Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Boosted objects and jet substructure at the LHC

BOOST2012 participants- A. Altheimer, A. Arce, L. Asquith, J. Backus Mayes, E. Bergeaas Kuutmann, J. Berger, D. Bjergaard, L. Bryngemark, A. Buckley, J. Butterworth, M. Cacciari, M. Campanelli, T. Carli, M. Chala, B. Chapleau, C. Chen, J. P. Chou, Th. Cornelissen, D. Curtin, M. Dasgupta, A. Davison, F. de Almeida Dias, A. de Cosa, A. de Roeck, C. Debenedetti, C. Doglioni, S. D. Ellis, F. Fassi, J. Ferrando, S. Fleischmann, M. Freytsis, M. L. Gonzalez Silva, S. Gonzalez de la Hoz, F. Guescini, Z. Han, A. Hook, A. Hornig, E. Izaguirre, M. Jankowiak, J. Juknevich, M. Kaci, D. Kar, G. Kasieczka, R. Kogler, A. Larkoski, P. Loch, D. Lopez Mateos, S. Marzani, L. Masetti, V. Mateu, D. W. Miller, K. Mishra, P. Nef, K. Nordstrom, E. Oliver Garcia, J. Penwell, J. Pilot, T. Plehn, S. Rappoccio, A. Rizzi, G. Rodrigo, A. Safonov, G. P. Salam, J. Salt, S. Schaetzel, M. Schioppa, A. Schmidt, J. Scholtz, A. Schwartzman, M. D. Schwartz, M. Segala, M. Son, G. Soyez, M. Spannowsky, I. Stewart, D. Strom, M. Swiatlowski, V. Sanchez Martinez, M. Takeuchi, J. Thaler, E. Thompson, N. V. Tran, C. Vermilion, M. Villaplana, M. Vos, J. Wacker, J. Walsh

TL;DR

The BOOST2012 report surveys jet substructure at the LHC from four angles: first-principle QCD predictions, Monte Carlo modeling, pile-up effects, and boosted-top phenomenology. It documents advances in analytical resummation (pQCD and SCET), empirical jet-substructure measurements by ATLAS and CMS, and systematic MC comparisons, highlighting grooming as a key tool to mitigate pile-up. The work also demonstrates the promise of boosted-top tagging for enhancing searches for heavy resonances and new physics, while identifying remaining theoretical and experimental uncertainties, especially in large-R jet systematics and non-global logarithms. Overall, the document argues that a combination of refined analytic calculations, improved MC description, and robust pile-up/grooming strategies will sharpen the LHC’s ability to exploit jet substructure for discovery and precision studies.

Abstract

This report of the BOOST2012 workshop presents the results of four working groups that studied key aspects of jet substructure. We discuss the potential of the description of jet substructure in first-principle QCD calculations and study the accuracy of state-of-the-art Monte Carlo tools. Experimental limitations of the ability to resolve substructure are evaluated, with a focus on the impact of additional proton proton collisions on jet substructure performance in future LHC operating scenarios. A final section summarizes the lessons learnt during the deployment of substructure analyses in searches for new physics in the production of boosted top quarks.

Boosted objects and jet substructure at the LHC

TL;DR

The BOOST2012 report surveys jet substructure at the LHC from four angles: first-principle QCD predictions, Monte Carlo modeling, pile-up effects, and boosted-top phenomenology. It documents advances in analytical resummation (pQCD and SCET), empirical jet-substructure measurements by ATLAS and CMS, and systematic MC comparisons, highlighting grooming as a key tool to mitigate pile-up. The work also demonstrates the promise of boosted-top tagging for enhancing searches for heavy resonances and new physics, while identifying remaining theoretical and experimental uncertainties, especially in large-R jet systematics and non-global logarithms. Overall, the document argues that a combination of refined analytic calculations, improved MC description, and robust pile-up/grooming strategies will sharpen the LHC’s ability to exploit jet substructure for discovery and precision studies.

Abstract

This report of the BOOST2012 workshop presents the results of four working groups that studied key aspects of jet substructure. We discuss the potential of the description of jet substructure in first-principle QCD calculations and study the accuracy of state-of-the-art Monte Carlo tools. Experimental limitations of the ability to resolve substructure are evaluated, with a focus on the impact of additional proton proton collisions on jet substructure performance in future LHC operating scenarios. A final section summarizes the lessons learnt during the deployment of substructure analyses in searches for new physics in the production of boosted top quarks.

Paper Structure

This paper contains 32 sections, 6 equations, 8 figures, 2 tables.

Table of Contents

  1. Introduction
  2. Measurements and first-principle QCD predictions for jet substructure
  3. Jet Substructure Measurements by ATLAS
  4. Jet Substructure Measurements by CMS
  5. Analytical predictions for jet substructure
  6. Resummation in pQCD
  7. Resummation in SCET
  8. Discussion and recommendations for further substructure measurements
  9. Monte Carlo Generators for Jet Substructure Observables
  10. Monte Carlo samples and tools
  11. Jet mass
  12. Jet substructure observables
  13. Colour flow
  14. Jet charge
  15. Summary
  16. ...and 17 more sections

Figures (8)

  • Figure 1: The jet invariant mass distribution for the leading jet in the boosted semileptonic $t\overline{t}$ event sample, before and after jet grooming.
  • Figure 2: The distribution of four different measures of jet substructure for leading jet of a boosted semileptonic top sample. The C-A algorithm is used in reclustering, as mentioned in the text.
  • Figure 3: Upper row: Comparison of colour-flow observables: pull angle of leading jet attributed to the hadronic W decay in $t\overline{t}$ events, and dipolarity of leading jet produced in association with a leptonically decaying W. Lower row: Comparison of jet charge observables ($\kappa=0.3$): charge observable for leading jet produced in association with a leptonically decaying W (left panel), and sum of jet charge observables for the two jets attributed to the hadronic W decay in $t\overline{t}$ events (right panel).
  • Figure 4: The fraction of pile-up jet s with $R_{p_T} > 0.8$ (QCD-like) as a function of the number of minimum-bias interactions per event for different values of $p_T^{corr}$. A fit of the exponential form $f=c_0+c_1\exp(c_2\cdot N_{\rm PV})$ is superposed where one degree of freedom is fixed via the constraint $f(0)=1$, i.e. $c_1=(1-c_0)$.
  • Figure 5: The mean number of pileup jets per event inclusively \ref{['fig:pujetmult:0']} and for QCD-like pileup jets with $R_{p_T} > 0.8$\ref{['fig:pujetmult:1']}, as a function of $\mu$ and $p_T^{corr}$.
  • ...and 3 more figures