Electron capture decay of 116In and nuclear structure of double β decays

Quasiparticle-random-phase-approximation (QRPA) calculations of double beta decays have not been able to reproduce data in the A = 100 system. We propose the A = 116 system-because of its smaller deformation-as a simpler system to test QRPA calculations. We present results of two experiments we performed, which determine the electron-capture-decay branch of In-116 to be (2.27+/-0.63)x 10(-2)%, from which we deduce logft=4.39(-0.15)(+0.10). We present QRPA calculations and compare their predictions to experimental data. Finally we use these calculations to predict the 2 nu double-beta-decay rate of Cd-116 to the ground and excited states of Sn-116.