Majorana CP Violation in Approximately μ-τSymmetric Models with det(M_ν)=0

Abstract

We discuss effects of Majorana CP violation in a model-independent way for a given phase structure of flavor neutrino masses. To be more predictive, we confine ourselves to models with $\det (M_{\nu })=0$, where $M_{\nu }$ is a flavor neutrino mass matrix, and to be consistent with observed results of the neutrino oscillation, the models are subject to an approximate $\mu$-$\tau$ symmetry. There are two categories of approximately $\mu$-$\tau$ symmetric models classified as (C1) yielding ${\sin }^{2}2{\theta }_{23}\approx 1$ and ${\sin }^2{\theta }_{13}\ll 1$ and (C2) yielding ${\sin }^{2}2{\theta }_{23}\approx 1$ and $\Delta m_{\odot }^2/|\Delta m_{atm}^2|\ll 1$, where ${\theta }_{23(13)}$ stands for the mixing of massive neutrinos ${\nu }_2$ and ${\nu }_3$ (${\nu }_1$ and ${\nu }_3$) and $\Delta m_{\odot }^2$ ($\Delta m_{atm}^2$) stands for the mass squared difference for atmospheric (solar) neutrinos. The Majorana phase can be large for the normal mass hierarchy and for the inverted mass hierarchy with $m_1\approx -m_2$ only realized in (C1) while they are generically small for the inverted mass hierarchy with $m_1\approx m_2$ in both (C1) and (C2). These results do not depend on a specific choice of phases in $M_{\nu }$ but hold true in any models with $\det (M_{\nu })=0$ because of the rephasing invariance.

28 pages, 7 Figures, typos in equations and references corrected, version to appear in Prog. Theor. Phys. 123, No. 4 (2010, April)

References in corpus (1)

• Mass Matrix of Majorana Neutrinos

Cited by in corpus (13)

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• Radiative neutrino masses, lepton flavor mixing and muon $g-2$ in a leptoquark model
• The $\mu -\tau$ reflection symmetry of Dirac neutrinos and its breaking effect via quantum corrections
• Maximal CP Violation in Flavor Neutrino Masses
• Correlation of normal neutrino mass ordering with upper octant of ${\theta }_{23}^{}$ and third quadrant of $\delta$ via RGE-induced $\mu$-$\tau$ symmetry breaking
• Charged lepton contributions to bipair neutrino mixing
• The Kobayashi-Maskawa Parametrization of Lepton Flavor Mixing and Its Application to Neutrino Oscillations in Matter
• Bi-pair Neutrino Mixing
• Flavor Neutrino Masses giving sinθ_{13}=0
• CP violation in bipair neutrino mixing
• Phases of Flavor Neutrino Masses and CP Violation