Search for beta+EC and ECEC processes in Sn-112

A. S. Barabash (1) , Ph. Hubert (2) , A. Nachab (2) , S. I. Konovalov (1) , V. Umatov (1)

1 ITEP - Institute of Theoretical and Experimental Physics [Moscow]
2 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan

Limits on beta(+) EC (here EC denotes electron capture) and ECEC processes in Sn-112 have been obtained using a 380 cm(3) HPGe detector and an external source consisting of 53.355 g enriched tin (94.32% of Sn-112). A limit with 90% C.L. on the Sn-112 half-life of 4.7 x 10(20) y for the ECEC(0 nu) transition to the 0(3)(+) excited state in Cd-112 (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(0 nu) process is nearly degenerate with an excited state in the daughter nuclide. Prospects for investigating such a process in future experiments are discussed. The limits on other beta(+) EC and ECEC processes in Sn-112 were obtained on the level of (0.6-8.7) x 10(20) y at the 90% C.L.

Mots clés: NEUTRINO MASS-SPECTRUM; DOUBLE K-CAPTURE; EXCITED-STATES; DECAY; POSITRON; ELECTRON; PHYSICS

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

A. S. Barabash, Ph. Hubert, A. Nachab, S. I. Konovalov, V. Umatov. Search for beta+EC and ECEC processes in Sn-112. Physical Review C, 2009, 80, pp.035501. ⟨10.1103/PhysRevC.80.035501⟩. ⟨in2p3-00429052⟩