Quark-gluon Jet Discrimination At CMS

Many physics analyses at the LHC are looking into processes where the signal jets are originating from quarks, while jets in the background are more gluon enriched.Based on observables sensitive to fundamental differences in the fragmentation properties of gluons and quarks, a likelihood discriminant is construncted to distinguish between jets orginating from quarks and gluons.The performance of the tagger is evaluated using Z+jets and dijet events produced in proton-proton collisions at a centre-of-mass energy of 8 TeV, recorded by the CMS experiment at the LHC.