Beyond mean field approach to the beta decay of medium mass nuclei relevant for nuclear astrophysics

The Gamow–Teller strength distributions for the ββ decay of the ground state as well as the lowest excited states of the rp-process waiting point nuclei 68Se and 72Kr are obtained within the complex Excited Vampir variational approach using realistic effective interactions and a rather large model space. The shape mixing is consistently described for both the states in the even–even parent and the states in the odd–odd daugther nucleus. The influence of the shape mixing accounted by the different effective interactions used and comparison with the available data are presented. The possible influence of the decay of the lowest excited states of the parent nuclei in the astrophysical environment of X-ray bursts is discussed.Gamow–Teller strength distributions, ββ-decay half-lives, and ββ-delayed neutron emission probabilities for neutron-rich Zr nuclei are investigated for the first time within the complex   Excited Vampir approach using a large model space. Comparison with available data and predictions relevant for the astrophysical rr process are presented.