Measurement of the fraction of top quark pair events produced via gluon-gluon fusion at the Tevatron in lepton+jets final states

TL;DR

This paper measures the proportion of top quark pairs produced via gluon-gluon fusion at the Tevatron, using a boosted decision tree to distinguish production mechanisms in lepton+jets final states with full RunII data.

Contribution

It introduces a method employing a boosted decision tree and template fitting to quantify the gluon-gluon fusion contribution in top quark pair production.

Findings

Gluon-gluon fusion fraction is approximately 9.6%.

The measurement has a statistical uncertainty of 3.9%.

Systematic uncertainties range from -6.2% to +7.7%.

Abstract

We report a measurement of the fraction of top quark pair events produced via gluon-gluon fusion in $p\bar{p}$ collisions at $\sqrt{s} = 1.96 ~\rm TeV$ in lepton+jets final states using the full RunII data set corresponding to $9.7 ~\rm fb^{-1}$ of integrated luminosity collected by the D\O\ experiment. We utilize a boosted decision tree to distinguish top quark pair events produced by $q\bar{q}$ annihilation and $gg$ fusion. We perform a template fit to extract the $t\bar{t}$ production fraction via $gg$ fusion and find $f_{gg} = 0.096 \pm 0.039 ~(\rm stat.) ~^{+0.077}_{-0.062} ~(\rm syst.)$.