pTRatioMax for charged tracks

[Archana]

Hello,

We are trying to implement the following CMS analysis with the delta phi variable given in 1305.2390. One of the cuts they require is "No isolated charged particle track with pT > 15 GeV, eta < 2.4". In addition, they also require a PTRatioMax for the charged tracks for be < 0.05 (explained on top to page 5 in the paper). The Delphes CMS card has a pTRatioMax for the electron and muon isolation. Is there an easy way to implement the same for charged tracks?

Thanks,
Archana

[Alexandre Mertens]

Hello,

Thanks for using the new Delphes version.

Yes, there are several ways to add an isolation on the charged tracks. A simple idea would be to

1) apply the “Merger” module to create the charged track collection (the TrackMerger/tracks collection does not contain the muons)
2) apply the “Isolation” module to check for isolation.
3) Add the isolated track in the Delphes output

As example:

1) the merger

####################
# Charged Track Merger
####################

module Merger ChargedTrackMerger {
# add InputArray InputArray
  add InputArray TrackMerger/tracks 
  add InputArray MuonMomentumSmearing/muons
  
  set OutputArray chargedtracks
}

2) the isolation

####################
# Charged Track Isolation
####################

module Isolation ChargedTrackIsolation {
  set CandidateInputArray ChargedTrackMerger/chargedtracks
  set IsolationInputArray EflowMerger/eflow  
  
  set OutputArray chargedtracks

  set DeltaRMax 0.5

  set PTMin 0.5

  set PTRatioMax 0.1
}

where you can enter the needed values.

3) In the TreeWriter module, the following line should be added:

add Branch ChargedTrackIsolation/chargedtracks ChargedTracks Track

It is also necessary to add the two new operations in the executionPath.
I hope this answer yours question, let us know if you have other comments/questions!

Cheers,

Alexandre

[Archana]

Thanks Alexandre, for the quick reply. We will implement your suggestion.