On the Role of Low-Energy CP Violation in Leptogenesis

TL;DR

This paper explores how low-energy CP violation can drive successful leptogenesis within an adjoint SU(5) grand unified theory, especially under inverted neutrino mass hierarchy, linking experimental prospects to theoretical predictions.

Contribution

It demonstrates a strong connection between low-energy CP violation and leptogenesis in an adjoint SU(5) model with inverted hierarchy, highlighting testable predictions at the LHC.

Findings

Successful flavored leptogenesis favors low-energy CP violation.

Allowed triplet masses are highly restricted, making experimental detection feasible.

Potential signals include new states at LHC, proton decay, and gauge coupling unification.

Abstract

The link between low-energy CP violation and leptogenesis became more accessible with the understanding of flavor effects. However, a definite well-motivated model where such a link occurs was still lacking. Adjoint SU(5) is a simple grand unified theory where neutrino masses are generated through the Type I and Type III seesaw mechanisms, and the lepton asymmetry is generated by the fermionic triplet responsible for the Type III seesaw. We focus exclusively on the case of inverted hierarchy for neutrinos, and we show that successful flavored leptogenesis in this theory strongly points towards low-energy CP violation. Moreover, since the range of allowed masses for the triplet is very restricted, we find that the discovery at the LHC of new states present in the theory, together with proton decay and unification of gauge couplings, can conspire to provide a hint in favor of leptogenesis.