B-tagging problem

[Sergei Chekanov]

It was observed that b-tagging in Delphes 3.3 has very low efficiency (about ~3%).
Can you please check what is wrong? Here is an example

​http://mc.hep.anl.gov/asc/hepsim/events/pp/100tev/higgs_bbar_pythia8/rfast002/tev100_pythia8_higgs_bbar_00001.root

(Higgs to bbar sample)

The delphes card is:

​http://mc.hep.anl.gov/asc/hepsim/events/pp/100tev/higgs_bbar_pythia8/rfast002/info.txt

This problem was observed, by Jahred Adelman, for 13 TeV pp and Delphes 3.2 using this card:

​http://mc.hep.anl.gov/asc/hepsim/events/pp/13tev/pythia8_zbbar/rfast001/info.txt

(similar to the Snowmass card). We looked at the Jet.BTag variable to check b-tagging.
We expect at least 60% efficiency

Is it possible that enabling "JetAlgorithm 7" for jet substructure kills b-tag?

best, Sergei

[Michele Selvaggi]

Hi Sergei,

since 3.3.0 you have to call the JetFlavorAssociation module before btagging. I have attached a modified version of the card that should fix it.

Cheers,
Michele

[Sergei Chekanov]

Thanks, Michele

I've made "rfast003" tag in

​http://atlaswww.hep.anl.gov/hepsim/info.php?item=79

that includes this change. It looks like we are getting a higher rate of b-tagged jets. Jahred, can you check? Then I'll process 13 TeV samples.