Thu May 11 15:38:59 CDT 1995

Measurement of the fully corrected cross-section at the Fermilab Proton-Antiproton Collider

and the sum is over calorimeter energy clusters with corrected GeV as defined by the CDF jet clustering algorithm. The data sample corresponds to an integrated luminosity of . The error bars are statistical plus systematic added in quadrature.

The cross-section is compared with the predictions of next-to-leading order (NLO) quantum chromodynamics (QCD) (JETRAD). This is a next-to-leading order calculation.

The QCD curve is normalized to the data between =320-480 GeV. This normalization factor is of 1.65. Like the inclusive jet Et spectrum, the data has a smoothly increasing excess over QCD above 500 GeV. The systematic errors are shown as the shaded band at the bottom of the plot and the points have statistical error only. The large normalization factor indicates that the NLO calculation is not adequate to describe the observed rate of events in the spectrum. This is perhaps not surprising because for the jet cut that we are using (20 GeV) there are more three-jet events than two-jet events in our data sample.