Susy gen fragment for trigger validation

[therwig]

This PR adds a fragment for the generation of production of EWK SUSY particles in association with ISR jets with Pythia. The process in includes pair production of neutralinos N2N1, N2C1, and C1C1 with small mass splitting mN2-mN1 = 2*(mC1-mN1) = 20 GeV, relevant for several SUSY MET+lepton cross triggers. Efficient population of the phase space relevant for these triggers is ensured with a HT>60 GeV requirement.

runTheMatrix tests ran successfully and produced the expected distributions.
This targets the Run3 Summer21 (12_0_X) MC production for TSG validation, e.g. p6 of
https://docs.google.com/presentation/d/1ED3idtHv8PqSRqHAf1RSDm64ZlqXaZysxAkBQ9vrheY/edit#slide=id.gec925d3f57_3_1

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-35203/25142

• This PR adds an extra 36KB to repository

[cmsbuild]

A new Pull Request was created by @therwig (Christian Herwig) for master.

It involves the following packages:

• Configuration/Generator (generators)

@SiewYan, @mkirsano, @Saptaparna, @cmsbuild, @GurpreetSinghChahal, @agrohsje, @alberto-sanchez can you please review it and eventually sign? Thanks.
@Martin-Grunewald, @fabiocos 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

[agrohsje]

please test

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-48393d/18444/summary.html
COMMIT: 2432e08
CMSSW: CMSSW_12_1_X_2021-09-08-2300/slc7_amd64_gcc900
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week1/cms-sw/cmssw/35203/18444/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: 4 differences found in the comparisons
• DQMHistoTests: Total files compared: 39
• DQMHistoTests: Total histograms compared: 3001001
• DQMHistoTests: Total failures: 6
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3000973
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 38 files compared)
• Checked 165 log files, 37 edm output root files, 39 DQM output files
• TriggerResults: no differences found

[agrohsje]

+generators

[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. @perrotta, @dpiparo, @qliphy (and backports should be raised in the release meeting by the corresponding L2)

[qliphy]

+1