Monte Carlo event generators for LHC physics

Slides:



Advertisements
Similar presentations
Monte Carlo Event Generators
Advertisements

CERN 29 th March1 HERWIG Peter Richardson IPPP, Durham University Herwig++
Monte Carlo event generators for LHC physics Mike Seymour University of Manchester CERN Academic Training Lectures July 7 th – 11 th 2003
Monte Carlo Simulation of Collisions at the LHC Michael H. Seymour University of Manchester & CERN 5th Vienna Central European Seminar on Particle Physics.
Bonn 23 rd Feb1 Simulations of BSM Signals Peter Richardson IPPP, Durham University.
Wine & Cheese Seminar 17 th March1 Recent Developments in Monte Carlo Event Generators Peter Richardson IPPP, Durham University Durham University.
Les Houches 12 th June1 Generator Issues Peter Richardson IPPP, Durham University.
M. Lefebvre25 October QCD Multijet Event Generation MLM prescription for the removal of event double counting M. Lefebvre University of Victoria.
Les Houches 14 th June1 Matching Matrix Elements and Parton Showers Peter Richardson IPPP, Durham University.
Monte Carlo Event Generators
Recent Advances in QCD Event Generators
Collider Physics and QCD Phenomenology Mike Seymour (based at CERN) HERWIG Monte Carlo event generator –Current version ~ frozen (bug fixes and minor new.
Working group C summary Hadronic final states theory Mrinal Dasgupta.
Monte Carlo event generators for LHC physics Mike Seymour University of Manchester CERN Academic Training Lectures July 7 th – 11 th 2003
Cambridge 19 th April1 Comparisons between Event Generators and Data Peter Richardson IPPP, Durham University.
Olivier RavatLes Houches/June 3rd Higgs associated production at LHC : Thecase Olivier Ravat, Morgan Lethuillier IPN Lyon Les Houches 2003 : Physics.
Feynman Festival August 23, 2002 Rick Field - Florida/CDFPage 1 Toward an Understanding of the Overall Event Structure of Hard Collisions  The Past:
Run 2 Monte-Carlo Workshop April 20, 2001 Rick Field - Florida/CDFPage 1 The Underlying Event in Hard Scattering Processes  The underlying event in a.
Fermilab MC Workshop April 30, 2003 Rick Field - Florida/CDFPage 1 The “Underlying Event” in Run 2 at CDF  Study the “underlying event” as defined by.
CKKW studies and other news J. Huston Michigan State University (with help from Ben Cooper and Bruce Mellado)
D0 Meeting September 6, 2002 Rick Field - Florida/CDFPage 1 The “Underlying Event” in Hard Scattering Processes  What happens when a proton and an antiproton.
Sheffield Seminar 23 rd November1 Monte Carlos for LHC Physics Peter Richardson IPPP, Durham University Durham University.
Models Experiment Bridging the Gap Tim Stelzer Fabio Maltoni + CP 3.
SHERPA Simulation for High Energy Reaction of PArticles.
Aachen, November 2007 Event Generators 3 Practical Topics Peter Skands CERN / Fermilab.
Moriond 20 th March1 Herwig++ Peter Richardson IPPP, Durham University S. Gieseke, D. Grellscheid, K. Hamilton, A. Ribon, PR, P. Stephens, M.H. Seymour,
St. Andrews, Scotland August 22, 2011 Rick Field – Florida/CDF/CMSPage Rick Field University of Florida Outline  Do we need a.
1 Update on tt-bar signal and background simulation Stan Bentvelsen.
Andrey Korytov, University of Florida ISMD 2003 September 5-11, 2003, Kraków Soft QCD Phenomena in High-E T Jet Events at Tevatron Andrey Korytov for CDF.
PIC 2011, Vancouver August 29, 2011 Rick Field – Florida/CDF/CMSPage 1 Physics in Collision Rick Field University of Florida Outline  Examine.
Tools08 1 st July1 PDF issues for Monte Carlo generators Peter Richardson IPPP, Durham University.
ICHEP 2012 Melbourne, July 5, 2012 Rick Field – Florida/CDF/CMSPage 1 ICHEP 2012 Rick Field University of Florida Outline of Talk CMS at the LHC CDF Run.
TeV4LHC - Fermilab October 20, 2005 Rick Field - Florida/CDFPage 1 TeV4LHC Workshop Rick Field University of Florida CDF Run 2 Talk #1.
ISMD2004 July 27, 2004 Rick Field - Florida/CDFPage 1 International Symposium on Multiparticle Dynamics Rick Field (theorist?) “Jet Formation in QCD”
Cambridge Workshop July 20, 2002 Rick Field - Florida/CDFPage 1 The “Underlying Event” in Hard Scattering Processes  What happens when a proton and an.
Simulating Physics at the LHC
Event Simulation at the LHC
The Generator Phase in Gauss
Overview of IPPP Monte Carlo Tools
New Developments in Herwig++
Peter Richardson IPPP, Durham University
Simulating New Physics at the LHC
Energy Dependence of the UE
Implications of First LHC Data: Underlying Event Measurements
Monte Carlo Simulations
MB&UE Working Group Meeting UE Lessons Learned & What’s Next
PHZ 6358 Fall 2011 The Modeling of the Underlying Event Rick Field
The “Underlying Event” in Run 2 (CDF)
MB&UE Working Group Meeting CMS UE Data and the New Tune Z1
Predicting MB & UE at the LHC
Toward an Understanding of Hadron-Hadron Collisions
Hard Core Protons soft-physics at hadron colliders
Predicting “Min-Bias” and the “Underlying Event” at the LHC
Early Physics Measurements University of Florida October 2009
Predicting “Min-Bias” and the “Underlying Event” at the LHC
“Min-Bias” and the “Underlying Event” at CDF
Monte-Carlo Generators for CMS
Rick Field – Florida/CDF/CMS
The Tevatron Connection
“Min-Bias” and the “Underlying Event” in Run 2 at CDF and the LHC
The LHC Physics Environment
RHIC & AGS Annual Users’ Meeting
CDF Run 2 Monte-Carlo Tunes
“Min-Bias” & “Underlying Event” at the Tevatron and the LHC
“Min-Bias” and the “Underlying Event”
The Underlying Event in Hard Scattering Processes
PYTHIA 6.2 “Tunes” for Run II
Workshop on Early Physics Opportunities at the LHC
b-Quark Production at the Tevatron
Rick Field – Florida/CDF/CMS
Presentation transcript:

