The seesaw path to leptonic CP violation

TL;DR

Future high-intensity experiments could detect heavy Majorana neutrinos and potentially discover leptonic CP violation within seesaw models, significantly advancing our understanding of neutrino physics.

Contribution

This paper demonstrates that upcoming experiments can measure neutrino mixing to electrons and muons, enabling potential discovery of leptonic CP violation in seesaw models.

Findings

A 5σ discovery of leptonic CP violation is possible in a significant part of parameter space.

Future experiments like SHiP and high-energy colliders have high sensitivity to heavy Majorana neutrinos.

The minimal seesaw model allows for quantifiable CP discovery potential in upcoming experiments.

Abstract

Future experiments such as SHiP and high-intensity $e^+ e^-$ colliders will have a superb sensitivity to heavy Majorana neutrinos with masses below $M_Z$. We show that the measurement of the mixing to electrons and muons of one such state could imply the discovery of leptonic CP violation in the context of seesaw models. We quantify in the minimal model the CP discovery potential of these future experiments, and demonstrate that a 5$\sigma$ CL discovery of leptonic CP violation would be possible in a very significant fraction of parameter space.