# Quark and Gluon Tagging at the LHC

 Title: Quark and Gluon Tagging at the LHC Author: Gallicchio, Jason; Schwartz, Matthew D Note: Order does not necessarily reflect citation order of authors. Citation: Gallicchio, Jason and Matthew Schwartz. 2011. Quark and gluon tagging at the LHC. Physical Review Letters 107(17): 172001. Full Text & Related Files: 1106.3076v2.pdf (198.0Kb; PDF) Abstract: Being able to distinguish light-quark jets from gluon jets on an event-by-event basis could significantly enhance the reach for many new physics searches at the Large Hadron Collider. Through an exhaustive search of existing and novel jet substructure observables, we find that a multivariate approach can filter out over 95% of the gluon jets while keeping more than half of the light-quark jets. Moreover, a combination of two simple variables, the charge track multiplicity and the $$p_T$$-weighted linear radial moment (girth), can achieve similar results. Our study is only Monte Carlo based, so other observables constructed using different jet sizes and parameters are used to highlight areas that deserve further theoretical and experimental scrutiny. Additional information, including distributions of around 10 000 variables, can be found at http://jets.physics.harvard.edu/qvg/. Published Version: doi:10.1103/PhysRevLett.107.172001 Other Sources: http://arxiv.org/abs/1106.3076v2 Terms of Use: This article is made available under the terms and conditions applicable to Open Access Policy Articles, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#OAP Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:8160981

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Peer reviewed scholarly articles from the Faculty of Arts and Sciences of Harvard University