Implications of the CDF t(t)over-bar forward-backward asymmetry for boosted top physics

Abstract

New physics at a high scale A can affect top-related observables at O(1/Lambda(2)) via the interference of effective four quark operators with the SM amplitude. The ((u) over bar gamma(mu)gamma(5)T(a)u)((t) over bar gamma(mu)gamma(5)T(a)t) operator modifies the large M-(u) over bar forward-backward asymmetry, and can account for the recent CDF measurement. The ((u) over bar gamma(mu)T(a)u)((t) over bar gamma(mu)T(a)t) operator modifies the differential cross section, but cannot enhance the cross section of ultra-massive boosted jets by more than 60%. The hint for a larger enhancement from a recent CDF measurement may not persist future experimental improvements, or may be a QCD effect that is not accounted for by leading order and matched Monte Carlo tools or naive factorization. If it comes from new physics, it may stem from new light states or an O(1/Lambda(4)) new physics effect. (C) 2011 Elsevier B.V. All rights reserved.