Aspects of two-nucleon transfer reactions

Abstract

Two-nucleon transfer reactions are studied with special emphasis on the form factors. Zero-range approximation is assumed. Form factors are calculated for the reaction, 40Ca(t, p) 42Ca ground state. The nucleus 42Ca is taken to consist of two neutrons plus the 40Ca closed shell. Wave functions are determined from multiconfiguration shell-model calculations. Harmonic oscillator single-particle functions are used as a basis and the core-particle interaction is taken to be a Woods-Saxon potential. Results are presented for calculations including as many as 50 configurations. These results are generally in agreement with the calculations of Ibarra and Bayman, except that no evidence is found for the “extra node” in the radial form factor just beyond the nuclear surface. The asymptotic properties of two-nucleon form factors are discussed, and a critique is given of previous approaches, including the recent work of Ibarra. Zero-range DWBA is reformulated in such a way that the effect on the cross section of the assumed form of the interparticle potential can be studied. This also results in a cross section free of arbitrary normalization constants. The cross-section shapes were found to be insensitive to the form of the interaction and the absolute cross section predicted was found to be much too small by a factor of 15.