---
abstract: 'Assuming 3-$\nu$ mixing and massive Majorana neutrinos, we analyze the possibility of establishing the existence of CP-violation associated with Majorana neutrinos in the lepton sector by i) measuring of the effective Majorana mass in neutrinoless double beta decay with a sufficient precision and ii) by measuring of, or obtaining a stringent upper limit on, the lightest neutrino mass $m_1$. Information on $m_1$ can be obtained in the [$\mbox{}^3 {\rm H}$ $\beta$-decay ]{}experiment KATRIN and from astrophysical and cosmological observations. Proving that the indicated CP-violation takes place requires, in particular, a relative experimental error on the measured value of not bigger than 20%, a “theoretical uncertainty” in the value of due to an imprecise knowledge of the corresponding nuclear matrix elements smaller than a factor of 2, a value of $\tan^2\theta_{\odot} \gtap 0.55$, and values of the relevant Majorana CP-violating phases typically within the intervals of $\sim (\pi/2 - 3\pi/4)$ and $\sim (5\pi/4 - 3\pi/2)$.'
---

[**On the CP Violation Associated with Majorana Neutrinos\
and Neutrinoless Double-Beta Decay** ]{}

S. Pascoli $^{a,b)}$, 0.2cm S. T. Petcov $^{a,b)}$ [^1]  and  W. Rodejohann $^{c)}$

[*$^{a)}$Scuola Internazionale Superiore di Studi Avanzati, I-34014 Trieste, Italy\
*]{}

Introduction
============

1.0truecm The recent results of 