wiki:MC4BSM2013

Installation instructions and pre-workshop exercises

Install on Windows

The different program are foreseen to run on Linux/Mac. If you don't have Linux or Mac, the best solution is to install Linux (I would advice to install Ubuntu) in dual boot and follow the instructions for Linux. This video might help you to do so: http://video.google.com/videoplay?docid=-2369893842637434537 virtual machine are fine, but quite often the library readline is not present on the system. This package is not mandatory but allozs mg5 to have history and nice auto-completions. So you might consider to install that library first and the compile python2.6.

Install on Linux

  • python 2.6/2.7
    MadGraph 5 requires python 2.6 or python 2.7. In order to check your version of python, you can type: python --version. Some of the repositories are still on python 2.5. So if updating python via your repository manager didn't work. you can download directly python from the following link: http://www.python.org/download/ and follow instructions.
  • Madgraph5
    You will find madgraph5 package on the following page: https://launchpad.net/madgraph5. For this program, you just need to untar it. To check if mg5 is correctly install you directly try to run it by doing: ./bin/mg5 If you don't have a valid python version. It will fail directly.
  • MadAnalysis
    This programs is not mandatory but allows to have partonic distributions done automatically. In order to install this program, you need to launch mg5 (./bin/mg5) and then type
       install MadAnalysis
    

Install on MacOs

  1. Basic program
  1. !MadGraph5
    • python
      1. The default python version of MacOs 10.6 is python 2.6 and is (in 99% of the case) fully working with Madgraph5, so nothing to install for you.
      2. The python version of MacOs 10.7 is python 2.7. And this one works perfectly, so nothing to install for you.
      3. For other version of MacOS, you will need to install python2.7 from the python web site: http://www.python.org/download/
    • Madgraph5
      You will find madgraph5 package on the following page: https://launchpad.net/madgraph5. For this program, you just need to untar it. To check if mg5 is correctly install you directly try to run it by doing: ./bin/mg5 If you don't have a valid python version. It will fail directly.
    • MadAnalysis
      This programs is not mandatory but allows to have partonic distributions done automatically. In order to install this program, you need to launch mg5 (./bin/mg5) and then type
         install MadAnalysis
      

Instructions for the tutorial exercise

  • If you haven't ran the tutorial before the lectures please do it now. Please launch mg5 ./bin/mg5 and type the following command:
       tutorial
    

and follow the tutorial instructions on the screen.

  • The exercice of this tutorial is to
    1. Use the model generatedby Feynrules
    2. generate $ p p \to U \bar U $
    3. generate some events
    4. pass the events to Pythia
    5. Restart the chain but this time by including all the decay chain in MG5.

Note that in order to have the correct cross-sections in the second cases or to have the correct branching ratio computed by Pythia in the first case, we need first to compute the width and the branching ratio of the non standard model particles.

  • The model
    The simple way to have access to a model in MG5 is to put in the directory: MG5_DIR/models after that you can simply import it in MG5 by doing
       import model MODELNAME
    
    or
       import model MODELNAME --modelname
    
    The option --modelname tells MG5 to use the name of the particles defines in the UFO model, and not the usual MG5 conventions for the particles of the SM and the MSSM. In principle this shouldn't change anything in the model that you load. The first time that you import a new model, it is a good moment to test it! For this
    1. You can run MG5 in debug mode (./bin/mg5 --debug)
    2. You can test the Lorentz invariance/Gauge invariance/... of at least a couple of processes.

Choose one model at the MG5_DIR/models directory and try it:

   import model MODELNAME
   check p p > a a 

  • Generation of events (Decay done in MG5) Add the decay in MG5 (such that the full spin correlation is taken into-account) and generate events. In order to learn the syntax of the decay chain. Please type
        help generate
    

Playing with the Higgs Characterization model

  • The model

Get familiarised with the model, check the particles available to play the role of a resonance and their interactions.

   import model HiggsCharact_UFO
   display particles
   display interactions X

Download the UFO model for the Higgs characterization here: https://feynrules.irmp.ucl.ac.be/wiki/HiggsCharacterization

  • Parton-level event generation

1) Try to generate events for different spin/parity options for di-photon final state. What is the diference between

   generate p p > X , X > a a

and

   generate p p > a a

Check the diagrams.

2) Generate events for a resonance with different parity but same spin (e.g. spin0+, spin0-). Choose parameters properly.

  • MLM matching

Use the matching scheme within MG5 for p p > x2 + 0,1,2-jets @ 14TeV. Choose the run parameters carefully, and check your DJR plots. Is the matching working properly? Vary your cutoff scale and check that the cross section does not change significantly. For this, you should have MadAnalysis and pythia installed within the MG5 interface. To instal simply:

   install MadAnalysis
   install pythia-pgs
Last modified 6 years ago Last modified on 04/19/13 09:25:10