Backport of "Fix for FastSim decays of exotic-descendent SM particles decaying outside pipe" to 10_2_X

[cericeci]

PR description:

Backport of #36122 and #36324 for preUL 2018 FastSim production. Full functionality of both, without the code formatting. Please check #36352 (backport to UL branch) first

This fixes a bug which would invalidate simulation for long-lived and a fraction of prompt signals (and luckily was introduced very recently, so most of the previous production is safe). Our understanding is that this case doesn't go against the no-change policy.

Original PR description: Jaebak found that some b- and d-mesons produced in the decays of exotic particles, which cross the beam pipe radius, have their decay performed twice, with sim hits created for each copy. This causes problems for some high-pT b-jets, as well as the MET in events that contain such jets. A few lines are added to ParticleManager.cc which results in FastSim deciding to not decay such particles further, and rather take only the original generator-determined decay trees. FastSim will still propagate these particles and create secondaries/material interactions, but it won't decay them.

If this PR is a backport please specify the original PR and why you need to backport that PR:

#36122 and #36324, needed for preUL 2018 MC production (most notably pMSSM scan)

[cmsbuild]

A new Pull Request was created by @cericeci (Carlos Erice) for CMSSW_10_2_X.

It involves the following packages:

• FastSimulation/SimplifiedGeometryPropagator (fastsim)

@ssekmen, @lveldere, @civanch, @mdhildreth, @cmsbuild, @sbein can you please review it and eventually sign? Thanks.
@matt-komm this is something you requested to watch as well.
@perrotta, @dpiparo, @qliphy you are the release manager for this.

cms-bot commands are listed here

[perrotta]

please test

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-b73311/20971/summary.html
COMMIT: aa8d90e
CMSSW: CMSSW_10_2_X_2021-11-28-0000/slc6_amd64_gcc700
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week1/cms-sw/cmssw/36353/20971/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: 2 differences found in the comparisons
• DQMHistoTests: Total files compared: 31
• DQMHistoTests: Total histograms compared: 3007546
• DQMHistoTests: Total failures: 1
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3007355
• DQMHistoTests: Total skipped: 190
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 30 files compared)
• Checked 129 log files, 28 edm output root files, 31 DQM output files
• TriggerResults: no differences found

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_10_2_X IBs (tests are also fine) and once validation in the development release cycle CMSSW_12_2_X is complete. This pull request will now be reviewed by the release team before it's merged. @perrotta, @dpiparo, @qliphy (and backports should be raised in the release meeting by the corresponding L2)

[perrotta]

-1
This PR is "fully signed", but it misses the necessary customization with the modifiers if it wants to be backported in a closed production release. In order not to merge it "by mistake" let have it orp-rejected by now. The flag will be overwritten if and when a modification will be implemented in the PR

[cmsbuild]

Pull request #36353 was updated. @perrotta, @ssekmen, @lveldere, @civanch, @mdhildreth, @cmsbuild, @sbein, @qliphy, @fabiocos, @davidlange6 can you please check and sign again.

[cericeci]

@perrotta I added the same modifier as in the 10_6 backport (and checked on CMSSW_10_2_X_2022-01-09-0000 that it activates properly). Would it be enough or should I add anything else? I'll do the same for #36354 , the 9_4 backport

[perrotta]

Could you please split this comment line, so that it can be more easily readable?

[cmsbuild]

Pull request #36353 was updated. @perrotta, @ssekmen, @lveldere, @civanch, @mdhildreth, @cmsbuild, @sbein, @qliphy, @fabiocos, @davidlange6 can you please check and sign again.

[perrotta]

please test

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-b73311/21608/summary.html
COMMIT: aa2c350
CMSSW: CMSSW_10_2_X_2022-01-09-0000/slc6_amd64_gcc700
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week1/cms-sw/cmssw/36353/21608/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: 0 differences found in the comparisons
• DQMHistoTests: Total files compared: 31
• DQMHistoTests: Total histograms compared: 3007546
• DQMHistoTests: Total failures: 1
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3007355
• DQMHistoTests: Total skipped: 190
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 30 files compared)
• Checked 129 log files, 28 edm output root files, 31 DQM output files
• TriggerResults: no differences found

[qliphy]

ping @cms-sw/fastsim-l2

[sbein]

+1

[perrotta]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_10_2_X IBs (tests are also fine) and once validation in the development release cycle CMSSW_12_3_X is complete. This pull request will be automatically merged.