Electromagnetic dissociation of B-8 and the rate of the Be-7(p, gamma)B-8 reaction in the Sun - art. no. 065806

In an effort to better determine the Be-7(p, gamma)B-8 reaction rate, we ha ve performed inclusive and exclusive measurements of the Coulomb dissociati on of B-8. The former was a study of longitudinal momentum distributions of Be-7 fragments emitted in the Coulomb breakup of intermediate energy B-8 b eams on Pb and Ag targets. Analysis of these data yielded the E2 contributi on to the breakup cross section. In the exclusive measurement. we determine d the cross section for the Coulomb breakup of B-8 on Pb at low relative en ergies in order to infer the astrophysical S factor for the Be-7(p, gamma)B -8 reaction. Interpreting the measurements with first-order perturbation th eory, we obtained S-E2/S-E1 = 4.7(-1.3)(+2.0) x 10(-4) at E-rel = 0.6 MeV, and S-17(0) =17.8(-1.2)(+1.4) eV b. Semiclassical first-order perturbation theory and fully quantum mechanical continuum-discretized coupled channels analyses yield nearly identical results for the El strength relevant to sol ar neutrino flux calculations, suggesting that theoretical reaction mechani sm uncertainties need not limit the precision of Coulomb breakup determinat ions of the Be-7(p, gamma)B-8 S factor. A recommended value of S-17(0) base d on a weighted average of this and other measurements is presented.