Distinguishing dijet resonances at the LHC

Anticipating that a dijet resonance could be discovered at the 14 TeV LHC, we present two different strategies to reveal the nature of such a particle; in particular to discern whether it is a quark-antiquark (qq¯), quark-gluon (qg), or gluon-gluon (gg) resonance. The first method relies on the color discriminant variable, which can be calculated at the LHC from the measurements of the dijet signal cross section, the resonance mass, and the resonance width. Including estimated statistical uncertainties and experimental resolution, we show that a qg excited quark resonance can be efficiently distinguished from either a q¯q coloron or a gg color-octet scalar using the color discriminant variable at LHC-14. The second strategy is based on the study of the energy profiles of the two leading jets in the dijet channel. Including statistical uncertainties in the signal and the QCD backgrounds, we show that one can distinguish, in a model-independent way, between gg, qg, and qq¯ resonances; an evaluation of systematic uncertainties in the measurement of the jet energy profile will require a detailed detector study once sufficient 14 TeV dijet data are in hand.