States in 12B and primordial nucleosynthesis : (I). Spectroscopic measurements

Abstract

The 9Be(α, p) 12B and 11B(d, p) 12B reactions have been used to determine excitation energies, total widths and spin-parities for states which could correspond to astrophysically significant resonances in the 8Li(α, n) 11B reaction. Six such states are observed at E x = 10.199, 10.417, 10.564, 10.880, 11.328 and 11.571 MeV. None of these states corresponds to the broad resonance observed in the 11B(n, α) 8Li reaction. However, we find no evidence that such a resonance exists.