Measurement of Double Beta Decay Half-life of $^{136}$Xe with the PandaX-4T Detector

TL;DR

This paper reports the first measurement of the two-neutrino double beta decay half-life of $^{136}$Xe using the PandaX-4T detector, demonstrating the potential of large-scale liquid xenon TPCs in rare event physics.

Contribution

It provides the first DBD half-life measurement with natural xenon and showcases the physics capabilities of a large-scale liquid xenon TPC.

Findings

Measured half-life as $2.27 imes 10^{21}$ years with uncertainties.

First DBD half-life measurement using natural xenon.

Demonstrates large-scale liquid xenon TPC's potential in rare event searches.

Abstract

Precise measurement of two-neutrino double beta decay (DBD) half-life is an important step for the searches of Majorana neutrinos with neutrinoless double beta decay. We report the measurement of DBD half-life of $^{136}$Xe using the PandaX-4T dual-phase Time Projection Chamber (TPC) with 3.7-tonne natural xenon and the first 94.9-day physics data release. The background model in the fiducial volume is well constrained in situ by events in the outer active region. With a $^{136}$Xe exposure of 15.5 kg-year, we establish the half-life as $2.27 \pm 0.03 (stat.)\pm 0.10 (syst.)\times 10^{21}$ years. This is the first DBD half-life measurement with natural xenon and demonstrates the physics capability of a large-scale liquid xenon TPC in the field of rare event searches.