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

TL;DR

This paper explores gauge models with $$ flavored CP symmetry and $L_$ invariance, analyzing their impact on neutrino mixing, leptogenesis, and Higgs phenomenology, with specific predictions on right-handed neutrino masses and Higgs boson properties.

Contribution

It introduces a novel gauge model combining $$ flavored CP symmetry with $L_$ invariance, providing insights into neutrino mixing and leptogenesis.

Findings

Leptogenesis requires right-handed neutrino masses between 10^9 and 10^12 GeV.

Effective leptogenesis with two hierarchical neutrinos occurs in a narrower mass range.

A multi-Higgs model predicts a pseudoscalar Higgs below 300 GeV.

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.