Realistic Calculation of the hep Astrophysical Factor

The astrophysical factor for the proton weak capture on 3 He is calculated with correlated-hyperspherical-harmonics bound and continuum wave functions corresponding to a realistic Hamiltonian consisting of the Argonne v 18 two-nucleon and Urbana-IX three-nucleon interactions. The nuclear weak charge and current operators have vector and axial-vector components, that include one-and many-body terms. All possible multipole transitions connecting any of the p 3 He Sand P-wave channels to the 4 He bound state are considered. The S-factor at a p 3 He center-of-mass energy of 10 keV, close to the Gamow-peak energy, is predicted to be 10.1 × 10 −20 keV b, a factor of five larger than the standard-solar-model value. The P-wave transitions are found to be important, contributing about 40 % of the calculated S-factor.