Neutrinoless Double-Beta Decay: a Probe of Physics Beyond the Standard Model

TL;DR

This review discusses neutrinoless double-beta decay as a key probe for physics beyond the Standard Model, focusing on Majorana neutrino masses, theoretical frameworks, nuclear matrix element calculations, and experimental status.

Contribution

It provides a comprehensive overview of the theory, phenomenology, and current experimental efforts related to neutrinoless double-beta decay and Majorana neutrinos.

Findings

Neutrinoless double-beta decay indicates lepton number violation.

Current experimental limits constrain Majorana neutrino masses.

Theoretical challenges remain in calculating nuclear matrix elements.

Abstract

In the Standard Model the total lepton number is conserved. Thus, neutrinoless double-beta decay, in which the total lepton number is violated by two units, is a probe of physics beyond the Standard Model. In this review we consider the basic mechanism of neutrinoless double-beta decay induced by light Majorana neutrino masses. After a brief summary of the present status of our knowledge of neutrino masses and mixing and an introduction to the seesaw mechanism for the generation of light Majorana neutrino masses, in this review we discuss the theory and phenomenology of neutrinoless double-beta decay. We present the basic elements of the theory of neutrinoless double-beta decay, our view of the present status of the challenging problem of the calculation of the nuclear matrix element of the process and a summary of the experimental results.