Neutrino mass and leptogenesis in a type I + II seesaw model with spontaneous CP violation

Abstract

We propose a hybrid scenario incorporating type I and type II seesaw models for neutrino mass where CP symmetry has been broken by the complex vacuum expectation value of a singlet scalar field. Applying appropriate symmetries we show that such a framework can simultaneously explain the neutrino oscillation data and measured baryon asymmetry via leptogenesis. Further, the natural choice of parameters leads to a mixed leptogenesis scenario driven by nearly degenerate right handed singlet neutrino and scalar triplet fields for which we show a detailed analysis.

Scalar triplet leptogenesis with a CP violating phase

“…In the case of triplet leptogenesis, the flavor interplay comes to be very crucial [36] due to the unique decay channels of the scalar triplets. While flavored leptogenesis has already been studied in the framework of explicit CP violation [20], it is equally appealing to accommodate flavored leptogenesis through SCPV [17,34,38,42,48]. In this work, we explore the role of the SCPV via the complex VEV of the scalar sector in flavored leptogenesis.…”