Double beta decay: present status

TL;DR

This paper reviews the current experimental status of double beta decay research, summarizes key results, and discusses future experiments aiming for higher sensitivity to neutrino mass.

Contribution

It provides a comprehensive overview of recent experimental results and sets benchmarks for future double beta decay investigations.

Findings

Half-life values for two-neutrino double beta decay are summarized.

Upper limits on Majorana neutrino mass are established.

Future experiments aim for sensitivity down to 0.01-0.1 eV for neutrino mass.

Abstract

The present status of double beta decay experiments (including the search for $2\beta^{+}$, EC$\beta^{+}$ and ECEC processes) are reviewed. The results of the most sensitive experiments are discussed. Average and recommended half-life values for two-neutrino double beta decay are presented. Conservative upper limits on effective Majorana neutrino mass and the coupling constant of the Majoron to the neutrino are established as $<m_{\nu} > < 0.75$ eV and $<g_{ee} > < 1.9 \cdot 10^{-4}$, respectively. Proposals for future double beta decay experiments with a sensitivity for the $<m_{\nu}>$ at the level of (0.01-0.1) eV are considered.