[14_0_X] Pythia8 photon flux

[stahlleiton]

PR description:

backport of #43840

PR validation:

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:

[cmsbuild]

A new Pull Request was created by @stahlleiton for CMSSW_14_0_X.

It involves the following packages:

• GeneratorInterface/Pythia8Interface (generators)

@alberto-sanchez, @mkirsano, @SiewYan, @bbilin, @menglu21, @GurpreetSinghChahal, @cmsbuild can you please review it and eventually sign? Thanks.
@alberto-sanchez, @mkirsano this is something you requested to watch as well.
@sextonkennedy, @rappoccio, @antoniovilela you are the release manager for this.

cms-bot commands are listed here

[cmsbuild]

cms-bot internal usage

[stahlleiton]

@hjbossi

[menglu21]

@cmsbuild please test

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-4173a3/37854/summary.html
COMMIT: 4c0f63c
CMSSW: CMSSW_14_0_X_2024-03-01-1100/el8_amd64_gcc12
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmssw/44259/37854/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• You potentially removed 139 lines from the logs
• Reco comparison results: 67 differences found in the comparisons
• DQMHistoTests: Total files compared: 49
• DQMHistoTests: Total histograms compared: 3338820
• DQMHistoTests: Total failures: 1358
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3337440
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 48 files compared)
• Checked 205 log files, 166 edm output root files, 49 DQM output files
• TriggerResults: no differences found

[menglu21]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_14_0_X IBs (tests are also fine) and once validation in the development release cycle CMSSW_14_1_X is complete. This pull request will now be reviewed by the release team before it's merged. @sextonkennedy, @rappoccio, @antoniovilela (and backports should be raised in the release meeting by the corresponding L2)

[rappoccio]

+1