Measurement of the inclusive jet cross section with the ATLAS detector at the LHC

The measurement of the inclusive jet cross section is one of the test of perturbative quantum chromo-dynamics par excellence. The inclusive jet cross section presented in this thesis is measured with the ATLAS detector at the Large Hadron Collider (LHC). The double-differential inclusive jet cross section has been measured in bin of transverse momentum pT and rapidity |y|. It measures the cross sections for anti-kt jet with resolution parameter R = 0.4 and R = 0.6 for 20 GeV < pT < 1500 GeV, and for −4.4 < y < 4.4,which is the wider range reached so far at hadron collider. The total recorded integrated luminosity in 2010, used in this analysis, is almost 37 pb−1 . Four distinctive features make this measurement one of the more extensive and detailed tests of the jet physics at hadron colliders: (a) the measurement can profit of the unprecedented collision intensity and center-of-mass energy of sqrt(s) = 7 TeV provided by the Large Hadron Collider, overcoming the highest measured jet energies in previous experiments; (b) the wide solid angle coverage of the ATLAS experiment allow the measurement of the cross section in uncharted angular regions; (c) the quality of the ATLAS measurement of jets at low energies allow the extension of the cross section measurement to really low energy; (d) the jet cross section profits of the new anti-kt jet definition developed in the last couple of years, which overcame most of the problems of the previous definitions.