Off-shell effects in the (α, 2α) reaction

Abstract

The half-off-shell factor relevant to the factorized impulse-approximation treatment of the (α, 2α) reaction from 60 to 140 MeV are calculated for four phenomenological phase-shift equivalent potentials. It is found that the behaviour of the, off-shell factor is similar for all the four potentials. The off-shell effect itself is large below 140 MeV. In comparing the half-shell prescription with the various on-shell prescriptions it is found that the “final energy prescription” is consistently closer to the half-shell values.