GT STRENGTHS STUDIED BY (HE-3,T) REACTIONS AND NUCLEAR MATRIX-ELEMENTS FOR DOUBLE-BETA DECAYS

GT matrix elements M(S)(nu) for transitions of Mo-100(0(+))-->Tc-100(1 (+)) and Cd-116(0(+))-->In-116(1(+)) were obtained by measuring (He-3, t) reactions on Mo-110 and Cd-116, respectively. The values for M(S)( nu), together with the GT matrix elements M(S')(nu) for Tc-100(1(+))-- >Ru-100(0(+)) and In-116(1(+))-->Sn-116(0(+)), are applied to estimate the nuclear matrix elements M(SS')(2 nu), for the two neutrino double beta decays (2 nu beta beta) of Mo-100 and Cd-116 through the 1(+) gr ound states in the intermediate nuclei of Tc-100 and In-116, respectiv ely. They are very close to the observed 2 nu beta beta matrix element s M(2 nu), consistent with recent experimental and theoretical analyse s.