Effect of the continuum on pairing enhancement in a two-neutron transfer process

Abstract

Enhancement, due to constructive interference through the many possible reaction channels, occurs in two-neutron transfer reactions from a bound system A to a weakly-bound system (A+2), whenever the intermediate system is unbound and consists of a continuum with a resonant state. We elucidate this phenomenon in the case of 6He, modeled as two neutrons in the orbitals of an intermediate 5He nucleus, comparing the realistic case of an unbound (A+1) system with an artificially bound case. A properly modeled continuum in these calculations is found to be crucial and leads to significant enhancement due to pairing correlations.