The investigation of direct mechanisms for the 10B(p,α)7Be-reaction

The experimental angular distributions of the reaction 10B(p,α)7Be at Ep ≥21.74 MeV have diffraction patterns indicating a direct mechanism. At these incident energies the excitation energy (EX) of the compound-nucleus (11C) must be greater than the threshold separation energy of α-particle by at least ∼ 20 MeV. The states, ground (3/2- ;l/2); excited states 0.429 (1/2- ;1/2) and 4.57 (7/2- ;1/2) MeV, may be studied by means of the zero-range distorted wave Born approximation (DWBA). Using the Kurath-Millener's spectroscopic-factor amplitudes for the triton transfer in the analyses give a good fit in forward direction for both angular distributions and cross-sections. The forward and backward relative experimental transition-strengths, for the g. s.- and 4.57 MeV states, agree well with the (2I+1) values, especially at lower incident energies. However, at higher incident energies, these strengths are in agreement with the light (SLPPU) and the heavy particle pickup spectroscopic factors (SHPPU), respectively. In addition, the light-particle strengths agree well with the corresponding theoretical integrated cross-sections. A good agreement is also obtained between the calculated and experimental EX's for most 7Be-states. Generally, the present results show that the reaction-dynamics is of minor importance for the states g. s. and 4.57 MeV, while the state at 0.429 MeV could not be interpreted using the present model