Inclusive jet cross sections in pbar p collisions at 630 and 1800 GeV

We have made a precise measurement of the inclusive jet cross section at {radical}s=1800 GeV. The result is based on an integrated luminosity of 92 pb-1 collected at the Fermilab Tevatron {anti p}p Collider with the D0 detector. The measurement is reported as a function of jet transverse energy (60 GeV {<=} ET {<=} 500 GeV ), and in the pseudo- rapidity intervals |{eta}| {<=} 0.5 and 0.1 {<=} |{eta}| {<=} 0.7. A preliminary measurement of the pseudorapidity dependence of inclusive jet production ( |{eta}| {<=} 1.5 ) is also discussed. The results are in good agreement with predictions from next-to-leading order (NLO) quantum chromodynamics (QCD). D0 has also determined the ratio of jet cross sections at {radical}s=630 GeV and {radical}s=1800 GeV ( |{eta}| {<=} 0.5). This preliminary measurement differs from NLO QCD predictions.