Measurement of three-jet production cross-sections in [Formula: see text] collisions at 7 [Formula: see text] centre-of-mass energy using the ATLAS detector.

ABSTRACT

Double-differential three-jet production cross-sections are measured in proton-proton collisions at a centre-of-mass energy of [Formula see text] using the ATLAS detector at the large hadron collider. The measurements are presented as a function of the three-jet mass [Formula see text], in bins of the sum of the absolute rapidity separations between the three leading jets [Formula see text]. Invariant masses extending up to 5  TeV are reached for [Formula see text]. These measurements use a sample of data recorded using the ATLAS detector in 2011, which corresponds to an integrated luminosity of [Formula see text]. Jets are identified using the anti-[Formula see text] algorithm with two different jet radius parameters, [Formula see text] and [Formula see text]. The dominant uncertainty in these measurements comes from the jet energy scale. Next-to-leading-order QCD calculations corrected to account for non-perturbative effects are compared to the measurements. Good agreement is found between the data and the theoretical predictions based on most of the available sets of parton distribution functions, over the full kinematic range, covering almost seven orders of magnitude in the measured cross-section values.