Determination of S 17 from B 8 breakup by means of the method of continuum-discretized coupled channels

The astrophysical factor for {sup 7}Be(p,{gamma}){sup 8}B at zero energy, S{sub 17}(0), is determined from an analysis of {sup 208}Pb({sup 8}B, p+{sup 7}Be){sup 208}Pb at 52 MeV/nucleon by means of the method of continuum-discretized coupled channels (CDCC) taking account of all nuclear and Coulomb breakup processes. The asymptotic normalization coefficient (ANC) method is used to extract S{sub 17}(0) from the calculated breakup cross section. The main result of the present paper is S{sub 17}(0)=20.9{sub -1.9}{sup +2.0} eV b. The error consists of 8.4% experimental systematic error and the error due to the ambiguity in the s-wave p-{sup 7}Be scattering length. This value of S{sub 17}(0) differs from the one extracted with the first-order perturbation theory including Coulomb breakup by dipole transitions: 18.9{+-}1.8 eV b. It turns out that the difference is due to the inclusion of the nuclear and Coulomb-quadrupole transitions and multistep processes of all-order in the present work. The p-{sup 7}Be interaction potential used in the CDCC calculation is also used in the ANC analysis of {sup 7}Be(p,{gamma}){sup 8}B. The value of S{sub 17}(0)=21.7{sub -0.55}{sup +0.62} eV b obtained is consistent with the previous one obtained from a precise measurement of the p-capture reaction cross section extrapolated tomore » zero incident energy, S{sub 17}(0)=22.1{+-}0.6 (expt) {+-}0.6 (theo) eV b, where (theo) stands for the error in the extrapolation. Thus, the agreement between the values of S{sub 17}(0) obtained from direct {sup 7}Be(p,{gamma}){sup 8}B and indirect {sup 8}B-breakup measurements is significantly improved.« less