Neutrinoless double beta decay: 2015 review

TL;DR

This review discusses the significance, mechanisms, and current experimental status of neutrinoless double beta decay ($0 uetaeta$), highlighting its connection to neutrino masses and lepton-number violation.

Contribution

It provides a comprehensive overview of $0 uetaeta$, including theoretical mechanisms, experimental progress, and implications for neutrino physics and cosmology.

Findings

Current experiments set stringent limits on $0 uetaeta$ decay rates.

Cosmological data constrains neutrino mass models.

Future experiments aim to detect or further limit $0 uetaeta$.

Abstract

The discovery of neutrino masses through the observation of oscillations boosted the importance of neutrinoless double beta decay ($0\nu\beta\beta$). In this paper, we review the main features of this process, underlining its key role both from the experimental and theoretical point of view. In particular, we contextualize the $0\nu\beta\beta$ in the panorama of lepton-number violating processes, also assessing some possible particle physics mechanisms mediating the process. Since the $0\nu\beta\beta$ existence is correlated with neutrino masses, we also review the state-of-art of the theoretical understanding of neutrino masses. In the final part, the status of current $0\nu\beta\beta$ experiments is presented and the prospects for the future hunt for $0\nu\beta\beta$ are discussed. Also, experimental data coming from cosmological surveys are considered and their impact on $0\nu\beta\beta$ expectations is examined.