Spectroscopic studies of 37,39K using the 40,42Ca(p, α) reactions

Abstract

The 40Ca(p, α) 37K reaction has been studied at 42.5 MeV bombarding energy with an overall energy resolution of 45 keV. Excitation in 37K was observed for the 0.00 MeV, 3 2 +; 1.37 MeV, 1 2 +; 2.28 MeV; 2.75 MeV, 5 2 +; 3.25, 4.69, 5.69, 6.05, 7.00, 7.32 and 7.84 MeV states. No known negative parity states are populated in 37K via the (p, α) reaction, closely resembling the features observed in the 39K(p, t) 37K reaction. Results of this reaction and the previously investigated 42Ca(p, α) 39K reaction are used in a combined analysis, with emphasis on a comparison of the relative strengths of states populated in these two reactions. Core excitation, which is known to be important in the Ca nuclei, plays an important part in understanding the strengths of the observed transitions. Microscopic three-nucleon form factors were calculated for all transitions of interest, and the normalizations of these form factors used in extracting the relative strengths from zero range DWBA calculations. Simple configurations for the transferred nucleons are assumed in this comparison, in an attempt to explain the main features of the (p, α) reaction.