Forward Tevatron Tops and Backward LHC Tops with Associates

摘要

The anomalous forward-backward asymmetry (A_FB) in t tbar production at theTevatron is in apparent contradiction with the t tbar charge asymmetry (A_C)measurements at the LHC, which agree well with the standard model predictions.We argue that associated production of a state with [u tbar] flavor quantumnumbers can lead to a sizable negative contribution to A_C. Exchange of such aresonance in the t-channel would lead to positive contributions to A_FB andA_C, as has been extensively discussed in the literature. Given the additionalnegative A_C contribution, both the Tevatron and LHC data can be naturallyaccommodated within this framework. A simple realization of this setup is thewell known example of a Z' with flavor off-diagonal up-top couplings. Weprovide a detailed study of this model, demonstrating that it indeed reproducesthe t tbar asymmetry data, and is compatible with other constraints, e.g. t+jetresonance searches, t tbar inclusive jet multiplicities, and atomic parityviolation.