tuning MVA cuts for lowPt and tobTec

[mhwalker]

Retuned LowPtTripletStep highPurity MVA cut to remove the step in the chi2 distribution - it pretty much disappears.

Retuned TobTecStep highPurity MVA cut to recover some efficiency at high dxy. Most efficiency lost for dxy < 50 cm recovered.

[mhwalker]

The problems can be seen here (high dxy efficiency loss): http://cmsdoc.cern.ch/cms/Physics/tracking/validation/MC/CMSSW_7_5_0_pre5/MCRUN2_75_V5_PU_highPurity_25ns/RelValTTbar/effvspos.pdf

(chi2 step):
http://cmsdoc.cern.ch/cms/Physics/tracking/validation/MC/CMSSW_7_5_0_pre5/MCRUN2_75_V4_PU_highPurity_50ns/RelValTTbar/tuning.pdf

[cmsbuild]

A new Pull Request was created by @mhwalker (Matthew Walker) for CMSSW_7_5_X.

tuning MVA cuts for lowPt and tobTec

It involves the following packages:

RecoTracker/IterativeTracking

@cmsbuild, @cvuosalo, @slava77 can you please review it and eventually sign? Thanks.
@ghellwig, @makortel, @GiacomoSguazzoni, @rovere, @VinInn, @mschrode, @istaslis, @gpetruc, @cerati, @dgulhan this is something you requested to watch as well.
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[VinInn]

Let's go with this, we can retune later...

[slava77]

@VinInn @rovere
I suppose we are giving up on vxy>50 cm, right?
(efficiency for vxy>50 cm look about the same in pre4.vs.pre5 comparisons as in pre4.vs.fixFromThisPR)

[slava77]

@cmsbuild please test
at least the change in the code looks next to trivial, nice.
There are no payloads changes, right?
@mhwalker please confirm

[mhwalker]

@slava77 Correct, no payload changes, only changing the cut value.

[cmsbuild]

The tests are being triggered in jenkins.

[cmsbuild]

+1
Tested at: bbfedcc
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-10086/6046/summary.html

[slava77]

+1

for #10086 bbfedcc

• tested in CMSSW_7_5_0_pre6 /test area sign569/ including higher stat tests (still not much to get a high precision picture)
• the efficiency in high purity tracks is slightly higher for tracks with larger displacement (in agreement with the plots from Matt)
• generalTracks distributions are almost unchanged (as expected: only high-purity assignment changes)
• in ttbar and dijet events there is also a fairly similar noticeable change in the number of higher level objects or other tracks:
  • ~5-10% increase in recoConversions (in gamma 35 sample it's even more significant: ~30% more single leg conversions in the barrel, and 10% more in the endcap)
  • ~0.5% increase in pf candidates
  • ~1.5% increase in electronGsfTracks

flat-pt dijet sample (400 events here)

the rest if the plots are with ttbar run1-like (pu~20; 200 events here, just higher stat test)
in line with the plot from Matt

[slava77]

(NB: my plots were in a comparison with 750pre6 [black])

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_5_X IBs once checked with relvals in the development release cycle of CMSSW (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @Degano, @smuzaffar

[davidlange6]

+1