What is matter according to particle physics and why try to observe its creation in lab

TL;DR

This paper explores the nature of matter in particle physics, emphasizing the importance of neutrinoless double beta decay as a key process to understand neutrino mass and the limitations of the standard model.

Contribution

It discusses the significance of Majorana's ideas on neutrino mass and highlights the potential of neutrinoless double beta decay experiments to reveal new physics beyond the standard model.

Findings

Lepton number violation observed in neutrino oscillations

Majorana's representation of gamma matrices offers useful insights

Neutrinoless double beta decay could confirm neutrinos are Majorana particles

Abstract

The standard model of elementary interactions has long qualified as a theory of matter, in which the postulated conservation laws (one baryonic and three leptonic) acquire theoretical meaning. However, recent observations of lepton number violations -- neutrino oscillations -- demonstrate its incompleteness. We discuss why these considerations suggest the correctness of Ettore Majorana's ideas on the nature of neutrino mass, and add further interest to the search for an ultra-rare nuclear process in which two particles of matter (electrons) are created, commonly called neutrinoless double beta decay. The approach of the discussion is mainly historical and its character is introductory. Some technical considerations, which highlight the usefulness of Majorana's representation of gamma matrices, are presented in the appendix.