Probing neutrinoless double beta decay with SNO+

TL;DR

This paper discusses the adaptation of the SNO+ detector for neutrinoless double beta decay searches using Te-loaded scintillator, estimating its sensitivity and exploring additional decay modes like Majoron emission.

Contribution

It presents a comprehensive background model and sensitivity estimate for SNO+'s neutrinoless double beta decay search with Te-loaded scintillator, including potential sensitivity to Majoron modes.

Findings

Expected sensitivity of 9.4×10^{25} years for half-life at 90% CL

Target loading of 0.3% natural Te with ~790 kg isotope

Potential sensitivity to Majoron-emitting decay modes

Abstract

Probing neutrinoless double beta decay is one of the primary goals for SNO+, SNOLAB's multi-purpose neutrino detector. In order to achieve this goal the SNO detector has been adapted so that it can be filled with Te-loaded liquid scintillator. During the initial double beta phase the target loading is 0.3% natural Te, which equates to $\sim790$ kg of double beta isotope. Estimating the sensitivity to neutrinoless double beta decay requires a well understood background model. For SNO+ this is provided by a comprehensive study considering all possible background contributions, whether they originate from within the liquid scintillator cocktail, the surrounding parts of the detector or other irreducible backgrounds. Given these considerations, for five years running in the initial phase, the expected sensitivity is $T_{1/2}^{0\nu\beta\beta} = 9.4\times10^{25}$ at 90% CL. In these proceedings we introduce the Majoron-emitting neutrinoless double beta decay modes, to which SNO+ may also be sensitive.