Strategies to Identify Boosted Tops

By Jesse Thaler, Lian-tao Wang. 2008

243 citations recorded by the source corpus.

We study techniques for identifying highly boosted top jets, where the subsequent top decay products are not isolated. For hadronic boosted tops, we consider variables which probe the jet substructure in order to reduce the background from QCD jets with large invariant mass. Substructure variables related to two-body kinematics are least sensitive to the modeling of parton shower, while those which involve multi-body kinematics may still have discrimination power. For leptonic boosted tops, we consider variables which characterize the separation between the lepton—although not isolated by conventional criterion—and the hadronic activity in the top jet. Such variables are useful in reducing the backgrounds both from heavy-flavor jets and from accidental jet-lepton overlap. We give numerical estimates of the top identification efficiency versus background rejection rate as a functions of cuts on these variables, and find that these variables offer additional useful information above invariant mass alone.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/00e6240e44e2828ff08614c60682f0304481a8a1

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Citations in the corpus

Energy correlation functions for jet substructure (2013, methodology): “Recent substructure variables like planar flow [7, 9], Zernike coefficients [52], and Fox-Wolfram moments [53] are similarly sensitive to peculiar phase space configurations rather than prong-like substructure.”
Jet substructure at the Large Hadron Collider (2018, background): “In addition to the comprehensive studies of grooming options [57, 74, 86, 94, 95], ATLAS and CMS both investigated the discrimination powers for a plethora of jet substructure variables, including N -subjettiness [110, 111], Qjet volatility [154], ratios of energy correlation functions C 2 [117], D ”
Phenomenology of event shapes at hadron colliders (2010, background): “4) and to the event shapes studied for boosted top-quark identification [40, 42].”
Jet substructure at the Tevatron and LHC: new results, new tools, new benchmarksReport prepared by the participants of the BOOST 2011 Workshop at Princeton University, 22–26 May 2011. L Asquith (lasquith@hep.anl.gov), S Rappoccio (rappocc@fnal.gov) and C K Vermilion (verm@uw.edu), editors. (2011, methodology): “) • Planar flow is an interesting shape variable that was proposed to distinguish top and QCD jets [107, 75].”
Looking Inside Jets (2019, background): “ are energy correlation ratios [143,211]. ˝i and ˝ij are N-subjettiness variables and ratios respectively. RFW 2 is a Fox-Wolfram moment [212]. Splitting measures are denoted z cut, p d 12 and p d 23 [149,213]. The planar ow variable Pis dened in [214] and the angularity a 3 in [215]. Denitions can ”
Towards jetography (2009, methodology): “Method efficiency fake fraction (from [194]) just jet mass 50% 10% ATLAS [195, 196] 3,4 kt subjets, dcut 45% (85%) 5% (15%) Thaler & Wang [194] 2,3 kt subjets, zcut + shape 40% 5% Kaplan et al.”
Maximizing boosted top identification by minimizing N-subjettiness (2011, unknown): “The five algorithms shown in figure 1 are referred to as “Hopkins” [19], “CMS” [58–60], “Pruning” [27, 28], “ATLAS” [17, 61, 62], and “Thaler/Wang” [18].”
Efficient identification of boosted semileptonic top quarks at the LHC (2010, methodology): “The relative momentum of the muon in the μ+b system (zμ) is another simple variable [8], but we do not find that it gives a distinctive distribution compared to real tops.”
Boosted objects: a probe of beyond the standard model physics (2010, methodology): “Thaler and Wang [37] utilize a similar approach.”
Jet substructure at the Large Hadron Collider: A review of recent advances in theory and machine learning (2017, background): “[95] which calculated the jet planar flow [199, 250, 251], a measure of the aplanarity of the jet constituents, to LO.”
Energy flow polynomials: a complete linear basis for jet substructure (2017, background): “Useful observables can be constructed from the trace and determinant of C, such as planar flow Pf = 4 det C/(tr C)2 [101, 104], which is a ratio of two IRC-safe observables.”
Performance of jet substructure techniques for large-R jets in proton-proton collisions at $ \sqrt{s}=7 $ TeV using the ATLAS detector (2013, background): “For example, when sufficiently boosted, the decay products of W bosons [1], top quarks [2, 3], and Higgs bosons [4] can become collimated to the point that standard reconstruction techniques begin to fail.”