Table of Contents

• General
• Madgraph
• Gridpack?
• Reweight?
• Anomalous Gauge Coupling model
• Merge LHE file
• others

General

• Total number of events is the “sum of genWeights”, in case of weighted samples (like madgraph, which have positive and negative weights) or sum of processed events in the other cases.
• weight cross section weight, scaled for 1/fb. It uses the xsec value in the tree, and it is computed as xsec[fb] * genWeight / sum(genWeights)

Madgraph

1. Model link: https://cms-project-generators.web.cern.ch/cms-project-generators/
2. Twiki: https://twiki.cern.ch/twiki/bin/view/Main/GenerationOfLheUsingMadgraph
3. Official archive of madgraph tutorials: https://cp3.irmp.ucl.ac.be/projects/madgraph/wiki/MGTutorial
4. FxFx Merging with madgraph: http://amcatnlo.web.cern.ch/amcatnlo/FxFx_merging.htm
5. The Higgs Characterisation model: http://feynrules.irmp.ucl.ac.be/wiki/HiggsCharacterisation#no1

Gridpack?

Ref: https://cp3.irmp.ucl.ac.be/projects/madgraph/wiki/IntroGrid

Reweight?

Ref: https://cp3.irmp.ucl.ac.be/projects/madgraph/wiki/Reweight

Anomalous Gauge Coupling model

Ref: http://feynrules.irmp.ucl.ac.be/wiki/AnomalousGaugeCoupling

Merge LHE file

Reference: https://twiki.cern.ch/twiki/bin/view/CMSPublic/SWGuideSubgroupMC#1_2_Using_pLHE_campaigns

Link of c++ code:

• https://twiki.cern.ch/twiki/pub/CMSPublic/SWGuideSubgroupMC/mergeLheFiles.cpp or,
• https://github.com/cms-sw/genproductions/blob/8e1725388083b6fe25b84bf238950f73f932fcbb/bin/MadGraph5_aMCatNLO/cards/production/13TeV/WpWm_POL/WpWm_LL/mergeLheFiles.cpp

** Instruction for use:**

modify the following line defining the output merged file:

    std::ofstream outFile("/tmp/covarell/out.lhe", std::ios::out);

perform the following actions:

    g++ -Wall -o mergeLheFiles mergeLheFiles.cpp
    ls tempdir/*.lhe > laMiaLista
    ./mergeLheFiles laMiaLista

Now, we will get a single LHE file called out.lhe.

others

1. why we specify a minimum QCD and a maximum QED order in madgraph?

   Ref: https://answers.launchpad.net/mg5amcnlo/+question/234568

   • By default MadGraph takes the lowest order in QED, i.e. QED = 0
   • If we specify an order (QED/QCD) this is always a maximal value.
   • If we did not specify any order, then MadGraph chose the oder which has the less QED order by default since this is, in most of the cases, the most important contribution (i.e. the other contribution are below the theoretical/statistical error).