The forward-backward top asymmetry in a singlet extension of the MSSM

Abstract

The CDF and DØ collaborations have recently reported a large forward-backward asymmetry in the tt system which deviates from the next to-leading order QCD standard model prediction. We study the asymmetry in the tt system within the framework of singlet extensions of the Minimal Supersymmetric Standard Model. For this purpose, we introduce non-renormalizable couplings between first and third generation of quarks to scalars. We analyze two limiting cases of the model, characterized by the size of the supersymmetric mass for the singlet superfield. We study both the small and large limits of this mass parameter. We find that in the region of small singlet supersymmetric mass we can obtain a large asymmetry while being consistent with limits on the tt production cross section. These results are also consistent with constraints arising from flavor physics, quark masses and top quark decays.