Pure Samples of Quark and Gluon Jets at the LHC

Abstract

Having pure samples of quark and gluon jets would greatly facilitate the study of jet properties and substructure, with many potential standard model and new physics applications. To this end, we consider multijet and jets (+ X) samples, to determine the purity that can be achieved by simple kinematic cuts leaving reasonable production cross sections. We find, for example, that at the 7TeV LHC, the (pp \to \gamma +2)jets sample can provide 98% pure quarkjets with 200 GeV of transverse momentum and a cross section of 5 pb. Toget 10 pb of 200 GeV jets with 90% gluon purity, the (pp \to 3) jets sample can be used. (b+2)jets is also useful for gluons, but only if the b-tagging is very efficient.