Measurement of the Two-Jet Differential Cross Section in proton-antiproton Collisions at sqrt{s} = 1800 GeV

TL;DR

This paper reports a measurement of the two-jet differential cross section in proton-antiproton collisions at 1800 GeV, revealing discrepancies with existing next-to-leading order QCD predictions and challenging current parton distribution models.

Contribution

First measurement of the two-jet differential cross section at 1800 GeV in proton-antiproton collisions, testing QCD predictions with new data.

Findings

Measured cross section as a function of jet E_T and pseudorapidity.

Observed data do not agree well with next-to-leading order QCD calculations.

Results suggest need for improved parton distribution functions or theoretical models.

Abstract

A measurement is presented of the two-jet differential cross section, d^3\sigma/dE_T d\eta_1 d\eta_2, at center of mass energy sqrt{s} = 1800 GeV in proton-antiproton collisions. The results are based on an integrated luminosity of 86 pb^-1 collected during 1994-1995 by the CDF collaboration at the Fermilab Tevatron collider. The differential cross section is measured as a function of the transverse energy, E_T, of a jet in the pseudorapidity region 0.1 < |eta_1| < 0.7 for four different pseudorapidity bins of a second jet restricted to 0.1 < |\eta_2| < 3.0. The results are compared with next-to-leading order QCD calculations determined using the CTEQ4 and MRST sets of parton distribution functions. None of the sets examined in this analysis provides a good description of the data.