Implications of the CDF tbar{t} forward-backward asymmetry for hard top physics

摘要

The CDF collaboration has recently reported a large deviation from the standard model of the ( tbar{t} ) forward-backward asymmetry in the high invariant mass region. We interpret this measurement as coming from new physics at a heavy scale Λ, and perform a model-independent analysis up to ( mathcal{O}left( {{{1} left/ {{{Lambda^4}}} right.}} right) ). A simple formalism to test and constrain models of new physics is provided. We find that a large asymmetry cannot be accommodated by heavy new physics that does not interfere with the standard model. We show that a smoking gun test for the heavy new physics hypothesis is a significant deviation from the standard model prediction for the ( tbar{t} ) differential cross section at large invariant mass. At ( {M_{tbar{t}}} > 1;{text{TeV}} ) the cross section is predicted to be at least twice that of the SM at the Tevatron, and for ( {M_{tbar{t}}} > 1.5;{text{TeV}} ) at least three times larger than the SM at the LHC.