Topological signature in the NEXT high pressure xenon TPC

TL;DR

This paper demonstrates that the topology of events in a high-pressure xenon gas TPC can significantly improve background rejection in the search for neutrinoless double beta decay, with promising results from prototypes and projections for future performance.

Contribution

It introduces a topological signature method in the NEXT experiment's xenon TPC to enhance background rejection while maintaining high signal efficiency.

Findings

Background rejection factor of 24.3% achieved with prototypes.

Signal efficiency maintained at around 66.7%.

Projected background rejection of 12.9% with 66.9% signal efficiency in the next experiment stage.

Abstract

The NEXT experiment aims to observe the neutrinoless double beta decay of Xe-136 in a high-pressure xenon gas TPC using electroluminescence to amplify the signal from ionization. One of the main advantages of this technology is the possibility to use the topology of events with energies close to Qbb as an extra tool to reject background. In these proceedings we show with data from prototypes that an extra background rejection factor of 24.3 +- 1.4 (stat.)% can be achieved, while maintaining an efficiency of 66.7 +- 1.% for signal events. The performance expected in NEW, the next stage of the experiment, is to improve to 12.9% +- 0.6% background acceptance for 66.9% +- 0.6% signal efficiency.