Format for Jet.BTag?

[Si Xie]

Hi,

We have noticed that the Jet.BTag variable does not just take values 0 and 1, but seems to go up to 3. It suggests that you are saving two bits in this variable instead of a boolean. However I couldn't find any documentation on the meaning of the values. Can you please clarify?

The code documents the following only:
BTag 0 or 1 for a jet that has been tagged as containing a heavy quark

See for example this output file with HH->bbgammagamma events:

/afs/cern.ch/work/s/sixie/public/releases/analysis/CMSSW_5_3_9_patch3/src/Delphes-3.0.10/Delphes.hhbbgg.test.root

Thanks.
Si

[Si Xie]

I'm using Delphes-3.0.10

[Michele Selvaggi]

Hi,

it is saving the number of bits you specifiy in the config card. In your case if it goes up to 3 it means you probably have two btagging algos being tested.

Please check here for documentation:
https://cp3.irmp.ucl.ac.be/projects/delphes/wiki/WorkBook/Modules

Michele

[Si Xie]

Hi Michele,

OK I see these definitions now.
Thanks for the information.

You may want to update the comments in the DelphesClasses.h code so that it is more clear for users.
I assume the same thing is also true for tau tag?

Thanks.
Si

[Michele Selvaggi]

Hi Si,

we will update the information in the code.
There is the possibility to store bits for different tau algorithms in the jet class, but the TauTagging module does not perform this by default.
If you need this feature we can easily add this in the next release.

Michele