Figure out the electron isolation issue

[andreypz]

Photons are not removed from pf-Isolation as Nate found out.

[andreypz]

Looks like the problem is known and described on official egamma page: https://twiki.cern.ch/twiki/bin/view/CMS/EgammaPFBasedIsolation#Recommended_electron_vetoes_Upda They don't seem to provide a concrete code though. Although it looks like it is implemented in the PFIsolationEstimator class that we are using (see EgammaAnalysis/ElectronTools/src/PFIsolationEstimator.cc in your files and look for isPhotonParticleVetoed() function) but is seems to have been done by a noob (like Brain or even worse), so there might be bugs.

Other related codes:

• an example of that photon removal in a different plugin: http://cmslxr.fnal.gov/lxr/source/CommonTools/ParticleFlow/plugins/PFCandWithSuperClusterExtractor.cc?v=CMSSW_5_3_13#086
• another alternative (which I think we used before): https://twiki.cern.ch/twiki/bin/view/CMS/PfIsolation (however it's not clear about the issue of photon removal here)

Why aren't we using any of those two? Where is PFIsolationEstimator.cc recommended?

[pollackscience]

For the mean time, this is as fixed as it can be without EGamma coming in and doing it correctly. We will have 3 versions (PFIsolationEstimator, CommonTools/ParticleFlow, SCFP Remover)

[pollackscience]

EGamma POG is aware of this issue, may have to do with PAT cleaning of pfobjects, no idea on when this will be fixed