Neutrinos: Majorana or Dirac?

TL;DR

This paper reviews the fundamental question of whether neutrinos are Majorana or Dirac particles, discussing theoretical arguments, the phenomenology of neutrinoless double beta decay, and recent experimental insights.

Contribution

It provides a comprehensive review of the arguments for Majorana neutrinos, including phenomenological theory and recent experimental data, highlighting the importance for neutrino mass origin.

Findings

Majorana neutrinos are favored by theoretical arguments.

Recent experiments set new limits on neutrinoless double beta decay.

Future experiments may determine neutrino nature.

Abstract

Are neutrinos with definite masses Majorana or Dirac particles? This is one of the most fundamental problem of the modern neutrino physics. The solution of this problem could be crucial for understanding of the origin of small neutrino masses. We will review here basic arguments in favor of the Majorana nature of massive neutrinos. The phenomenological theory of $0\nu\beta\beta$-decay is briefly discussed and recent experimental data and sensitivity of future experiments are presented.