Double beta decay searches of Xe-134, Xe-126 and Xe-124 with large scale Xe detectors

TL;DR

This paper evaluates the potential of large-scale xenon detectors, originally designed for dark matter, to search for rare double beta decay processes in Xe-134, Xe-124, and Xe-126, considering various backgrounds and decay modes.

Contribution

It investigates the feasibility of detecting double beta decay of Xe-134, Xe-124, and Xe-126 in large xenon detectors, highlighting potential observation scenarios and background considerations.

Findings

Positive detection possible for Xe-134 double beta decay.

Xe-124 2ν ECEC detection feasible across scenarios.

Beta+/EC decay of Xe-124 may be observed, beta+/beta+ remains unobservable.

Abstract

The sensitivity for double beta decay studies of Xe-134 and Xe-124 is investigated assuming a potential large scale Xe experiment developed for dark matter searches depleted in Xe-136. The opportunity for an observation of the 2nu double beta decay of Xe-134 is explored for various scenarios. A positive observation should be possible for all calculated nuclear matrix elements. The detection of 2$\nu$ ECEC of Xe-124 can be probed in all scenarios covering the theoretical predicted half-life uncertainties and a potential search for Xe-126 is discussed. The sensitivity to beta+/EC decay of Xe-124 is discussed and a positive observation might be possible, while beta+/beta+ decay still remains unobservable. The performed studies take into account solar pp-neutrino interactions, $^{85}$Kr beta decay and remaining Xe-136 double beta decay as background components in the depleted detector.