Searches for the β+/EC decays of 64Zn and 112Sn, and the ββ decay transitions of 124Sn to the excited states of 124Te

Results of searches for the β+/EC decays of 64Zn and 112Sn, and the ββ decay of 124Sn to excited states in 124Te are presented. This work was done at the ChyungPyung Underground Laboratory. An ultra-low background HPGe detector with/without CsI(Tℓ) crystal was used for gamma tagging. No evidence of any of these decay modes has been found. Lower limits on the half-lives on the 124Sn decay to different excited channels of ββ decay are set in the range of 1018–1019 years by 90% C.L. Lower limits of the half-lives of β+/EC decay of 64Zn, 112Sn are obtained to be 9.1×1017 years and 1.3×1020 years by 90% C.L., respectively.