Measurements of multijet production cross sections in proton-proton collisions at 7 TeV center-of-mass energy with the ATLAS Detector

Inclusive multijet production has been studied with the ATLAS detector in proton-proton collisions at a center-of-mass energy of 7 TeV, using an integrated luminosity of 17 nb$^{-1}$. The anti-$k_t$ algorithm with distance parameter $R=0.6$ is used to identify jets. The inclusive multijet cross section is measured, as well as the ratio of cross sections for inclusive production of $n-1$ and $n$ jets for $n\leq 6$. The differential cross sections of the first, second, third and fourth leading jets as a function of transverse momentum, and the differential cross section as a function of the scalar sum of the $p_T$ of selected jets, $H_T$, for different jet multiplicities are presented. The ratio of the differential cross section as a function of $H_T$ for 3-jet and 2-jet events is also measured. The results are compared to expectations based on leading order QCD, which agree with the data.