High-spin states in the direct 12, 13C(α, p) 15, 16N reactions

The ^{12, 13}C(α, p) reactions at E_α = 35 MeV are used to study high-spin states in ¹⁵N and ¹⁶N. Theoretical prescriptions are given for normalizing DWBA predictions in a semi-microscopic model and for comparing differential cross sections in the two reactions. Angular distributions are presented for many states, with DWBA analyses for those of high spin, from 10.7 to 15.4 MeV in ¹⁵N and from 0 to 11.8 MeV in ¹⁶N. The observed magnitudes are larger than predicted. In ¹⁶N, a 4 ^- state is observed at 6.17 MeV, and theoretical comparisons indicate that a member of the strong triplet of states at 7.6 MeV, resolved in this study, has also a 4 ^- spin. Strong peaks are observed at 15.42 MeV in ¹⁵N and at 11.75 MeV in ¹⁶N, but neither peak can be explained by our theoretical analysis. The DWBA angular distributions depend sensitively on the choice of the α-particle optical potential.