Identification of the Li-10 ground state

The proton-stripping reaction from a Be-11 radioactive beam incident on a b eryllium target demonstrates that only (7 +/- 3)% of the Li-9 residues in t he reaction are in coincidence with the 2.7 MeV gamma -ray corresponding to the Li-9 first excited state. This implies that the previously observed lo w-energy neutrons from the decay of the unbound nucleus Li-10 represent a d irect l = 0 transition to the Li-9 ground state. Consequently, neutron-unbo und Li-10 is proven to have the same parity inversion as occurs in the case of tin, with a 1s(1/2) intruder state below the natural parity 0p(1/2) sta te. Q 2001 Published by Elsevier Science B.V.