COVID-19 information for PI Residents and Visitors

Conference Date: 
Thursday, February 21, 2013 (All day) to Saturday, February 23, 2013 (All day)
Scientific Areas: 
Particle Physics

Jet substructure is a rapidly maturing subject at the LHC, with advances being made in the theory and measurements of jet properties. As our understanding of QCD jets improves, jet substructure is a potentially useful tool to search for beyond the Standard Model new physics at the LHC. This workshop will focus on recent progress on the theoretical understanding of the structure of jets in busy hadronic final states, the experimental status of substructure observables, and the applications to searches for new hadronic states at the LHC.

Sponsorship for this workshop has been provided by:

  • Haipeng An, Perimeter Institute
  • Cliff Burgess, Perimeter Institute & McMaster University
  • Timothy Cohen, Stanford University
  • David Curtin, Stony Brook University
  • Adam Davison, University College London
  • Andreas Hinzmann, Cern
  • Gregor Kasieczka, University of Heidelberg
  • Gordon Krnjaic, Perimeter Institute
  • David Krohn, Harvard University
  • Andrew Larkoski, Massachusetts Institute of Technology
  • Matt LeBlanc, TRIUMF
  • Peter Loch, University of Arizona
  • Timothy Lou, Princeton University
  • Matthew Low, University of Chicago
  • Gavin Salam, Cern
  • Sebastian Schaetzel, University of Heidelberg
  • Philip Schuster, Perimeter Institute
  • Yanwen Shang, Perimeter Institute
  • Jessie Shelton, Harvard University
  • Michael Spannowsky, Durham University
  • Maximilian Swiatlowski, Stanford University
  • Carlos Tamarit, Perimeter Institute
  • Emily Thompson, Cern
  • Natalia Toro, Perimeter Institute
  • Brock Tweedie, Boston University
  • Marcel Vos, Instituto De Fisica Corpuscular
  • Jacob Wacker, Stanford University
  • Lian Tao Wang, University of Chicago
  • Itay Yavin, Perimeter Institute & McMaster University



  • 8:30 am: Registration (Thursday only)
  • 9:00 am: Opening remarks by workshop organizers (Thursday only)
  • 9:15-11 am: Overview talks
  • 11-11:30 am: coffee break
  • 11:30 am-1:00 pm: introduction and motivation for discussions
  • 1:00-2:30 pm: lunch
  • 2:30-5:30 pm: small group discussions
  • 3:45-4:15: coffee break
  • 5-6 pm: reassemble, talk about outcome of discussions


  • 9 am-10:45 am: informal discussions, plans for future work
  • 10:45-11:15 am: coffee break
  • 11:15 am-1:00 pm: closing summary talks
  • 1:00 pm: lunch


Thursday: Marcel Vos, Jay Wacker

Friday: Andreas Hinzmann, Gavin Salam

Saturday: Peter Loch, Michael Spannowsky

DISCUSSION GROUPS (and possible talking points)


Survey of parameter space relevant for substructure searches and substructure variables

  • Status of theory space: what kinds of models are generally excluded or unconstrained? Are there gaps that could be covered in the immediate future?
  • Resolved vs. substructure analyses: which are most useful in different scenarios? Can the techniques be combined to strengthen constraints or discovery reach?
  • What are the most appropriate variables for substructure analyses? How can we better understand them?
  • What new variables are out there, and what kinds of physics do we need new variables to probe?

Understanding current substructure tools in relation to new physics searchers

  • Current jet substructure observables and tools
  • Is there redundancy in current substructure observables? What are the correlations between them?
  • How do variables behave over a broad range of pT scales? How does this affect background estimation?
  • What new variables are out there, and what kinds of physics do we need new variables to probe?
  • What is the best way to mitigate pile-up?
  • How do we balance robustness vs. discrimination power of substructure observables (as well as observables in resolved analyses)?


Data-driven estimates for substructure searches

  • Current approaches to experimental searches and comparisons to recommendations from theory/pheno
  • Methods for data-driven estimates used in these searches
  • Correlations between observables and the impact on data-driven estimates

Comparison of substructure variables used in searches

  • Comparison in the performance of different variables used in searches (current or future)
  • What figures of merit should be used when comparing experimental efficacy and performance?
  • To what extent are the effects of pile-up a limiting factor, and do searches require a more refined pile-up correction scheme (e.g. shape subtraction)?
  • Can we use new observables such as jet charge or ISR tagging in a real search? Are systematic uncertainties in any way a limiting factor?