Distinguishing Di-jet Resonances at the LHC

TL;DR

This paper proposes two methods to identify the nature of di-jet resonances at the 14 TeV LHC, using the color discriminant variable and jet energy profiles, to distinguish between qqbar, qg, and gg resonances.

Contribution

It introduces a novel approach combining the color discriminant variable and jet energy profiles for model-independent resonance identification at the LHC.

Findings

qg excited quark resonance can be distinguished from qqbar and gg resonances using the color discriminant variable.

Jet energy profiles can differentiate gg, qg, and qqbar resonances in a model-independent manner.

The methods account for statistical uncertainties and experimental resolutions.

Abstract

Anticipating that a di-jet 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 (qqbar), 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 di-jet 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 qqbar 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 di-jet 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 qqbar resonances; an evaluation of systematic uncertainties in the measurement of the jet energy profile will require a detailed detector study once sufficient 14 TeV di-jet data is in hand.