GT strengths studied by (3He, t) reactions and nuclear matrix elements for double beta decays

GT matrix elements MSν for transitions of 100Mo(0+) → 100Tc(1+) and 116Cd(0+) → 116In(1+) were obtained by measuring (3He, t) reactions on 100Mo and 116Cd, respectively. The values for MSν, together with the GT matrix elements MS′ν for 100Tc(1+) → 100Ru(0+) and 116In(1+) →116Sn(+), are applied to estimate the nuclear matrix elements MSS′2ν for the two neutrino double beta decays (2νββ) of 100Mo and 116Cd through the 1+ ground states in the intermediate nuclei of 100Tc and 116In, respectively. They are very close to the observed 2νββ matrix elements M2ν, consistent with recent experimental and theoretical analyses.