Investigations of three-, four-, and five-particle decay channels of levels in light nuclei created using a C9 beam

Abstract

The interactions of an E/A=70-MeV C9 beam with a Be target was used to populate levels in Be, B, and C isotopes, which undergo decay into many-particle exit channels. The decay products were detected in the HiRA array and the level energies were identified from their invariant mass. Correlations between the decay products were examined to deduce the nature of the decays, specifically to what extent all the fragments were created in one prompt step or whether the disintegration proceeded in a sequential fashion through long-lived intermediate states. In the latter case, information on the spin of the level was also obtained. Of particular interest is the five-body decay of the C8 ground state, which was found to disintegrate in two steps of two-proton decay passing through the Be6g.s. intermediate state. The isobaric analog of C8 g.s. in B8 was also found to undergo two-proton decay to the isobaric analog of Be6g.s. in Li6. A 9.69-MeV state in C10 was found to undergo prompt four-body decay to the 2p + 2α exit channel. The two protons were found to have a strong enhancement in the diproton region and the relative energies of all four p-α pairs were consistent with the Li5 g.s. resonance. © 2011 American Physical Society.