Forward Tevatron Tops and Backward LHC Tops with Associates
Abstract
The anomalous forward-backward asymmetry (AFB) in t tbar production at the Tevatron is in apparent contradiction with the t tbar charge asymmetry (AC) measurements at the LHC, which agree well with the standard model predictions. We argue that associated production of a state with [u tbar] flavor quantum numbers can lead to a sizable negative contribution to AC. Exchange of such a resonance in the t-channel would lead to positive contributions to AFB and AC, as has been extensively discussed in the literature. Given the additional negative AC contribution, both the Tevatron and LHC data can be naturally accommodated within this framework. A simple realization of this setup is the well known example of a Z' with flavor off-diagonal up-top couplings. We provide a detailed study of this model, demonstrating that it indeed reproduces the t tbar asymmetry data, and is compatible with other constraints, e.g. t+jet resonance searches, t tbar inclusive jet multiplicities, and atomic parity violation.