UNCERTAINTIES IN THE GROUND-STATE STRUCTURE OF B-8 AND IMPLICATIONS FOR THE S-17 ASTROPHYSICAL S-FACTOR

In calculating the Be-7(p,gamma) B-8 reaction rate, various single par ticle models have been used to describe the g.s. of B-8. We show that these models produce electric excitation strength distributions that c an differ greatly (similar or equal to 30%) from the pioneering model, providing the community with a wide range of values for the low energ y S-factor, even if no other differences in the reaction theory are in troduced. When allowing for deformation of the Be-7 core, the maximum of the dB(E1)/dE distribution can be reduced by (similar or equal to 1 5%) and the peak shifts slightly to higher energies. The change in the B(E1) distribution modifies the low energy behaviour of the astrophys ical S-factor and brings a reduction of its overall magnitude. (C) 199 7 Elsevier Science B.V.