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Opened 3 years ago

Last modified 3 years ago

#792 new Bug

A bug on b-tagging in CMS Delphes card

Reported by: starlight37 Owned by:
Priority: critical Milestone:
Component: Delphes code Version: Delphes 3
Keywords: Cc:

Description

Dear Delphes team,

I recently found a bug on b-tagging in CMS Delphes card.

In a recent version of Delphes.3.3.0, b-tagging parameterisations to recent ATLAS and CMS publications is updated.

At b-tagging module on delphes_card_CMS.tcl says:

=============================

###########
# b-tagging
###########

module BTagging BTagging {

set JetInputArray? JetEnergyScale?/jets

set BitNumber? 0

# add EfficiencyFormula? {abs(PDG code)} {efficiency formula as a function of eta and pt}
# PDG code = the highest PDG code of a quark or gluon inside DeltaR cone around jet axis
# gluon's PDG code has the lowest priority

# based on arXiv:1211.4462

# default efficiency formula (misidentification rate)
add EfficiencyFormula? {0} {0.01+0.00038*pt}

# efficiency formula for c-jets (misidentification rate)
add EfficiencyFormula? {4} {0.25*tanh(0.018*pt)*(1/(1+ 0.0013*pt))}

# efficiency formula for b-jets
add EfficiencyFormula? {5} {0.85*tanh(0.0025*pt)*(25.0/(1+0.063*pt))}

}

=============================

I compared these efficiency formula with results of CSVM tagger on arXiv:1211.4462.

b-tagging efficiency and c-jet misidentification rate fit the result well. However, light jet misidentification rate is overestimated and it even reaches ~30% at jet PT ~ 500 GeV

If I use a formula 0.01+0.000038*pt , it seems the equation fits the result well.

Is this a bug?

Best wishes,
Sung Hak Lim

Attachments (2)

CMS_CSVM_tagger_Delphes.png (70.3 KB) - added by starlight37 3 years ago.
CMS b-jet tagging efficiency on Delphes card overlaied with CSVM tagger result on arXiv:1211.4462
CMS_CSVM_tagger_Delphes_modified.png (69.2 KB) - added by starlight37 3 years ago.
Modified CMS b-jet tagging efficiency on Delphes card overlaied with CSVM tagger result on ​arXiv:1211.4462

Download all attachments as: .zip

Change History (5)

Changed 3 years ago by starlight37

CMS b-jet tagging efficiency on Delphes card overlaied with CSVM tagger result on arXiv:1211.4462

Changed 3 years ago by starlight37

Modified CMS b-jet tagging efficiency on Delphes card overlaied with CSVM tagger result on ​arXiv:1211.4462

comment:1 follow-up: Changed 3 years ago by mselvaggi

Dear Sung,

it seems you are correct, thanks a lot for spotting this.
It has now been corrected in the repository version.
We'll make a new release very soon.

Thanks,
Michele

comment:2 in reply to: ↑ 1 Changed 3 years ago by starlight37

Dear Michele,

Thanks for fast reply. I saw the repository is updated.

Okay, then I'll use the repository version until new release appears.

I'm looking forward to see a next release!

Best wishes,
Sung

Replying to mselvaggi:

Dear Sung,

it seems you are correct, thanks a lot for spotting this.
It has now been corrected in the repository version.
We'll make a new release very soon.

Thanks,
Michele

comment:3 Changed 3 years ago by mselvaggi

Version 3.3.1 was just released.

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