Top quark forward-backward asymmetry at the Tevatron: the electroweak contribution

TL;DR

This paper evaluates the electroweak contributions to the top quark forward-backward asymmetry at the Tevatron, showing they increase theoretical predictions and reduce discrepancies with experimental data.

Contribution

It provides a calculation of electroweak effects at order alpha^2 and alpha alpha_s^2, refining the theoretical prediction of the asymmetry.

Findings

Electroweak contributions increase the asymmetry prediction by ~20%.

Including electroweak effects reduces the deviation from experimental data.

Theoretical predictions align better with measurements after electroweak corrections.

Abstract

Recent CDF and D0 measurements of the top quark forward-backward asymmetry at the Tevatron present deviations between 1-sigma and 2-sigma from QCD predictions and a cut M_inv > 450 GeV on the events increases this deviation to 3.4 sigma in the CDF measurement. The inclusion of electroweak contributions of order alpha^2 and order alpha alphas^2 enlarges the theoretical prediction from QCD by a factor ~ 1.2 and diminishes the observed deviations. The calculation method is shortly discussed and numerical results are compared to the experimental data.