T=0 effective interaction in 14N and 10B

Abstract

We have calculated the 1+ and 3+, T=0 states in 14N and 10B. In a neutron-proton RPA model these two nuclei are described by the same set of equations. We first show that a bare Minnesota interaction leads to too weak binding in bothnuclei. Furthermore it does not produce a 3+ ground state in 10B as it should. Including medium effects as an exchange of phonons between the neutron-proton pair cures the desagreement in 14N but still gives a 1+ ground state in 10B with the 3+ as an excited state. The same study with a Gogny effective interaction reproduces nicely the properties of both nuclei: same agreement in 14N as previously when medium effeccts were introduced but now the 3+ in 10B becomes the ground state. This success suggests that through its density dependent term the Gogny interaction takes account of the presence of a three-body force which, in a shell model calculation, has been shown to be essential to give a 3+ ground state in 10B.