Astrophysical reaction rates for 10B(p,α)7Be and 11B(p,α)8Be from a direct model

The reactions 10B(p,α)7Be and 11B(p,α)8Be are studied at thermonuclear energies using DWBA calculations. For both reactions, transitions to the ground states and first excited states are investigated. In the case of 10B(p,α)7Be, a resonance at Eres=10 keV can be consistently described in the potential model, thereby allowing the extension of the astrophysical S-factor data to very low energies. Strong interference with a resonance at about Eres=550 keV require a Breit-Wigner description of that resonance and the introduction of an interference term for the reaction 10B(p,α1)7Be*. Two isospin T=1 resonances (at Eres1=149 keV and Eres2=619 keV) observed in the 11B+p reactions necessitate Breit-Wigner resonance and interference terms to fit the data of the 11B(p,α)8Be reaction. S-factors and thermonuclear reaction rates are given for each reaction. The present calculation is the first consistent parametrization for the transition to the ground states and first excited states at low energies. copyright 1996 The American Physical Society