Flavored leptogenesis and Dirac CP violation

Abstract

In this work, we pay special attention to establish the crucial role of the Casas-Ibarra parameterization in the presence of two different orthogonal matrices, R = O eiA and R = O e A in order to investigate the role of Dirac CP violation in flavored leptogenesis. By considering these two choices of the R matrix we examine the connection between the low-energy and high-energy CP violations together with certain interesting predictions on the low-energy parameters, namely, the lightest neutrino mass and the Dirac CP phase (δ). By considering the right-handed neutrino (RHN) mass window to be 108 GeV, we show that Dirac-phase leptogenesis is possible with the choices of these two orthogonal matrices. The above forms of R matrices allow us to choose a nearly degenerate spectrum for the RHN masses. The complex R matrix predicts a maximal Dirac CP violation (δ = π/2) for leptogenesis, which can be verified by the ongoing and upcoming searches for a precise δ measurement at the neutrino factories. We also discuss the phenomenological implications of these two case studies within the context of lepton flavor violation (LFV) by considering the μ → e γ decay process, in terms of an indirect probe of the R matrix parameter space. We report an upper bound on the lightest neutrino mass (m 1) of around 0.015 eV from the baryon asymmetry criteria for normal hierarchy of neutrino masses.