A background free double beta decay experiment

TL;DR

This paper proposes a novel background rejection method for neutrinoless double beta decay experiments using Cherenkov light detection, enhancing the ability to distinguish signal from background in various detector configurations.

Contribution

It introduces a new detection scheme based on Cherenkov light for background discrimination, adaptable to multiple detector types and target materials, including high-pressure xenon TPCs and spherical proportional counters.

Findings

Cherenkov light detection improves background rejection.

High-pressure 136Xe TPCs can be optimized with adjustable energy thresholds.

Spherical Proportional Counters offer a simple, low-cost solution for background discrimination.

Abstract

We present a new detection scheme for rejecting backgrounds in neutrino less double beta decay experiments. It relies on the detection of Cherenkov light emitted by electrons in the MeV region. The momentum threshold is tuned to reach a good discrimination between background and good events. We consider many detector concepts and a range of target materials. The most promising is a high-pressure 136Xe emitter for which the required energy threshold is easily adjusted. Combination of this concept and a high pressure Time Projection Chamber could provide an optimal solution. A simple and low cost effective solution is to use the Spherical Proportional Counter that provides two delayed signals from ionization and Cherenkov light. In solid-state double beta decay emitters, because of their higher density, the considered process is out of energy range. An alternative solution could be the development of double decay emitters with lower density by using for instance the aerogel technique. It is surprising that a technology used for particle identification in high-energy physics becomes a powerful tool for rejecting backgrounds in such low-energy experiments.