Flavour violation in supersymmetric SO(10) unification with a type II seesaw mechanism

TL;DR

This paper investigates how supersymmetric SO(10) models with a type II seesaw mechanism predict lepton flavour violation and leptogenesis, providing testable signals like mu -> e gamma decay within experimental reach.

Contribution

It demonstrates that experimental bounds on flavour violation constrain leptogenesis and predict observable signals, integrating these predictions into a consistent SO(10) grand unified model.

Findings

Muon to electron gamma decay within MEG reach

Supersymmetric contribution to epsilon_K explains part of the experimental value

Model consistent with proton decay bounds and reproduces quark/lepton masses

Abstract

We study flavour violation in a supersymmetric SO(10) implementation of the type II seesaw mechanism, which provides a predictive realization of triplet leptogenesis. The experimental upper bounds on lepton flavour violating processes have a significant impact on the leptogenesis dynamics, in particular they exclude the strong washout regime. Requiring successful leptogenesis then constrains the otherwise largely unknown overall size of flavour-violating observables, thus yielding testable predictions. In particular, the branching ratio for mu -> e gamma lies within the reach of the MEG experiment if the superpartner spectrum is accessible at the LHC, and the supersymmetric contribution to epsilon_K can account for a significant part of the experimental value. We show that this scenario can be realized in a consistent SO(10) model achieving gauge symmetry breaking and doublet-triplet splitting in agreement with the proton decay bounds, improving on the MSSM prediction for alpha_3(m_Z), and reproducing the measured quark and lepton masses.