The corrected normalized differential cross section distributions (1 /σ$_{dijet}$ · dσ/dχ$_{dijet}$ ) at the particle level are shown in Figure 12 for 10 dijet mass bins. The NLO pQCD predictions are computed using FastNLO [17] based on NLOJet++ [16]. These parton level predictions are corrected for the hadronization and underlying event contributions, which are evaluated using pythia . The theoretical uncertainties on the SM χ$_{dijet}$ distributions arising from the uncertainty on the PDFs and the uncertainty on renormalization and factorization scales are less than 2% and 5% respectively. These data are in good agreement with the SM predictions and thus are used to set exclusion limits in the parameter space of quark compositeness, ADD LED and TeV − 1 models. Calculations for all these models are available only at leading order, while pQCD calculations can be performed at next to leading order. For this analysis, the expected distributions for each new model are calculated at LO and then scaled by k - factors ( k = σ$_{NLO}$/σ$_{LO}$ ) determined from pQCD calculations. The k -factors vary from 1.25 to 1.5. All these models predict a higher rate as χ$_{dijet}$ → 1 and as m$_{jj}$ increases. However, the magnitude of the excess is different for different models. A Bayesian procedure [84] is used to obtain 95% C.L. limits on the mass scale parameters Λ, M$_{C}$ and M$_{S}$ in the above models. The results in which the prior is chosen to be flat in the model cross section are given in Table II. Other choices give similar but slightly higher limits [83]. The limits on M$_{C}$ obtained in this analysis are the first direct search for TeV − 1 extra dimensions at a particle collider, though inferior to indirect limits from precision electroweak measurements [81]. The limits on M$_{S}$ in different formalisms of ADD LED are on average slightly higher than the recent DØ results obtained using dielectron and diphoton data [85]. The quark compositeness limits are the most stringent limits to date. Since the start of the Run II, there has been a significant increase in the experimental data used in the jet analyses at the Tevatron. Due to the higher production cross section and the increase in available integrated luminosity, the inclusive jet cross section measurement has been extended to transverse momenta of 600 GeV /c . The experimental uncertainty is still dominated by the uncertainty on the jet energy scale which is +31/-26% in the p$_{T}$ = 457 − 527 GeV /c bin in 0 . 1 < | y | < 0 . 7 region for the CDF measurements and +16.0/- 15.5% in the p$_{T}$ = 490 − 540 GeV /c bin in | y | < 0 . 5 region for DØ measurements. Both VII. CONCLUSIONS 33