First Measurement of the Fraction of Top Quark Pair Production Through Gluon-Gluon Fusion

TL;DR

This paper reports the first measurement of the fraction of top quark pairs produced via gluon-gluon fusion at the Tevatron, using collision data from the CDF II detector, and finds results consistent with the Standard Model predictions.

Contribution

It provides the first experimental estimate of the gluon-gluon fusion contribution to top quark pair production at Tevatron energies.

Findings

Measured gluon-gluon fusion fraction: 0.07±0.14 (stat) ±0.07 (syst)

95% confidence level upper limit: 0.33

Result consistent with Standard Model prediction of 0.15±0.05

Abstract

We present the first measurement of the fraction of top quark pair production through gluon-gluon fusion. We use 0.96/fb of s**(1/2)=1.96 TeV p-pbar collision data recorded with the CDF II detector at Fermilab. We identify the candidate t-tbar events with a high-energy charged lepton, a neutrino candidate, and four or more jets. Using charged particles with low transverse momentum in t-tbar events, we find the fraction of top quark pair production through gluon-gluon fusion to be 0.07+/-0.14(stat)+/-0.07(syst), corresponding to a 95% confidence level upper limit of 0.33, in agreement with the standard model NLO prediction of 0.15+/-0.05.