[12.5.X] Option to make track covariance Pos-def in packedcandidate

[mmusich]

PR description:

As reported in BPH https://indico.cern.ch/event/1155820/contributions/4853223/ the packing scheme of the track covariance in MINIAOD introduces the possibility for the covariance matrix to not be positive-definite, with implications to vertex refitting.
The PR adds a new method to PackedCanidate responsible for returning a reference to a pseudoTrack with positive defined covariance matrix.

PR validation:

A simple analyser reading packed candidate was run retrieving the pseudoPosDefTrack to check that the determinant is getting positive.

If this PR is a backport please specify the original PR and why you need to backport that PR. If this PR will be backported please specify to which release cycle the backport is meant for:

Backport of #39599 for analysis of 2022 HI prompt data.

[mmusich]

type tracking

[cmsbuild]

A new Pull Request was created by @mmusich (Marco Musich) for CMSSW_12_5_X.

It involves the following packages:

• DataFormats/PatCandidates (xpog, reconstruction)

@cmsbuild, @mandrenguyen, @clacaputo, @swertz, @vlimant can you please review it and eventually sign? Thanks.
@gpetruc, @missirol, @gouskos, @rovere, @hatakeyamak this is something you requested to watch as well.
@perrotta, @dpiparo, @rappoccio you are the release manager for this.

cms-bot commands are listed here

• Backported from Option to make track covariance Pos-def in packedcandidate #39599

[mmusich]

backport of #39599

[mmusich]

@cmsbuild, please test

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-718e3e/30057/summary.html
COMMIT: 5c28160
CMSSW: CMSSW_12_5_X_2023-01-15-0000/el8_amd64_gcc10
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmssw/40555/30057/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• No significant changes to the logs found
• Reco comparison results: 6 differences found in the comparisons
• DQMHistoTests: Total files compared: 51
• DQMHistoTests: Total histograms compared: 3724047
• DQMHistoTests: Total failures: 8
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3724017
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 50 files compared)
• Checked 216 log files, 167 edm output root files, 51 DQM output files
• TriggerResults: no differences found

[clacaputo]

+reconstruction

• Backport of Option to make track covariance Pos-def in packedcandidate #39599
• code is consistent with the original PR

[mmusich]

@cms-sw/xpog-l2 do you have any objection to signing this PR and the other backports? They are useful for analysis purposes and as far as I can tell do not break any existing workflow.
Thanks.

[vlimant]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_12_5_X IBs (tests are also fine) and once validation in the development release cycle CMSSW_13_0_X is complete. This pull request will now be reviewed by the release team before it's merged. @perrotta, @dpiparo, @rappoccio (and backports should be raised in the release meeting by the corresponding L2)

[perrotta]

+1