Event generation

Our simulation framework supports HepMC3 and stdhep data formats for the input of signal events from Monte Carlo event generators. As an example we will use a Whizard event generator that is included in the software release.

Generating H -> bb sample in Whizard

A reference configuration file for generating a HepMC3 sample of mu+ mu- -> H + neutrinos -> bb + neutrinos process is available at mucoll-benchmarks/generation/signal/whizard/mumu_H_bb_3TeV.sin. During the generation process a number of compilation files are created for each subprocess, therefore it is better to run it in a separate folder, like this:

mkdir gen_Hbb && cd gen_Hbb
whizard ../mucoll-benchmarks/generation/signal/whizard/mumu_H_bb_3TeV.sin

This process can be time-consuming, therefore to speed up the process you can copy the pre-generated sample and use it in the next step:

cp /cvmfs/muoncollider.cern.ch/datasets/tutorial_20230705/gen_Hbb/mumu_H_bb_3TeV.hepmc ./

or if you don't have access to CVMFS:

wget https://nbartosi.web.cern.ch/tutorial_20230705/gen_Hbb/mumu_H_bb_3TeV.hepmc

Madgraph

Another popular event generator is Madgraph5_aMC@NLO. A complete tutorial on how to use it can be found in this presentation.

Particle gun

It is sometimes useful for performance studies to simulate events with single particles (muons, pions, electrons etc) with specific parameters. A dedicated Python script allows to generate an LCIO file with stable particles, represented by LCIO::MCParticle objects. For example to generate 100 events with 1 muon/event having p_T = 10 GeV and polar angle randomly distributed in the range [10deg, 170deg]:

python ../mucoll-benchmarks/generation/pgun/pgun_lcio.py -e 100 -p 1 --pdg -13 13 --pt 10 --theta 10 170 -- pgun_mu.slcio

NOTE: A complete list of supported PDG IDs is defined in the PDG_PROPS dictionary in file mucoll-benchmarks/generation/pgun/pdgs.py, which follow the Monte Carlo numbering scheme from Particle Data Group.