High resolution (3He,t) experiment on the double-β decaying nuclei 128Te and 130Te

Gamow-Teller (GT) strength distributions have been investigated in a high-resolution (3He,t) charge-exchange experiment on the double-β (ββ ) decaying nuclei 128Te and 130Te. The experiment was carried out at the Research Center for Nuclear Physics, Osaka, with a 420-MeV incident 3He beam and the Grand Raiden magnetic spectrometer. A final-state energy resolution of 35 keV was achieved. The extracted GT strength distributions at low excitation energies in the final nuclei 128I and 130I are presented and discussed in the context of the ββ decay matrix elements for the two tellurium nuclei. The additional neutron pair in 130Te seems to produce a moderate increase in the fragmentation of the low-energy GT distribution.