#### Abstract

In an effort to better determine the ${}^{7}\mathrm{Be}(p,\gamma {)}^{8}\mathrm{B}$ reaction rate, we have performed inclusive and exclusive measurements of the Coulomb dissociation of ${}^{8}\mathrm{B}.$ The former was a study of longitudinal momentum distributions of ${}^{7}\mathrm{Be}$ fragments emitted in the Coulomb breakup of intermediate energy ${}^{8}\mathrm{B}$ beams on Pb and Ag targets. Analysis of these data yielded the $E2\mathrm{}$ contribution to the breakup cross section. In the exclusive measurement, we determined the cross section for the Coulomb breakup of ${}^{8}\mathrm{B}$ on Pb at low relative energies in order to infer the astrophysical *S* factor for the ${}^{7}\mathrm{Be}(p,\gamma {)}^{8}\mathrm{B}$ reaction. Interpreting the measurements with first-order perturbation theory, we obtained ${S}_{E2\mathrm{}}{/S}_{E1\mathrm{}}{=4.7\mathrm{}}_{-1.3}^{+2.0\mathrm{}}\times {10}^{-4}$ at ${E}_{\mathrm{rel}}=0.6\mathrm{}\hspace{0.5em}\mathrm{MeV},$ and ${S}_{17}{\mathrm{}\left(0\right)=17.8\mathrm{}}_{-1.2}^{+1.4\mathrm{}}\hspace{0.5em}\mathrm{eV}\mathrm{}\mathrm{b}.$ Semiclassical first-order perturbation theory and fully quantum mechanical continuum-discretized coupled channels analyses yield nearly identical results for the $E1\mathrm{}$ strength relevant to solar neutrino flux calculations, suggesting that theoretical reaction mechanism uncertainties need not limit the precision of Coulomb breakup determinations of the ${}^{7}\mathrm{Be}(p,\gamma {)}^{8}\mathrm{B}$ *S* factor. A recommended value of ${S}_{17}\mathrm{}\left(0\right)\mathrm{}$ based on a weighted average of this and other measurements is presented.

DOI: http://dx.doi.org/10.1103/PhysRevC.63.065806

- Received 14 November 2000
- Published 16 May 2001

© 2001 The American Physical Society