First excited 1\2+ state in 9B.

Evidence has been found for a broad unbound state near 1 MeV excitation in 9B that is a candidate for the long-disputed A mirror of the unbound 1.68 MeV state in9Be. Reactions of6Li+6Li were studied with a 60 MeV beam incident on a 240 ug/cm2 6LiF target. The breakup fragments from the decay of the reaction products were detected in five Si-Si-Csl telescope detectors and the breakup particles were reconstructed using the technique of resonant particle spectroscopy. It is shown that contrary to a previous study, the 1/2+ is not populated in the reaction 6Li(6Li,i)9B, but that it is populated via the 6Li(66Li,rf)10 reaction. The sequential decays of 10B populated the channels 6Li(g.s.)+a, 6Li(2.186 MeV)+a, 8Be+d, and pnaa, with the latter including (9B+n or9Be+p) decay from 10B. Decays through 9B are identified and show the presence of the | state as a broad asymmetric peak around 0.8-1.0 MeV with Γ 1.5 MeV. [ABSTRACT FROM AUTHOR]