Double electron capture searches in ${}^{74}$Se

Abstract

A search for various double electron capture modes of ${}^{74}$Se has been performed using an ultralow background Ge-detector in the Felsenkeller laboratory, Germany. Especially for the potentially resonant transition into the 1204.2 keV excited state of ${}^{74}$Ge a lower half-life limit of $0.70\cdot 10^{19}$ yr (90% credibility) has been obtained. Serious concerns are raised about the validity of obtained ${}^{74}$Se limits in some recent publications.