Low-lying GT(+) strength in In-116 from a (d,He-2) reaction experiment and its implications for Cd-116 double beta decay

We have used the (d,He-2) reaction to obtain the GT(+) strength distribution for Sn-116 ->In-116 transitions. Here, In-116 is the intermediate nucleus in the second-order perturbative description of Cd-116 double beta (beta beta) decay. In this paper we will review what is known about the nuclear matrix elements for the Cd-116 2 nu beta beta decay, discuss the single-state dominance hypothesis and combine our new data with other existing data from charge-exchange reactions to obtain a 2 nu beta beta-decay half-life. The deduced value T-1/2=(4 +/- 1)x10(19)y compares well with the one known from direct counting experiments.