Mitigation action for fakerate at high PU - HighPurity only

[ebrondol]

Some cuts in the triplets iterations have been applied in order to mitigate the fakerate in the HighPurity tracks collection keeping high the efficiency - even if it is getting a bit worse. This is not a definitive solution, of course.
I have presented the problem in the UPSG meeting.
Here reported the effect on the fakes for PU200: in red the fakes for 900pre2, in blue 819pre12 and in black 900pre2+PR.

It should not affect timing significantly.

[cmsbuild]

A new Pull Request was created by @ebrondol for CMSSW_9_0_X.

It involves the following packages:

RecoTracker/IterativeTracking

@cmsbuild, @cvuosalo, @slava77, @davidlange6 can you please review it and eventually sign? Thanks.
@ghellwig, @makortel, @felicepantaleo, @GiacomoSguazzoni, @rovere, @VinInn, @mschrode, @gpetruc, @dgulhan this is something you requested to watch as well.
@davidlange6, @smuzaffar you are the release manager for this.

cms-bot commands are listed here #13028

[makortel]

@cmsbuild, please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/17768/console Started: 2017/02/13 20:43

[cmsbuild]

+1
Tested at: 4281d3e
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-17504/17768/summary.html

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-17504/17768/summary.html

[VinInn]

Should not this be on top of #17228 ?

[ebrondol]

@VinInn it is indipendent from the PR #17228

[slava77]

On 2/14/17 1:25 AM, ebrondol wrote: @VinInn <https://github.com/VinInn> it is indipendent from the PR #17228 <#17228>

I suppose, the point is to evaluate this PR performance in combination with #17228 and if the combined looks OK to accept both.

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[ebrondol]

@slava77 yes, please.

[slava77]

some plots from PU200

with just this PR:

• ~4.5% reduction in charged hadrons (mostly pt<1 GeV) is the most visible change in higher level objects [track MTV and other indications point that these are mostly fakes]
  

compare this to the total generalTracks with fairly small changes

.. there are fewer shorter tracks

This is the same for 17504+17228

[slava77]

MTV fake rate for generalTracks looks only moderately better for pt>0.9 [this is a combination of 17504 and 17228]

inclusively, it looks a bit better, but the pt>0.9 is probably more important

[slava77]

Here is a set of other specialized MTV plots in combination with 17228:

this is apparently matching also what goes to PF candidates, looks good

@makortel is the BtvLike selection actually correct? @arizzi @ferencek don't we use the PFCandidates by default now? So, I would expect the BtvLike to actually look more like the Pt09Hp plot below.

If the issue in BtvLike is somewhat bogus, then we may be able to advance with this and 17228 PRs

[slava77]

Some plots for this PR alone, since it appears to be good to go be more ready to go by itself

the FR improvement in BtvLike looks good

There is a small efficiency loss in HP around eta~1. Are we OK with this?

[ebrondol]

@slava77 we are awae of the loss of efficiency, but it seems a price to pay for now.

[slava77]

On 2/16/17 6:44 AM, ebrondol wrote: @slava77 <https://github.com/slava77> we are awae of the loss of efficiency, but it seems a price to pay for now.

OK I'll sign this shortly. For the 17228, I will need feedback on the notes in #17504 (comment)

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[slava77]

+1

for #17504 4281d3e

• updated high purity selections for HighPtTriplet and LowPtTriplet Step in phase2
• jenkins tests pass and comparisons with baseline show differences in 2023 workflows, (the stats are low, but differences are consistent with the change made and the plots posted in the PR descrition and local tests)
• local tests with PU200 show roughly expected behavior, most visible in plots using tracks with high purity selection; Btag ROCs look good (below)
  • technical performance changes are minor (the reco time totals are within 0.5%)

Here are a couple of BTV plots with this PR alone


These look pretty good

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_9_0_X IBs (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @smuzaffar

[davidlange6]

+1

[slava77]

Looking at 17504+17228

in PU200
(compare, e.g. https://cloud.githubusercontent.com/assets/4676718/22228971/9096d960-e189-11e6-9296-d817e246d18f.png)
the B-tagging performance is still better than the current baseline

So, I conclude that the MTV "BtvLike" plots are not really corresponding to the current default Btagging objects