## Systematics of quark/gluon tagging

2017-07
Gras, P.
Höche, S.
Kar, D.
Larkoski, A.
Plätzer, S.
Siódmok, A.
Skands, P.
Soyez, G.
Thaler, J.
Springer Verlag
##### 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.
##### Keywords
Jets , QCD Phenomenology , EVENT SHAPE DISTRIBUTIONS , QCD ANALYTIC PREDICTIONS , GLUON JET PROPERTIES , QUARK JETS , HERWIG PLUS , POWER CORRECTIONS , 3-JET EVENTS , PARTON , DIPOLE , TESTS
##### Citation
Gras, P. et al. 2017. Systematics of quark/gluon tagging. JOURNAL OF HIGH ENERGY PHYSICS 2017(7), Article number 91.