Mechanism of the 15N(p, α)12C reaction at Ep=9.09-43.7 MeV

The spectroscopic-factor amplitudes for the triton-cluster transfer are used in distorted wave born approximation (DWBA) analyses for the first six 12C states, up to Ex=17.76 MeV, in the reaction 15N(p, α) for Ep=9.09-43.7 MeV. Agreements are obtained for most 12C states between the theoretically predicted spectroscopic factors (S) and both of experimental and theoretical forward integrated cross-section values (at Ep∼43.7 MeV) and their sequence states with the same nuclear parameters. The theoretical spectroscopic factors failed to predict the transition strengths for the two 12C states at 7.6542 and 17.76 MeV, while the DWBA predictions failed to reproduce the strengths of the three 12C states at 7.6542, 14.083 and 17.76 MeV. This is probably, in the first case, due to the inclusion of other direct mechanisms and (or) to the multi-step processes in their mechanism, while for the second case, it is may be due to either the angular momentum mismatching effect or the choice of the optical parameters. The agreement between theoretical and experimental data for the first six investigated 12C states indicate the success of the Cohen-Kurath wave-functions itself and their accuracy. They also indicate the success of the model of calculations of spectroscopic factors.