Search for 2β processes in 64Zn with the help of ZnWO4 crystal scintillator

Abstract

Double beta processes in 64 Zn were searched for with the help of a low background ZnWO 4 crystal scintillator (mass of 117 g) at the Gran Sasso National Laboratories of the INFN. Total time of measurements was 1902 h. New improved half-life limits on different modes of double electron capture and electron capture with positron emission were established as: T 22K 1/2 6.2 10 18 yr, T 02K 1/2 4.0 10 18 yr, T 02 1/2 3.4 10 18 yr, T 2 + 1/2 2.1 10 20 yr, and T 0 + 1/2 2.2 10 20 yr, all at 90% C.L.