Pair correlations in nuclei involved in neutrinoless double β decay: Ge76 and Se76

Precision measurements were carried out to test the similarities between the ground states of {sup 76}Ge and {sup 76}Se. The extent to which these two nuclei can be characterized as consisting of correlated pairs of neutrons in a BCS-like ground state was studied. The pair removal (p,t) reaction was measured at the far forward angle of 3 deg. The relative cross sections are consistent (at the 5% level) with the description of these nuclei in terms of a correlated pairing state outside the N=28 closed shells with no pairing vibrations. Data were also obtained for {sup 74}Ge and {sup 78}Se.