The search for neutrinoless positron emitting electron capture (0υECβ +) of 120Te with CUORE

Abstract

CUORE (Cryogenic Underground Observatory for Rare Events) is a tonne-scale experiment located at the LNGS with the main scientific goal of searching for neutrinoless double beta decay in 130Te. The detector consists of TeO2 crystals operated as cryogenic calorimeters. The use of natural tellurium allows us to search for other isotopes rare decays. The neutrinoless positron emitting electron capture (0υECβ +) of 120Te (natural abundance 0.09(1)%) has a clear signature from the 511-keV annihilation γ rays. We present an analysis of this process based on a new algorithm to perform the simultaneous spectral fit over five selected decay scenarios. Each scenario is characterized by a set of crystals simultaneously interested by a detectable energy release. We describe the background structure modeling and tests of linearity we performed on the fit algorithm. We finally present the limit setting sensitivity and the next steps of this study, including systematics accounting.