Monte Carlo event generators for LHC physics Mike Seymour University of Manchester CERN Academic Training Lectures July 7th – 11th 2003 http://seymour.home.cern.ch/seymour/slides/CERNlectures.html

Monte Carlo for the LHC Basic principles Parton showers Hadronization Monte Carlo programs in practice Questions and answers MC for LHC 4

Monte Carlo Programs in Practice HERWIG Status and Structure Example input, control parameters Example output Physics examples PYTHIA The Future – Object Oriented Event Generators ThePEG and PYTHIA7 HERWIG++ SHERPA With thanks to Torbjörn Sjöstrand, Stefan Gieseke, Frank Krauss and Peter Richardson MC for LHC 4

HERWIG Current status: Version 6.500 released on October 16th 2002 http://hepwww.rl.ac.uk/theory/seymour/herwig/ ~ 60,000 lines of FORTRAN, 11 authors (6 currently active) “The last FORTRAN version”? Recent new features: Les Houches accord interface for arbitrary hard processes Spin correlation algorithm Additional SM, MSSM and other BSM processes Interface to MC@NLO program (Frixione & Webber) Forthcoming features: (!) CKKW-like multijet matrix element matching Multiple hard and soft interaction underlying event model (Jimmy+Ivan)  see later MC for LHC 4

Structure HWIGPR: main program HERWIG: subroutine library Supplied, but needs modifying to initialize parameters, steer event generation, etc HERWIG: subroutine library Shouldn’t need modifying! HWABEG: analysis initialization User supplied HWANAL: event analysis HWAEND: terminate analysis MC for LHC 4

Read in SUSY parameters Example Main Program Process code: see list Phase space cuts: process dependent Read in SUSY parameters (from ISAWIG) MC for LHC 4

