Speaker
Abstract:
We consider a model that includes light-colored scalars from the 45 and 50 representations of the SU(5) GUT gauge group in order to explain the CDF- and DO-reported ttbar forward-backward asymmetry (FBA). When the Yukawa coupling of the 50 is reasonably chosen and that of the 45 kept negligible at the scale of M_Z, our specific model yields phenomenologically viable results in agreement with the total ttbar FBA reported by CDF at the 0.7-sigma level and with the high mass bin ttbar FBA at the 2.2-sigma level. Additionally, the Yukawa coupling of the 50 remains perturbative to the GUT scale (which defines a "reasonably chosen" value at M_Z), and the presence of the light scalar from the 45 allows for gauge coupling unification at a GUT scale of ~ 10^17 GeV. We emphasize the reasonableness with which this model can be constructed with minimal extra SU(5) structure.
