[IOMC]: update vertex smearing parameters for realistic 13 TeV 50ns collisions

[sarafiorendi]

back-porting of
#10384

[cmsbuild]

A new Pull Request was created by @sarafiorendi for CMSSW_7_1_X.

[IOMC]: update vertex smearing parameters for realistic 13 TeV 50ns collisions

It involves the following packages:

IOMC/EventVertexGenerators

@cmsbuild, @civanch, @mdhildreth can you please review it and eventually sign? Thanks.
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[davidlange6]

@sarafiorendi - apologies - perhaps I've missed it - is this new (3rd..) change to this beamspot discussed somewhere? We don't want these to change once we start using them.

[sarafiorendi]

Hi @davidlange6,

the reconstruction of the story is as follows:

1st change (#10048 et al.) was the first attempt to provide realistic vtx smearing parameters. These were computed from 0T runs.

2nd change (#10221) this is just a patch to the numbers in the previous round of PRs, which we found out were faulty
==> a bunch of MC were produced with these conditions

3rd change, the present one, computed on 3.8T runs. This differs from the previous version for the X position of the centroid and for the inclusion of the latest greatest PIX alignment. We observed that, with B = 3.8T, the X moved by ~200 um and this movement is large enough to be accounted for.
==> meant to be the best configuration for the coming MC production

I think @mmusich and @diguida can comment further

[mmusich]

@davidlange6 hopefully that should be the last time we change them. They should be used for the production of the new round of MC with the more realistic luminous region description (compared to data).
If you wish we can arrange to have it discussed at one of the AlCa meetings, but I believe you can find a pretty detailed description in the beamspot HN.
Another useful link is this page: Beasmpot Operations

[civanch]

please test

[cmsbuild]

The tests are being triggered in jenkins.

[cmsbuild]

+1
Tested at: 0717d60
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-10387/191099/summary.html

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_1_X IBs once checked with relvals in the development release cycle of CMSSW (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @Degano, @smuzaffar

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-10387/191099/summary.html

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_1_X IBs once checked with relvals in the development release cycle of CMSSW (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @Degano, @smuzaffar

[davidlange6]

+1