Processes Available MC for LHC 4

Production/Decay Spin Correlations eg top quark pairs in e+e- annihilation: Full spin correlations included, by factorized, step-by-step algorithm MC for LHC 4

Production/Decay Spin Correlations eg top quark pairs in e+e- annihilation: Correlation between lepton and beam lepton and top MC for LHC 4

PYTHIA Current status: Version 6.218 released on June 30th 2003 http://www.thep.lu.se/~torbjorn/Pythia.html ~ 60,000 lines of FORTRAN Recent new features: Les Houches accord interface for arbitrary hard processes Baryon-number violating decays in R-parity violation Mass effects in gluon emission ( != dead cone ) Additional SM, MSSM and other BSM processes Forthcoming features: New multiple interaction model  see later MC for LHC 4

MC for LHC 4

MC for LHC 4

MC for LHC 4

MC for LHC 4

MC for LHC 4

MC for LHC 4

MC for LHC 4

MC for LHC 4

Mass Effects in PYTHIA Dead cone only exact for – emission from spin-0 particle, or – infinitely soft emitted gluon In general, depends on – energy of gluon – colours and spins of emitting particle and colour partner  process-dependent mass corrections MC for LHC 4

Tuning PYTHIA to the Underlying Event Rick Field (CDF): keep all parameters that can be fixed by LEP or HERA at their default values. What’s left? Underlying event. Big uncertainties… http://www.phys.ufl.edu/~rfield/cdf/chgjet/chgjet_intro.html MC for LHC 4

Multiple-Parton Scattering off 1 Multiple-Parton Scattering on Parameter Value Description MSTP(81) Multiple-Parton Scattering off 1 Multiple-Parton Scattering on MSTP(82) Multiple interactions assuming the same probability, with an abrupt cut-off PTmin=PARP(81) 3 Multiple interactions assuming a varying impact parameter and a hadronic matter overlap consistent with a single Gaussian matter distribution, with a smooth turn-off PT0=PARP(82) 4 Multiple interactions assuming a varying impact parameter and a hadronic matter overlap consistent with a double Gaussian matter distribution (governed by PARP(83) and PARP(84)), with a smooth turn-off PT0=PARP(82) Parameter PYTHIA 6.115 PYTHIA 6.125 MSTP(81) 1 MSTP(82) PARP(81) 1.4 GeV/c 1.9 GeV/c PARP(82) 1.55 GeV/c 2.1 GeV/c PARP(83) 0.5 PARP(84) 0.2 MC for LHC 4

Beware, multiple interaction parameters strongly correlated with parton distribution functions… MC for LHC 4

MC for LHC 4

Conclusion: can fit these data but in many different ways  Large uncertainty in high energy extrapolation Also able to fit b production cross section… MC for LHC 4

Object Oriented Event Generators ThePEG: Toolkit for High Energy Physics Event Generation PYTHIA7: Implementation of physics of PYTHIA6 plus some improvements HERWIG++: Physics improvements from HERWIG plus backward compatibility SHERPA: completely new event generator MC for LHC 4

MC for LHC 4

MC for LHC 4

MC for LHC 4

MC for LHC 4

MC for LHC 4

MC for LHC 4

MC for LHC 4

MC for LHC 4

MC for LHC 4

MC for LHC 4

Conclusions Get to know your Monte Carlo! Remember what is fixed by LEP and HERA data Question what isn’t Tevatron data crucial testing ground The next generation is coming… Software improvements Physics improvements MC for LHC 4

Announcement How to write a 22 event generator Several members of BSM Monte Carlo working group expressed interest in a tutorial on How to write a 22 event generator and interface it through the Les Houches Accord Peter Richardson has agreed to give one ~ middle of next week Anyone interested email me and I will pass on to Peter… MC for LHC 4

Reminder – FAQs Lecture 5, Friday 11th July: Question and Answer session Email questions to: M.H.Seymour@rl.ac.uk Cutoff: Thursday 10th July, 2pm http://seymour.home.cern.ch/seymour/slides/CERNlectures.html MC for LHC 4