Leptonic CP Violation and Leptogenesis

TL;DR

This paper reviews the current understanding of neutrino mixing, CP violation, and the seesaw mechanism, highlighting how leptogenesis could explain the universe's matter-antimatter asymmetry through CP-violating phases.

Contribution

It provides a comprehensive review of neutrino phenomenology, CP violation, and leptogenesis, emphasizing the role of CP phases in baryon asymmetry generation.

Findings

CP violation in neutrino oscillations is crucial for leptogenesis.

Leptogenesis can be driven solely by Dirac and/or Majorana CP phases.

The seesaw mechanism links neutrino masses to the matter-antimatter asymmetry.

Abstract

The phenomenology of 3-neutrino mixing, the current status of our knowledge about the 3-neutrino mixing parameters, including the absolute neutrino mass scale, and of the Dirac and Majorana CP violation in the lepton sector, are reviewed. The problems of CP violation in neutrino oscillations and of determining the nature - Dirac or Majorana - of massive neutrinos, are discussed. The seesaw mechanism of neutrino mass generation and the related leptogenesis scenario of generation of the baryon asymmetry of the Universe, are considered. The results showing that the CP violation necessary for the generation of the baryon asymmetry of the Universe in leptogenesis can be due exclusively to the Dirac and/or Majorana CP-violating phase(s) in the neutrino mixing matrix $U$, are briefly reviewed.