Coulomb breakup of 8B and the flux of 8B neutrinos from the Sun
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A kinematically complete measurement was made of the Coulomb dissociation of 8B nuclei on a Pb target at 83 MeV/nucleon. The cross-section was measured at low relative energies in order to infer the astrophysical S-factor for the 7Be(p,γ)8B reaction. A first-order perturbation theory analysis of the reaction dynamics including E1, E2, and M1 transitions was employed to extract the E1 strength relevant to neutrino-producing reactions in the solar interior. By fitting the measured cross-section from Erel = 130 keV to 400 keV, we find S17(0) = 17.8+1.4-1.2 eV b. Semiclassical 1st-order perturbation theory and fully quantum-mechanical continuum-discretized coupled-channels analyses yield nearly identical results for the E1 strength relevant to solar-neutrino flux calculations, suggesting that theoretical reaction mechanism uncertainties need not limit the precision of Coulomb-breakup determinations of the 7Be(p,γ)8B S-factor. A recommended value of S17(0) based on a weighted average of this and other measurements is presented. This recommendation implies a revised value for the theoretical flux of 8B solar neutrinos, which is also given.-1
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