Implications of $\mu -\tau$ Flavored CP Symmetry of Leptons

Abstract

We discuss gauge models incorporating $\mu -\tau$ flavored CP symmetry (called CP${}^{\mu \tau }$ in the text) in combination with $L_{\mu }-L_{\tau }$ invariance to understand neutrino mixings and discuss their phenomenological implications. We show that viable leptogenesis in this setting requires that the lightest right-handed neutrino mass must be between $10^9-10^{12}$ GeV and for effective two hierarchical right-handed neutrinos, leptogenesis takes place only in a narrower range of $5\times 10^{10}-10^{12}$ GeV. A multi-Higgs realization of this idea implies that there must be a pseudoscalar Higgs boson with mass less than 300 GeV. Generically, the vev alignment problem can be naturally avoided in our setting.

Comments: 34pp. v3: matches journal version