Does Delphes hadronize/decay/shower partons/particles?

[drakemarquis]

I am curious about what is really fed in Delphes. The purpose of this simulator is to simulate the detector. So we should feed the information (4 momenta, spins, etc.) of stable, colorless particles, right?

In Madgraph, you can install pythia-pgs and Delphes and play with it. I used Madgraph to simulate pp > ttbar and use pythia to do the showering. Then, I looked at the outputs. I simply looked at one .lhe file, and found that there are mostly quarks, gluons and ttbar. I did not find any stable, colorless particles. So I would guess Delphes does hadronization/decay/showering?

[Michele Selvaggi]

Hi,

the LHE file produced by MG contains only ME events. The showered ones are in *.hep format (or *.hepmc if you run at NLO)

Delphes can take as input both hadronized files (usually stdhep) or you can run the hadronization inside Delphes. The latter requires you to have your own Pythia8 installation, as explained here:

https://cp3.irmp.ucl.ac.be/projects/delphes/wiki/WorkBook (Running Delphes with Pythia8)

The "standard" way of running Delphes though is by feeding an stdhep file (or hepmc) and running the relevant executable

./DelphesSTDHEP cards/delphes_card_CMS.tcl delphes_output.root input.hep

./DelphesHepMC cards/delphes_card_CMS.tcl delphes_output.root input.hepmc

If you run Delphes within the MG chain, if everything has worked properly you should have a root file at the end

Cheers,
Michele

[drakemarquis]

Replying to mselvaggi:

Hi,

the LHE file produced by MG contains only ME events. The showered ones are in *.hep format (or *.hepmc if you run at NLO)

Delphes can take as input both hadronized files (usually stdhep) or you can run the hadronization inside Delphes. The latter requires you to have your own Pythia8 installation, as explained here:

https://cp3.irmp.ucl.ac.be/projects/delphes/wiki/WorkBook (Running Delphes with Pythia8)

The "standard" way of running Delphes though is by feeding an stdhep file (or hepmc) and running the relevant executable

./DelphesSTDHEP cards/delphes_card_CMS.tcl delphes_output.root input.hep

./DelphesHepMC cards/delphes_card_CMS.tcl delphes_output.root input.hepmc

If you run Delphes within the MG chain, if everything has worked properly you should have a root file at the end

Cheers,
Michele

Dear Michele,

Thanks for clarifying!

Cheers!

drakemarquis