p$_{T}$ unsmearing. After the jet energy scale and resolution smearing corrections, the observed data distribution has been corrected to the particle-level jets and is completely independent of the detector properties. The observed inclusive particle jet spectrum compared with the NLO pQCD predictions, corrected for underlying event and hadronization effects, is shown in Figure 3. The NLO pQCD predictions are calculated using NLOJet++ and FastNLO [16, 17] which use α 3 s ma- trix elements with µ$_{R}$ = µ$_{F}$ = p jet T . The parton distribution functions from CTEQ6.5M [49] are used, which include the Run I inclusive jet data. The dashed curve shows the NLO pQCD prediction calculation using MRST 2004 divided by the same calculated using CTEQ6.5M. The experimental uncertainty, dominated by the jet energy scale uncertainty, is 12% at p$_{T}$ = 50 GeV /c and 17% at p$_{T}$ = 550 GeV /c in the | y | < 0 . 4 bin. The uncertainty is higher in other y bins. These results are the most precise to-date. The main theoretical uncertainties arise from the uncertainty on the PDFs and the missing higher order terms in the perturbation series. As is customary, the effect of higher order terms is evaluated by varying the renormalization and factorization scale. Fortunately, the change in cross section from varying these scales is almost independent of the p$_{T}$ of the jets. The predicted cross section changed by ∼ 10 − 15% when the scale is changed to µ = 2 p$_{T}$ or µ = p$_{T}$/ 2. There is a good agreement between the data and the theoretical predictions over the whole p$_{T}$ range which spans 50 GeV /c to 550 GeV /c . Over this p$_{T}$ range, the cross sections falls by 10 orders of magnitude. The data prefers the lower bound of the theoretical prediction, favoring a smaller gluon content of the proton at high x . The theoretical uncertainty arising from the uncertainties in the parton distribution functions is larger than the experimental uncertainties. These data, along with CDF inclusive jet data, have been used in the global fits to improve the precision of the gluon distribution function. The results of these fits are described in Section V C. The CDF collaboration measured the inclusive jet cross section for a cone size of R = 0 . 7, using slightly more data, corresponding to 1.13 fb − 1 [46]. The measurement spans five rapidity bins | y | < 0 . 1 , 0 . 1 < | y | < 0 . 7 , 0 . 7 < | y | < 1 . 1 , 1 . 1 < | y | < 1 . 6 , 1 . 6 < | y | < 2 . 1. These bins are matched to the CDF calorimeter structure [11] and thus are different than the 2. CDF Collaboration 19