Structure of the /sup 6/Li. -->. p+(n. cap alpha. ) vertex: Three-body formalism

Three-body models of /sup 6/Li are used to investigate the structure of the /sup 6/Li..-->..p+(n..cap alpha..) vertex amplitude. Within the three-body framework, the formalism of the /sup 6/Li..-->..p+(n..cap alpha..) overlap amplitude is delineated. From this overlap, the formula for the central physical quantity, namely, the /sup 6/Li..-->..p+(n..cap alpha..) joint momentum distribution, is derived. It is shown that the /sup 6/Li..-->..p+(n..cap alpha..) joint momentum distribution satisfies a sum rule consistent with its probability interpretation. The sum rule is used as a check on the numerical calculation of the joint momentum distribution and to isolate terms that contribute insignificantly. By integration of the /sup 6/Li..-->..p+(n..cap alpha..) joint momentum distribution over a given range of the n..cap alpha.. excitation energy, the momentum distribution of the valence proton in /sup 6/Li is obtained. From both the /sup 6/Li..-->..p+(n..cap alpha..) joint momentum distribution and the p-(n..cap alpha..) momentum distribution, the dynamical structure of the /sup 6/Li..-->..p+(n..cap alpha..) vertex according to three-body models is uncovered.