Projected sensitivity of the LUX-ZEPLIN (LZ) experiment to the two-neutrino and neutrinoless double beta decays of $^{134}$Xe

TL;DR

The paper evaluates the LUX-ZEPLIN experiment's potential to detect double beta decay of $^{134}$Xe, highlighting its sensitivity and expected limits on decay half-lives for both two-neutrino and neutrinoless modes.

Contribution

It provides the first projected sensitivity analysis of LZ for $^{134}$Xe double beta decay, emphasizing its unique capability compared to enriched $^{136}$Xe detectors.

Findings

LZ can exclude two-neutrino decay half-lives up to 1.7×10^{24} years at 90% CL.

LZ can exclude neutrinoless decay half-lives up to 7.3×10^{24} years at 90% CL.

LZ has a three-sigma observation potential of 8.7×10^{23} years for two-neutrino decay.

Abstract

The projected sensitivity of the LUX-ZEPLIN (LZ) experiment to two-neutrino and neutrinoless double beta decay of $^{134}$Xe is presented. LZ is a 10-tonne xenon time projection chamber optimized for the detection of dark matter particles, that is expected to start operating in 2021 at Sanford Underground Research Facility, USA. Its large mass of natural xenon provides an exceptional opportunity to search for the double beta decay of $^{134}$Xe, for which xenon detectors enriched in $^{136}$Xe are less effective. For the two-neutrino decay mode, LZ is predicted to exclude values of the half-life up to 1.7$\times$10$^{24}$ years at 90% confidence level (CL), and has a three-sigma observation potential of 8.7$\times$10$^{23}$ years, approaching the predictions of nuclear models. For the neutrinoless decay mode LZ, is projected to exclude values of the half-life up to 7.3$\times$10$^{24}$ years at 90% CL.