Two-proton capture on the 68Se nucleus with a new self-consistent cluster model

Abstract We investigate the two-proton capture reaction of the prominent rapid proton capture waiting point nucleus, 68 Se, that produces the borromean nucleus 70 Kr ( Se 68 + p + p ). We apply a recently formulated general model where the core nucleus, 68 Se, is treated in the mean-field approximation and the three-body problem of the two valence protons and the core is solved exactly. We compare using two popular Skyrme interactions, SLy4 and SkM*. We calculate E 2 electromagnetic two-proton dissociation and capture cross sections, and derive the temperature dependent capture rates. We vary the unknown 2 + resonance energy without changing any of the structures computed self-consistently for both core and valence particles. We find rates increasing quickly with temperature below 2–4 GK after which we find rates varying by about a factor of two independent of 2 + resonance energy. The capture mechanism is sequential through the f 5 / 2 proton-core resonance, but the continuum background contributes significantly.