Systematics of quark/gluon tagging
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 (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.
Keywords
Cite
@article{arxiv.1704.03878,
title = {Systematics of quark/gluon tagging},
author = {Philippe Gras and Stefan Höche and Deepak Kar and Andrew Larkoski and Leif Lönnblad and Simon Plätzer and Andrzej Siódmok and Peter Skands and Gregory Soyez and Jesse Thaler},
journal= {arXiv preprint arXiv:1704.03878},
year = {2017}
}
Comments
50 pages, 20 figures, extended version of the Les Houches 2015 study from arXiv:1605.04692; v2: updated to approximately match journal version, including improved discussion of nonperturbative Casimir scaling and more umlauts