Introduction to MadGraph/MadEvent:

Transcription

1 Introduction to MadGraph/MadEvent: an informal tutorial Florian Bonnet INFN - Sezione di Padova January 21st 2011

2 What I will do Why using MadGraph/MadEvent (MG/ME) Getting familiar with the MG/ME environment One example from A to Z Introduction to model building What I will not do Discuss the physics inside the program Discuss technical details (compilers...)

3 Making discoveries at the LHC Finding excesses over the SM backgrounds need to be well measured from data need to be well described by MC Use the peculiar features of signals (mass distributions, kinematics, angular distributions...) to: Improve signal/background ratio Identify the quantum numbers of new particles

4 Making discoveries at the LHC Finding excesses over the SM backgrounds need to be well measured from data need to be well described by MC Use the peculiar features of signals (mass distributions, kinematics, angular distributions...) to: Improve signal/background ratio Identify the quantum numbers of new particles need to be well described by MC

5 Why MadGraph/MadEvent? Idea : a MC code for theorists to talk to experimentalists A huge amount of BSM models? Data

6 Why MadGraph/MadEvent? Idea : a MC code for theorists to talk to experimentalists A huge amount of BSM models? Data Lagrangian Detector simulation Automatized Feynman Rules Parton shower & hadronization Signal & Background Events (parton level)

7 Why MadGraph/MadEvent? Idea : a MC code for theorists to talk to experimentalists A huge amount of BSM models? Data Lagrangian PGS Detector simulation Automatized Feynman Rules PYHTIA Parton shower & hadronization Signal & Background Events (parton level) MadGraph MadEvent

8 MadGraph/MadEvent Two ways to run MG/ME: On-line web interface Install whole package on your computer Let s go to MG/ME directory!

9 MadGraph/MadEvent MG/ME directory: Core Basis of avalaible models PYTHIA & PGS Analysis Tool Plots Working Module

10 MadGraph/MadEvent Template directory: Inputs Storage of events Binaries Core

11 MadGraph/MadEvent Cards directory: proc_card.dat param_card.dat run_card.dat pythia_card.dat pgs_card.dat processes model parameters running parameters PYTHIA options Detector charateristics

12 MadGraph/MadEvent proc_card.dat param_card.dat run_card.dat pythia_card.dat pgs_card.dat MadGraph MadEvent PYTHIA PGS Feyn. diagrams Amplitudes Parton-level events Hadron-level events Detector-level events

13 Example Signal: pp > h > mu+ e- ve~ vm g g Background: pp > w+w- > mu+ e- ve~ vm/h

14 Example process ID proc_card.dat

15 Example proc_card.dat highest order in couplings

16 Example proc_card.dat model

17 Example proc_card.dat

18 Example./bin/newprocess gunzip madevent.tar.gz tar -xvf madevent.tar Source code for the processes

19 Example param_card.dat! parameters are not independant: USE A CALCULATOR Used by PYTHIA, Needed for any new particle, you can use BRIDGE theory/bridge/index.html

20 Example run_card.dat + PRIMARY CUTS

21 Example Calculating cross-sections: Generating events:./bin/survey./bin/refine./bin/generate_events XXX_unweighted_events.lhe XXX_pythia_events.lhe XXX_pgs_events.lhco

22 Example Analysis: MadAnalysis (simpler) or ROOT (more complete)

23 Example Analysis: MadAnalysis (simpler) ma_card.dat Define classes of particles using PDG code

24 Example Analysis: MadAnalysis (simpler) ma_card.dat Define cuts on events

25 Example Analysis: MadAnalysis (simpler) ma_card.dat Define plots

26 Example Analysis: MadAnalysis (simpler)./plot_events plots.top signal background

27 Particles Model = Interactions Couplings

28 MadGraph Particles particles.dat Model = Interactions interactions.dat Couplings couplings.f

29 Model directory: usrmod: old version usrmodfr: new version,

30 Model directory: usrmod: old version usrmodfr: new version, compatible with FeynRules (feynrules.phys.ulc.ac.be) Mathematica package FeynRules Lagrangian FeynRules particles.dat interactions.dat couplings.f Madgraph usrmodfr FeynRules model modify cards usrmodfr new model MadGraph

