Spectroscopic study of low-lying N16 levels

The magnitude of the N-15(n,gamma)N-16 reaction rate in asymptotic giant branch stars depends directly on the neutron spectroscopic factors of low-lying N-16 levels. A new study of the N-15(d,p)N-16 reaction is reported populating the ground and first three excited states in N-16. The measured spectroscopic factors are near unity as expected from shell model calculations, resolving a long-standing discrepancy with earlier measurements that had never been confirmed or understood. Updated N-15(n,gamma)N-16 reaction rates are presented.