Associated jet and subjet rates in light-quark and gluon jet discrimination

Abstract

We show that in studies of light quark- and gluon-initiated jet discrimination, it is important to include the information on softer reconstructed jets (associated jets) around a primary hard jet. This is particularly relevant while adopting a small radius parameter for reconstructing hadronic jets. The probability of having an associated jet as a function of the primary jet transverse momentum ($p_T$) and radius, the minimum associated jet $p_T$ and the association radius is computed upto next-to-double logarithmic accuracy (NDLA), and the predictions are compared with results from Herwig++, Pythia6 and Pythia8 Monte Carlos (MC). We demonstrate the improvement in quark-gluon discrimination on using the associated jet rate variable with the help of a multivariate analysis. The associated jet rates are found to be only mildly sensitive to the choice of parton shower and hadronization algorithms, as well as to the effects of initial state radiation and underlying event. In addition, the number of $k_T$ subjets of an anti-$k_T$ jet is found to be an observable that leads to a rather uniform prediction across different MC's, broadly being in agreement with predictions in NDLA, as compared to the often used number of charged tracks observable.

25 pages, 12 figures; v2: Figures of 2D joint distributions included, additions to text and Refs., version to appear in JHEP

References in corpus (7)

• PYTHIA 6.4 Physics and Manual
• An Introduction to PYTHIA 8.2
• Herwig++ Physics and Manual
• Gaining (Mutual) Information about Quark/Gluon Discrimination
• Non-perturbative QCD effects in jets at hadron colliders
• Multivariate discrimination and the Higgs + W/Z search
• Gluon- and Quark-Jet Multiplicities with NNNLO and NNLL Accuracy

Cited by in corpus (15)

• New Angles on Energy Correlation Functions
• Quark-Gluon tagging with Shower Deconstruction: Unearthing dark matter and Higgs couplings
• A Fragmentation Approach to Jet Flavor
• Quark-gluon discrimination in the search for gluino pair production at the LHC
• A case study of quark-gluon discrimination at NNLL' in comparison to parton showers
• Machine Learning in High Energy Physics: A review of heavy-flavor jet tagging at the LHC
• Lund and Cambridge multiplicities for precision physics
• Jet tagging algorithm of graph network with HaarPooling message passing
• Lund multiplicity in QCD jets
• Jet Tagging with More-Interaction Particle Transformer
• Dissecting Multi-Photon Resonances at the Large Hadron Collider
• Jet Classification Using High-Level Features from Anatomy of Top Jets
• Boosted top tagging and its interpretation using Shapley values
• Experimental Verification of Two types of Gluon Jets in QCD
• Power Counting Energy Flow Polynomials