7Be(p, γ)8B S-factor from ab initio wave functions

Nuclear structure of Be-7, B-8 and Li-7,Li-8 is studied within the ab initio no-core shell model (NCSM). Starting from the high-precision CD-Bonn 2000 nucleon-nucleon (NN) interaction, wave functions of Be-7 and B-8 bound states are obtained in basis spaces up to 10h Omega and used to calculate channel cluster form factors (overlap integrals) of the 8B ground state with Be-7+p. Due to the use of the harmonic oscillator (HO) basis, the overlap integrals have incorrect asymptotic properties. We fix this problem in two alternative ways. First, by a Woods-Saxon (WS) potential solution fit to the interior of the NCSM overlap integrals. Second, by a direct matching with the Whittaker function. The corrected overlap integrals are then used for the Be-7(p, gamma)B-8 S-factor calculation. We study the convergence of the S-factor with respect to the NCSM HO frequency and the model space size. Our S-factor results are in agreement with recent direct measurement data. (c) 2006 Elsevier B.V. All rights reserved.