Comparison of Three-jet Events in Proton-Antiproton Collisions at sqrt{s}=1.8 TeV to Predictions from a Next-to-leading Order QCD Calculation

TL;DR

This paper compares three-jet event data from proton-antiproton collisions at 1.8 TeV with next-to-leading order QCD predictions, testing higher order effects and measuring cross sections.

Contribution

It provides the first detailed comparison of three-jet event properties with NLO QCD calculations at Tevatron energies, including differential cross sections across the Dalitz plane.

Findings

Measured total cross section: 466 pb with uncertainties.

Differential cross sections generally agree with predictions.

Some shape differences observed in the Dalitz plane.

Abstract

The properties of three-jet events with total transverse energy greater than 320 GeV and individual jet energy greater than 20 GeV have been analyzed and compared to absolute predictions from a next-to-leading order (NLO) perturbative QCD calculation. These data, of integrated luminosity 86 pb^-1, were recorded by the CDF Experiment for proton-antiproton collisions at sqrt{s}=1.8 TeV. This study tests a model of higher order QCD processes that result in gluon emission and can be used to estimate the magnitude of the contribution of processes higher than NLO. The total cross section is measured to be 466 \pm 3(stat.)^{+207}_{-70}(syst.) pb. The differential cross section is furthermore measured for all kinematically accessible regions of the Dalitz plane, including those for which the theoretical prediction is unreliable. While the measured cross section is consistent with the theoretical prediction in magnitude, the two differ somewhat in shape in the Dalitz plane.