The 40Ca(p, t) 38Ca reaction and configuration mixing

Abstract

The 40Ca(p, t) 38Ca reaction has been investigated at 51.9 MeV and angular distributions have been obtained for transitions leading to ten states in 38Ca. Several spin-parity assignments were made. The experimental angular distributions for the J π = 2 + states at 2.20 and 3.69 MeV were reproduced by distorted wave Born approximation (DWBA) calculations assuming simple configurations consistent with the analysis of the L = 0 transitions to the ground state and the 3.06 MeV state done previously. However, the normalization factor for the 3.69 MeV state was different from that for the other states. For the L = 0 transitions to the 3.06 MeV 0 + state a different choice of the radius parameter for the bound state potential was found to require a slightly different amplitude for the 4p-4h component in 40Ca(g.s.). The angular distribution for the 3.06 MeV state was analyzed by coupled channel Born approximation (CCBA) calculations. It is shown that two-step processes via the 2 + states of 40Ca(3.90 MeV) and 38Ca(2.20 MeV) make relatively large contributions to the transition. However, a satisfactory explanation could not be obtained by the channel coupling effects alone. It appears that the observed L = 2 angular distributions which rise at far forward angles can be explained by DWBA with configuration mixing. The role of configuration mixing in (p, t) reactions is investigated using the L = 0 transitions, and it is found that the configuration mixing causes effects similar to those obtained from a change in the radius of the bound state potentials.