Opened 8 years ago
Last modified 8 years ago
#989 new Bug
Questions about b-tagging and EFlow
| Reported by: | Hareesh Menon | Owned by: | |
|---|---|---|---|
| Priority: | minor | Milestone: | |
| Component: | Delphes code | Version: | Delphes 3 |
| Keywords: | Cc: |
Description
Hi,
I'm simulating ttH and ttjets and I had a question about the particle flow algorithm. Are electrons and muons stored in Eflow or only in the Electron and Muon variables?
I was also wondering whether it is possible to get a b-tag probability rather than just a 0 or 1 value for a btag.
Thanks
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Yes, electrons and muons are stored also in EflowTracks. You can identify then via PID.
If you are using the provided ATLAS or CMS cards, the btagging is done via a parameterisation, i.e. we take efficiencies from the experimental public results but no proper btag discriminator is computed. If you need that you'll have to use something like the impact parameter significance of the 2nd or 3rd track or implement MVA discriminator yourself using such observables.
Some b-tag related observables are constructed and used in this module:
https://github.com/delphes/delphes/blob/master/modules/TrackCountingBTagging.cc
and used in this old card.
https://github.com/delphes/delphes/blob/3.3.0/cards/delphes_card_ILD.tcl
If you want to store those observables and attach them the jet, you'll have to add those in the Jet class and tell the TreeWriter to store them.
You can find instructions on how to do that here, especially part IV:
https://cp3.irmp.ucl.ac.be/projects/delphes/wiki/WorkBook/TutorialBologna