CP Violation in Predictive Neutrino Mass Structures

Abstract

We study the CP violation effects from two types of neutrino mass matrices with (i) $(M_ν)_{ee}=0$, and (ii) $(M_ν)_{ee}=(M_ν)_{eμ}=0$, which can be realized by the high dimensional lepton number violating operators $\bar \ell_R^cγ^μL_L (D_μΦ)Φ^2$ and $\bar \ell_R^c l_R (D_μΦ)^2Φ^2$, respectively. In (i), the neutrino mass spectrum is in the normal ordering with the lightest neutrino mass within the range $0.002\,{\rm eV}\lesssim m_0\lesssim 0.007\,{\rm eV}$. Furthermore, for a given value of $m_0$, there are two solutions for the two Majorana phases $α_{21}$ and $α_{31}$, whereas the Dirac phase $δ$ is arbitrary. For (ii), the parameters of $m_0$, $δ$, $α_{21}$, and $α_{31}$ can be completely determined. We calculate the CP violating asymmetries in neutrino-antineutrino oscillations for both mass textures of (i) and (ii), which are closely related to the CP violating Majorana phases.