Systematics of quark/gluon tagging

Summary, in English

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 (C_F versus C_A). 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.

• Author: Philippe Gras; Stefan Höche; Deepak Kar; Andrew Larkoski; Leif Lönnblad; Simon Plätzer; Andrzej Siódmok; Peter Skands; Gregory Soyez; Jesse Thaler
• Department/s: Theoretical Particle Physics - Has been reorganised
• Publishing year: 2017-07-01
• Language: English
• Publication/Series: Journal of High Energy Physics
• Volume: 2017
• Issue: 7
• Links: http://dx.doi.org/10.1007/JHEP07(2017)091
• Document type: Journal article
• Publisher: Springer
• Topic: Subatomic Physics
• Keywords: Jets; QCD Phenomenology
• Status: Published
• Project: QCD Phenomenology and Event Generator Development; Innovative Network for Monte Carlo Event Generators for LHC Physics
• ISBN/ISSN/Other: ISSN: 1029-8479