On the next-to-leading order QCD K-factor for top anti-top bottom anti-bottom production at the TeVatron

TL;DR

This paper calculates next-to-leading order QCD corrections for top-antitop plus two b-jets production at the TeVatron, showing small, stable corrections that impact background estimates for Higgs searches.

Contribution

It provides the first detailed NLO QCD correction analysis for top-antitop plus two b-jets production relevant to TeVatron experiments.

Findings

NLO corrections are small (~2%) and stable across cuts.

Distributions are distorted by up to 20% in some phase space regions.

The NLO K-factor is not necessarily applicable as a universal correction.

Abstract

Motivated by ongoing experimental analyses, we report on the calculation of next-to-leading order QCD corrections to the production of top anti-top pairs in association with two hard b-jets at the Fermilab TeVatron. Besides the total cross section and its scale dependence, a few differential distributions applicable for Higgs boson searches at the TeVaron are given. The QCD corrections with respect to leading order are negative and small. For our main setup they amount to 2%, and remain reasonably stable against changes of cuts. This proves that an integrated next-to-leading order K-factor does not necessarily need to be applied in the background estimation for the top anti-top H -> top anti-top bottom anti-bottom signal process. The distributions show similarly small corrections. The shape of kinematic distributions is distorted at most by about 20% in some corners of the phase space. Even though it is not the main purpose of this paper, we also evaluated the forward-backward asymmetry of the top quark at next-to-leading order.