Leptogenesis and low-energy phases

Abstract

In supersymmetric models, the CP asymmetry produced in the decay of the lightest right-handed neutrino, $\equiv epsilon$, can be written as a function of weak scale parameters. We introduce a way of separating epsilon into contributions from the various weak-scale phases, and study the contribution of potentially measurable neutrino phases to leptogenesis. We find that the Majorana phase phi', which could have observable effects on neutrinoless double beta decay, is important for epsilon unless there are cancellations among phases. If the phase delta can be measured at a neutrino factory, then it contributes significantly to epsilon over much of parameter space.