Tools and Monte Carlo Session 1 (SM)

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(Projects at Les Houches)
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** Theoretical: uncertainty bands, errors
** Theoretical: uncertainty bands, errors
** Specifically for matching and matching procedures
** Specifically for matching and matching procedures
** Experimental: contraints, validation, tuning uncertainties
** Experimental: contraints, validation, tuning uncertainties: see [[Systematic Evaluation of Errors on tunes]]
** Technical: usage and design
** Technical: usage and design
** Uncertainty bands for Monte Carlos: see [[Systematic Evaluation of Errors on tunes]]
** Uncertainty bands for Monte Carlos: see [[Systematic Evaluation of Errors on tunes]]

Revision as of 11:40, 15 June 2009

Conveners present: Peter Skands, Fabio Maltoni, Jon Butterworth
(Click here for Tools and Monte Carlo Session 2 (BSM))



Validity of tunes and Uncertainty Bands

Automated Tuning: Rivet & Professor

Toolkit for validation of Monte Carlo event generators. Using an computationally efficient model for observable computations, Rivet provides a set of experimental analyses useful for generator sanity checks, as well as a convenient infrastructure for adding your own analyses. Rivet's design emphasises the separation between HepMC records and where they came from, allowing it to be a completely cross-generator validation platform. Rivet 1.1.3 was just released (9 June).

A rivet tutorial (Andy Buckley) was given 16:00 Thursday in the QCD room.

Professor is a MC tuning tool, developed in Python as a set of command line programs and an underlying library. The Rivet toolkit is used to generate MC data and retrieve experimental reference data.

Systematic Evaluation of Errors on tunes

The title is a link.

Important data sets for tuning

Follow the link above.

Multiple Parton Interactions

  • W+jets from MPI (E. Maina, R. Chierici, S. Plaetzer, P. Skands, K. Mazumdar, S.Gieseke)

Tuning in the presence of matching

Follow the link above.

Model (in)dependence in Data/Theory Comparisons

Fast Detector Simulation Specification and Usage

This is joint with Session 2; see also: Tools_and_Monte_Carlo_Session_2_(BSM)#Detector_simulation_.28with_Session_1.29

Data Correction and Unfolding


Projects at Les Houches

  • A Collection of Matching Benchmarks
    • So far declared interest: F. Maltoni, P. Skands, S. Hoeche, K. Hamilton, S. Plaetzer, S. Mrenna, L. Lonnblad, P. Francavilla, J. Winter, M. Schwarz, P. Lenzi...
    • Overview of systematic studies so far (Z/W+jets, ttbar, Z->qqbar)
    • Why it's not a complete set
      • gg initial states (Higgs, with NLM Higgs)
      • gluon splitting (Zbbbar, Wbbbar) (G. Piacquadio)
      • distinguish between W+ and W- at LHC
      • QCD n-jets (P. Francavilla)
      • New Physics Benchmarks?
    • Comparison of NLO (e.g., MCFM, MC@NLO, POWHEG) with tree-level calculations (e.g., Madgraph, Alpgen, with and without showers) (e.g., for Higgs) (J. Winter, P. Lenzi)
    • Pathological Observables / Theory Tests : (P. Skands, S. Weinzierl, S. Plaetzer, K. Hamilton, M. Schwarz, ...)
      • To test Higher-Order/Higher-Log properties of matching
      • To test Coherence/Subleadling-Logs dependence on Shower Model (new PS models)
    • Complete set of observables? (not only pT and rapidity, but jet-jet correlations, jet masses, jet-jet Delta(R), etc)
    • Sensitivity to tuning (with Tuning subgroup)
  • QED/EW ME/PS Matching
    • So far declared interest: S. Gascon, F. Piccinini, C. Baty, S. Ferrag, K. Mazumdar...
  • LHEF for Matching
    • So far declared interest: L. Lonnblad, T. Sjostrand, F. Maltoni, S. Platzer, S. Hoeche, K. Hamilton, A. Buckley, J. Huston...
    • Possible to agree on Standard for describing, in Les Houches Event Files, properties and cuts used in ME generation that subsequent matching steps based on jet clustering would need to know about?
    • Possibly including NLO
  • Automated ME/PS merging
    • So far declared interest: S. Mrenna, P. Skands, S. Hoeche, K. Hamilton, S. Plaetzer
    • Automating 1st-order correction factors for showers from automatic evaluation of |M(X+1)|^2/|M(X)|^2 from an ME generator.
    • Automated merging for BSM (with session 2)
  • Discussion on MC Uncertainties (with EX/TH and tuning subgroups)
  • NLO Matching Discussion
    • Multileg matching at NLO, state of the field
    • What is needed for automating NLO matching?

Matching Beyond Fixed Orders

That title is a link.

Wbb in the high pT HW region

That title is a link.

Parton Densities

PDFs in Monte Carlos

  • Exploring the LO* PDFs, are we ready to use them for production?
  • Uncertainty Bands for the LO* PDFs
  • PDFs and their interaction with MC tuning
  • Pythia 8 - Advantages/disadvantages of using one PDF for hard scattering ME (best cross section?) and another for evolution (universal tuning?)

Beyond LO*

  • Are PDFs ready for NLO/Multileg WG?
  • Electroweak and QCD in PDFs
  • BSM effects in PDFs (with Session 2)

Heavy quark PDF's

  • HQ initiated processes vis-a-vis latest implementation of HQ PDF's(Session 1)

Jet Physics

For discussion of calibration and truth level, see the session on Data/Theory comparison Tools_and_Monte_Carlo_Session_1_(SM)#Data_Correction_and_Unfolding

A very recent pedagogical review of jets, new algorithms and substructure.

Jet Substructure

Boosted hadronic decays of massive particles (W,Z,Top,H,BSM..., with session 2) and jet mass/shape studies with QCD jets in early data.

The title above is a link.

Study of radiation between jets, for colour singlet and colour octet exchange

The title above is a link.

Standard Processes for Early LHC Data (Joint with NLO/Multileg)

In the introduction session, the proposal was made that some standard processes should be listed, and in additona a subset of these should followed through the various MC and NLM sessions, to review the impact of the various issues ((N)NLO, Matching, PDFs, jet definition, EW corrections...) on the process. This is probably a cross-group activity which should be migrated to a separate page but is here for now as a reminder.

List based on my poor memory, to be amended...

  • Drell-Yan (Samir Ferrag...)
  • ttbar (Kajari Mazumdar, Rohini Godbole...)
  • W/Z ratios etc (Bruce Mellado...)
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