pp interactions at the ATLAS experiment at the LHC accelerator

In this thesis the potential of the ATLAS detector to exclude or discover quark compositeness is studied in detail. There were four different sensitive analysis methods developed for this purpose. These methods use a detailed information about inclusive dijet pT-spectrum or dijet angular distribution and two of them use Bayesian technique (as is usual in similar analyses at Tevatron). For all four methods a larger number of systematic errors was taken into account and their influence was studied in detail too. It is also shown, that the early data exclusion limit on quark compositeness reachable by the ATLAS experiment is Λ+LL = 10.3 TeV at 95% C.L with 100 pb−1 of collision data of a sufficient quality. This limit is considerably higher than the current limit known from Tevatron: Λ+LL = 2.7 TeV at 95% C.L. The highest exclusion limit on quark compositeness with expected total amount of data to be collected by the ATLAS experiment is above 22 TeV, assuming 3% jet energy scale uncertainty.