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Playing tag with ANN: boosted top identification with pattern recognition

  • Leandro G. Almeida
  • Mihailo Backović
  • Mathieu Cliche
  • Seung J. Lee
  • Maxim PerelsteinEmail author
Open Access
Regular Article - Theoretical Physics

Abstract

Many searches for physics beyond the Standard Model at the Large Hadron Collider (LHC) rely on top tagging algorithms, which discriminate between boosted hadronic top quarks and the much more common jets initiated by light quarks and gluons. We note that the hadronic calorimeter (HCAL) effectively takes a “digital image” of each jet, with pixel intensities given by energy deposits in individual HCAL cells. Viewed in this way, top tagging becomes a canonical pattern recognition problem. With this motivation, we present a novel top tagging algorithm based on an Artificial Neural Network (ANN), one of the most popular approaches to pattern recognition. The ANN is trained on a large sample of boosted tops and light quark/gluon jets, and is then applied to independent test samples. The ANN tagger demonstrated excellent performance in a Monte Carlo study: for example, for jets with p T in the 1100-1200 GeV range, 60% top-tag efficiency can be achieved with a 4% mis-tag rate. We discuss the physical features of the jets identified by the ANN tagger as the most important for classification, as well as correlations between the ANN tagger and some of the familiar top-tagging observables and algorithms.

Keywords

Jets 

Notes

Open Access

This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.

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Copyright information

© The Author(s) 2015

Authors and Affiliations

  • Leandro G. Almeida
    • 1
  • Mihailo Backović
    • 2
  • Mathieu Cliche
    • 3
  • Seung J. Lee
    • 4
    • 5
  • Maxim Perelstein
    • 3
    Email author
  1. 1.Institut de Biologie de l’ École Normale Supérieure (IBENS), Inserm 1024- CNRS 8197ParisFrance
  2. 2.Center for CosmologyParticle Physics and Phenomenology - CP3, Universite Catholique de LouvainLouvain-la-neuveBelgium
  3. 3.Laboratory for Elementary Particle PhysicsCornell UniversityIthacaUnited States
  4. 4.Department of PhysicsKorea Advanced Institute of Science and TechnologyDaejeonSouth Korea
  5. 5.School of PhysicsKorea Institute for Advanced StudySeoulSouth Korea

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