[14_1_X Phase2 SIM] Fixed Birks saturation constants for HGCal scintillators

[civanch]

PR description:

The value of the main Birks saturation coefficient is taken from classical publications (NIM 80 (1970) 239-244), in which a biased value of the main term was proposed. It was fixed before Run2 for Hcal and now is fixed for HGCScintSD.

Regression for Phase-2 WFs is not expected.

PR validation:

private

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: likely NO

[cmsbuild]

cms-bot internal usage

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-44611/39800

• This PR adds an extra 32KB to repository

[cmsbuild]

A new Pull Request was created by @civanch for master.

It involves the following packages:

• SimG4CMS/Calo (simulation)
• SimG4Core/Application (simulation)

@mdhildreth, @civanch, @cmsbuild can you please review it and eventually sign? Thanks.
@fabiocos, @bsunanda, @makortel, @rovere, @ReyerBand, @slomeo, @felicepantaleo, @thomreis, @wang0jin this is something you requested to watch as well.
@rappoccio, @sextonkennedy, @antoniovilela you are the release manager for this.

cms-bot commands are listed here

[civanch]

please test

[civanch]

assign upgrade

[cmsbuild]

New categories assigned: upgrade

@srimanob,@subirsarkar you have been requested to review this Pull request/Issue and eventually sign? Thanks

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-194b19/38598/summary.html
COMMIT: 5700322
CMSSW: CMSSW_14_1_X_2024-04-04-1100/el8_amd64_gcc12
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week1/cms-sw/cmssw/44611/38598/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• You potentially added 15 lines to the logs
• Reco comparison results: 923 differences found in the comparisons
• DQMHistoTests: Total files compared: 48
• DQMHistoTests: Total histograms compared: 3307717
• DQMHistoTests: Total failures: 6892
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3300805
• DQMHistoTests: Total skipped: 20
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 47 files compared)
• Checked 202 log files, 165 edm output root files, 48 DQM output files
• TriggerResults: no differences found

[civanch]

+1

results should be affected, because scintillation hits are slightly different

[srimanob]

Hi @civanch

Thanks for the fix. When you said that result should be effected, do you think the fix should be backport for 14_0 production? Do we have validation outside this PR? FYI @cms-sw/hgcal-dpg-l2 @SohamBhattacharya @rovere

[civanch]

@srimanob , @cms-sw/hgcal-dpg-l2 @SohamBhattacharya @rovere, this fix provides a small effect on HGCal hits/digi and I would expect change <~1% of jet energy. In HCal similar fix changed visible energy for hadrons for ~1-2% and improved MC/data agreement on % level. In HCal scintillator is the main sensitive detector, in HGCal it is not the case.

So, we are speaking on a minor thing. In that case, I would prefer to have theoretically more correct variant, also it is safe to backport.

[srimanob]

Hi @civanch
Thanks for explanation. If it is very minor, I would propose to have it in master only. So we can validate it when the new pre-release comes. So, we keep production as is for the moment.

[srimanob]

+Upgrade

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next master IBs (tests are also fine). This pull request will now be reviewed by the release team before it's merged. @rappoccio, @antoniovilela, @sextonkennedy (and backports should be raised in the release meeting by the corresponding L2)

[civanch]

@srimanob , OK, agreed.

[pfs]

From the RecHit spectrum in the scintillator region one can see that indeed it has a very small impact
(e.g. here)
Thanks @civanch for this correction

[antoniovilela]

+1