Multijet Jet Transverse-Momentum Distributions
The observed jet transverese-momentum distributions for CDF events with total
transverse energy exceeding 420 GeV extend out to pTs of about
500 GeV/c. The pT distributions for two-, three-, four-, five-,
and six-jet events exhibit peaks at about 200 GeV, reflecting two-jet
dominance in a sample with total Et > 420 GeV. The three-, four-, five-,
and six-jet distributions also exhibit peaking towards low jet pT,
reflecting the soft gluon radiation pole in the QCD matrix element.
The leading order QCD matrix element calculations give good descriptions
of the observed multijet jet-pT distributions. The HERWIG parton shower
Monte Carlo predictions do not seem to give good descriptions of the
three-jet and four-jet distributions, where too many jets are predicted
at intermediate pTs.
Multijet Jet Pt Figure
Figure caption: Exculsive multijet jet-Pt distributions for events
containing two, three, four, five, and six jets with transverse
energy > 20 GeV. The CDF data
(solid points) are compared with HERWIG predictions (histograms)
and NJETS predictions (8 curves for 8 different parameter choices)
for events with total-transverse-energy
exceeding 420 GeV, multijet mass > 600 GeV, and
leading-jet scattering angle such that cos theta < 0.67.
More information can be found in
prl 75, 608 (1995)