Direct experimental evidence for strong admixture of different parity states in Li-11

Abstract

Peripheral fragmentation of a 287 MeV/nucleon beam of the halo nucleus Li-11 incident on a carbon target has been studied in a fragment-neutron coincidence experiment. The momentum distribution of the Li-10 fragments gives access to the momentum distribution of the removed neutron in Li-11. From the shape of the distribution, the (1s(1/2))(2) contribution to the mixture of (1s(1/2))(2) and (0p(1/2))(2) components in the ground-state wave function was determined to he (45 ± 10)%. The angular correlation between the knocked out neutron and the one from the decay of Li-10 shows a skew distribution signaling interference of these two different parity states.