Search for Neutrinoless $\beta^{+}\hspace{-0.2em}EC$ Decay of $^{120}$Te with CUORE-0

TL;DR

This paper reports a search for neutrinoless $eta^{+}EC$ decay of $^{120}$Te using CUORE-0 data, introducing a new analysis method, and sets the most stringent half-life limit to date at over 2.7×10^{21} years.

Contribution

It presents a novel analysis technique for detecting neutrinoless $eta^{+}EC$ decay signatures and combines results with previous experiments to improve the half-life limit.

Findings

Established a new lower limit on the decay half-life of $^{120}$Te.

Developed a new analysis method for different event topologies.

Achieved the strongest limit to date by combining CUORE-0 and Cuoricino data.

Abstract

We have performed a search for neutrinoless $\beta^{+}\hspace{-0.2em}EC$ decay of $^{120}$Te using the final CUORE-0 data release. We describe a new analysis method for the simultaneous fit of signatures with different event topology, and of data subsets with different signal efficiency, obtaining a limit on the half-life of the decay of $T_{1/2}>1.6\cdot10^{21}$ yr at $90\%$ CI. Combining this with results from Cuoricino, a predecessor experiment, we obtain the strongest limit to date, corresponding to $T_{1/2}>2.7\cdot10^{21}$ yr at $90\%$ CI.