Ep protection at high energy against crazy tracks .. RECO part

[rafaellopesdesa]

Similar to #13279 , but also in reco part (the reason I am submitting as a different PR is that some of the analysis PR have been already merged).

The W' group reported that the electron Ep combination was returning unphysical values at high energies when the track pT was consistent with 0. We added a protection in the combination code to only use the Ep combination MVA at high energies when the track pT error is smaller than 10 times the track pT. It is a pretty safe cut that removes these badly measured tracks from the determination of the electron energy.

Reference: https://hypernews.cern.ch/HyperNews/CMS/get/physTools/3446/1/1/1/1.html

att: @fcouderc @matteosan1

[cmsbuild]

A new Pull Request was created by @rafaellopesdesa (Rafael Lopes de Sa) for CMSSW_8_0_X.

It involves the following packages:

RecoEgamma/EgammaTools

@cmsbuild, @cvuosalo, @davidlange6, @slava77 can you please review it and eventually sign? Thanks.
@Sam-Harper, @lgray this is something you requested to watch as well.
@slava77, @Degano, @smuzaffar you are the release manager for this.

cms-bot commands are list here #13028

[slava77]

@cmsbuild please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/11249/console

[cmsbuild]

+1
Tested at: 975aaad
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-13302/11249/summary.html

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-13302/11249/summary.html

[slava77]

+1

for #13302 975aaad

• changes in the code are in line with the description; the reco electrons energy is protected from large/bad inputs.
• jenkins tests pass and comparisons with baseline show no differences (the phase space of the fix is rather small)
• local tests (in CMSSW_8_0_X_2016-02-11-1100) show some differences in larger samples, mainly at high-pt for electrons and the downstream objects (pf electrons, jets, MET).

Here are some simple examples from 1316 (1 TeV electron gun with run2 setup)
pf electron pt is peaking slightly better at 1 TeV

the tails at high values are much smaller in general

and the reconstructed momentum is better for the showering electrons more noticeably than for other electrons

MET is smaller on average

and MET sumEt doesn't have an extra bump

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_8_0_X IBs (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @slava77, @davidlange6, @Degano, @smuzaffar

[davidlange6]

+1