Searching for Two-Neutrino and Neutrinoless Double Beta Decay of $^{134}$Xe with the PandaX-4T Experiment

TL;DR

This study uses the PandaX-4T detector to set new, stringent limits on the half-lives of two-neutrino and neutrinoless double beta decay of $^{134}$Xe, demonstrating the potential of large natural xenon detectors in rare decay searches.

Contribution

First constraints on $^{134}$Xe double beta decay using a large xenon detector, surpassing previous limits significantly.

Findings

Established half-life limits: $2.8×10^{22}$ yr for $2 uetaeta$ and $3.0×10^{23}$ yr for $0 uetaeta$.

Limits surpass previous results by factors of 32 and 2.7.

Highlights the potential of large natural xenon detectors for rare decay searches.

Abstract

$^{134}$Xe is a candidate isotope for neutrinoless double beta decay~($0\nu\beta\beta$) search. In addition, the two-neutrino case ($2\nu\beta\beta$) allowed by the Standard Model of particle physics has not yet been observed. Utilizing the 10.4% of $^{134}$Xe in the natural xenon in the PandaX-4T detector and its first 94.9-day exposure, we have established the most stringent constraints on $2\nu\beta\beta$ and $0\nu\beta\beta$ of $^{134}$Xe half-lives, with limits of $2.8\times10^{22}$ yr and $3.0\times10^{23}$ yr at 90% confidence level, respectively. The $2\nu\beta\beta$ ($0\nu\beta\beta$) limit surpasses the previously reported best result by a factor of 32 (2.7), highlighting the potential of large monolithic natural xenon detectors.