31 Copy sm_fr directory and rename it NewModel

32 python2.5../usrmod_fr/usrmod.py save

33 MadGraph Particles particles.dat Model = Interactions interactions.dat Couplings couplings.f

34 particles.dat name interactions.dat couplings.f

35 particles.dat Fermion, Scalar, Vector... interactions.dat couplings.f

36 particles.dat Type of line in Feynman diagram interactions.dat couplings.f

37 particles.dat Mass interactions.dat couplings.f

38 particles.dat Width interactions.dat couplings.f

39 particles.dat Color charge interactions.dat couplings.f

40 particles.dat Name in Feynman diagram interactions.dat couplings.f

41 particles.dat PDG code interactions.dat couplings.f

42 particles.dat Majorana particles non existing code interactions.dat couplings.f

43 particles.dat! order: see HELAS libraries Murayama et al., KEK-91-11, 1992 interactions.dat couplings.f

44 particles.dat name of coupling interactions.dat couplings.f

45 particles.dat type of coupling interactions.dat couplings.f

46 particles.dat interactions.dat couplings.f

47 python2.5../usrmod_fr/usrmod.py create

48 particles.dat interactions.dat couplings.f GWEN(1)*PL + GWEN(2)*PR

49 particles.dat interactions.dat couplings.f

50 particles.dat interactions.dat couplings.f internal param. input.inc intparam_definition.inc

51 particles.dat ident_card.dat param_card.dat external param. interactions.dat couplings.f internal param. input.inc intparam_definition.inc

52 make testprog./testprog

53 MadGraph Particles particles.dat Model = Interactions interactions.dat Couplings couplings.f internal param. input.inc intparam_definition.inc ident_card.dat param_card.dat external param.

54 FeynRules (feynrules.phys.ulc.ac.be)

55 Open and go into SM

56 Definition of model Output interface

57 SM.fr Indices Gauge Indices External Parameters Internal Parameters Gauge Groups Particles Lagrangian param_card.dat

58 SM.fr Indices Gauge Indices External Parameters Internal Parameters Gauge Groups Particles Lagrangian Internal parameters to write Lagrangian

59 SM.fr Indices Gauge Indices External Parameters Internal Parameters Gauge Groups Particles Lagrangian particles.dat

60 SM.fr Indices Gauge Indices External Parameters Internal Parameters Gauge Groups Particles Lagrangian couplings.f Let s do a new model!

61 TypeI.fr SM Type I

62 TypeI.fr SM Type I SM parameters SM parameters + Type I new parameters

63 TypeI.fr SM Type I

64 TypeI.fr SM Type I in the param_card.dat

65 TypeI.fr SM Type I Name of block in the param_card.dat

66 TypeI.fr SM Type I Default value

67 TypeI.fr SM Type I Ordering

68 TypeI.fr SM Type I

69 TypeI.fr SM Type I Intermediate parameters to help writing the Lagrangian Mathematica -> Matrices allowed

70 TypeI.fr SM Type I

71 TypeI.fr SM Type I Intermediate parameters to help writing the Lagrangian

72 TypeI.fr SM Type I

73 TypeI.fr SM Type I Kinetic terms Vector in flavor space

74 TypeI.fr SM Type I Kinetic terms Gamma Matrices

75 TypeI.fr SM Type I Kinetic terms Partial derivative

76 TypeI.fr SM Kinetic terms Type I Kinetic terms

77 TypeI.fr SM Gauge Interactions Type I Gauge Interactions

78 TypeI.fr SM Gauge Interactions Type I Gauge Interactions

79 TypeI.fr SM Yukawa Interactions Type I Yukawa Interactions

80 TypeI.nb

81 TypeI.nb TypeI

82 TypeI.nb

83 TypeI.nb TypeI.fr

84 TypeI.nb

85 MadGraph 5 FeynRules MadGraph4 MadEvent PYTHIA PGS MadGraph5

86 MadGraph 5 New features: New diagram generation (faster) New color structures Unlimited decay chains Compatible with PYTHIA 8 Automatic generation of HELAS routines UFO Universal FeynRules Output ALOHA Automatic Language-independent Output of Helicity Ampltudes self-contained Python code not tied to any matrix element generator Automatic generation of the necessary HELAS code for any new model Vertices with any Lorentz structure Effective vertices with any # particles

87 What I didn t have time to talk about ROOT (Tree & leaves, ExRootAnalysis etc) DELPHES (alternative to PGS) BRIDGE (Tool to calculte BR and width)

88 Summary User-friendly MC: from Lagrangian to events Every level of simulation: cross-sections, parton-level, hadronlevel, detector level Compatible with FeynRules MadGraph 5 very exciting for BSM phenomenology. If you have any question I m in office 313, otherwise: feynrules.phys.ulc.ab.be