Generating the baryon asymmetry of the universe in split fermion models

The origin of the matter-antimatter asymmetry of the universe is one of the major unsolved problems in cosmology and particle physics. In this paper, we investigate the recently proposed possibility that split fermion models--extra dimensional models where the standard model fermions are localized to different points around the extra dimension--could provide a means to generate this asymmetry during the phase transition of the localizing scalars. After setting up the scenario that we consider, we use a single fermion toy model to estimate the reflection coefficients for scattering off the phase boundary using a more realistic scalar profile than previous work resulting in a different Kaluza-Klein spectrum. The value we calculate for nB/s is consistent with the mechanism being the source of the baryon asymmetry of our universe provided the B-L violating processes have an efficiency of order 10-5