Studies on the double-$\beta$ decay nucleus $^{64}Zn$ using the (d,$^{2}He$) reaction
Résumé
The (d,2He) charge-exchange reaction on the double-beta decay (beta beta) nucleus 64Zn has been studied at an incident energy of 183 MeV. The two protons in the 1S0 state (indicated as 2He) were both momentum analyzed and detected simultaneously by the BBS magnetic spectrometer and its position-sensitive detector. 2He spectra with a resolution of about 115 keV (FWHM) have been obtained allowing identification of many levels in the residual nucleus 64Cu with high precision. 64Zn is one of the rare cases undergoing a beta beta decay in beta+ direction. In the experiment presented here, Gamow-Teller (GT+) transition strengths have been extracted. Together with the GT- transition strengths from 64Ni(3He,t) data to the same intermediate nucleus 64Cu, the nuclear matrix elements of the beta beta decay of 64Zn have been evaluated. Finally, the GT± distributions are compared with shell-model calculations and a critical assessment is given of the various residual interactions presently employed for the pf shell