Search for $β^+$EC and ECEC processes in $^{112}$Sn and $β^-β^-$ decay of $^{124}$Sn to the excited states of $^{124}$Te
arXiv:0804.3849 · doi:10.1016/j.nuclphysa.2008.04.009
Abstract
Limits on $β^+$EC and ECEC processes in $^{112}$Sn and on $β^-β^-$ decay of $^{124}$Sn to the excited states of $^{124}$Te have been obtained using a 380 cm$^3$ HPGe detector and an external source consisting of natural tin. A limit with 90% C.L. on the $^{112}$Sn half-life of $0.92\times 10^{20}$ y for the ECEC(0$ν$) transition to the $0^+_3$ excited state in $^{112}$Cd (1871.0 keV) has been established. This transition is discussed in the context of a possible enhancement of the decay rate by several orders of magnitude given that the ECEC$(0ν)$ process is nearly degenerate with an excited state in the daughter nuclide. Prospects for investigating such a process in future experiments are discussed. The $β^-β^-$ decay limits for $^{124}$Sn to the excited states of $^{124}$Te were obtained on the level of $(0.8-1.2)\times 10^{21}$ y at the 90% C.L.
17 pages, 5 figures