-two-particle configuration if pure shell-model ground state configurations are assumed. In the 44Ca(p, t) reaction, the first excited 0 + state in 42Ca at 1.84 MeV was excited only 2% as strongly as the ground state; this is consistent with a predominantly four-particle-two-proton-hole configuration for this state. The proton elastic differential cross sections for 42Ca were measured to aid in the selection of proton optical-model parameters.