Effects of core degrees of freedom in the low energy $^7$Be$(p,\gamma)^8$B reaction

Abstract

Quadrupole and octupole couplings to all bound states of $^7$Be are included in describing the capture reaction $^7$Be$(p,\gamma)^8$B. We verify, contrary to what we had initially stated, that the energy behaviour of the Astrophysical S-factor in the energy range of interest is not significantly sensitive to the core couplings in the g.s. (g.s.) of $^8$B although its overall magnitude is shifted. We find there is some sensitivity to the various deformation models when introducing the nuclear interaction for calculating the scattering states. The various deformation models predict quite different contributions to the quadrupole and magnetic moments but in order to compare with the data the quadrupole and magnetic moment of $^7$Be need to be measured.