Measurement of jet activity in top quark events using the eμ final state with two b-tagged jets in pp collisions at √s=8 TeV with the ATLAS detector

The ATLAS collaboration

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Measurements of the jet activity in tt¯tt¯ events produced in proton-proton collisions at s√=8s=8 TeV are presented, using 20.3 fb−1 of data collected by the ATLAS experiment at the Large Hadron Collider. The events were selected in the dilepton eμ decay channel with two identified b-jets. The numbers of additional jets for various jet transverse momentum (pT) thresholds, and the normalised differential cross-sections as a function of pT for the five highest-pT additional jets, were measured in the jet pseudo-rapidity range |η| < 4.5. The gap fraction, the fraction of events which do not contain an additional jet in a central rapidity region, was measured for several rapidity intervals as a function of the minimum pT of a single jet or the scalar sum of pT of all additional jets. These fractions were also measured in different intervals of the invariant mass of the eμbb¯¯eμbb¯ system. All measurements were corrected for detector effects, and found to be mostly well-described by predictions from next-to-leading-order and leading-order tt¯tt¯ event generators with appropriate parameter choices. The results can be used to further optimise the parameters used in such generators.
Original languageEnglish
Article number74
Pages (from-to)1-62
Number of pages62
JournalJournal of High Energy Physics
Publication statusPublished - 13 Sept 2016

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