Systematics of quark/gluon tagging

Gras, Philippe; Höche, Stefan; Kar, Deepak; Larkoski, Andrew; Lönnblad, Leif; Plätzer, Simon; Siódmok, Andrzej; Skands, Peter; Soyez, Gregory; Thaler, Jesse

Abstract

By measuring the substructure of a jet, one can assign it a “quark” or “gluon” tag. In the eikonal (double-logarithmic) limit, quark/gluon discrimination is determined solely by the color factor of the initiating parton (CF versus CA). In this paper, we confront the challenges faced when going beyond this leading-order understanding, using both parton-shower generators and first-principles calculations to assess the impact of higher-order perturbative and nonperturbative physics. Working in the idealized context of electron-positron collisions, where one can define a proxy for quark and gluon jets based on the Lorentz structure of the production vertex, we find a fascinating interplay between perturbative shower effects and nonperturbative hadronization effects. Turning to proton-proton collisions, we highlight a core set of measurements that would constrain current uncertainties in quark/gluon tagging and improve the overall modeling of jets at the Large Hadron Collider.

Citation

Gras, P., Höche, S., Kar, D., Larkoski, A., Lönnblad, L., Plätzer, S., …Thaler, J. (2017). Systematics of quark/gluon tagging. Journal of High Energy Physics, 2017(7), Article 91. https://doi.org/10.1007/jhep07%282017%29091

• Journal Article Type: Article
• Acceptance Date: Jul 5, 2017
• Online Publication Date: Jul 18, 2017
• Publication Date: Jul 18, 2017
• Deposit Date: Aug 4, 2017
• Publicly Available Date: Aug 4, 2017
• Journal: Journal of High Energy Physics
• Print ISSN: 1126-6708
• Publisher: Scuola Internazionale Superiore di Studi Avanzati (SISSA)
• Peer Reviewed: Peer Reviewed
• Volume: 2017
• Issue: 7
• Article Number: 91
• DOI: https://doi.org/10.1007/jhep07%282017%29091