new residualdecay

[mkirsano]

No description provided.

[cmsbuild]

A new Pull Request was created by @mkirsano for CMSSW_7_4_X.

new residualdecay

It involves the following packages:

GeneratorInterface/Pythia8Interface

@vciulli, @covarell, @thuer, @cmsbuild, @nclopezo, @bendavid can you please review it and eventually sign? Thanks.
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[mkirsano]

This should solve the problem of double counting and incorrect event structure in the cases when residual decays are cascade decays (this can happen for K0s). The idea is to test it and then propose to add the method used here to the pythia8 code.

[bendavid]

Is the HepMCA2.h file copied verbatim from pythia, or are there changes here specifically for the residualDecay use case?

How do we want to deal with configuring the residualDecays consistently with the main pythia8 instance as far as the decay length limits are concerned? Do we want to hardcode the defaults?
https://github.com/cms-sw/cmssw/blob/CMSSW_7_1_X/Configuration/Generator/python/Pythia8CommonSettings_cfi.py

[mkirsano]

I took HepMC.h from pythia8, removed some methods and added append_event. In principle the unneeded methods could be left there.

[bendavid]

No no, better to keep the duplication of code to a minimum.

[mkirsano]

It is of course easier to hardcode the parameters. But in principle I think they can be extracted at runtime from the main generator and put into the decayer.

[bendavid]

Ok, even better. I guess could even just automatically take only the lines starting with "ParticleDecays:"

[mkirsano]

I added what we discussed above. Plus some cleaning.

[cmsbuild]

Pull request #6938 was updated. @vciulli, @covarell, @thuer, @cmsbuild, @nclopezo, @bendavid can you please check and sign again.

[mkirsano]

pythia8 by default prints out the settings when initialized. The printout that I removed was a duplication.

[mkirsano]

I think the changes to MasterGen initialization are rather obvious: just remove the code duplication and add a message to distinguish between settings printout for it and for the Decayer. I tested this.

[bendavid]

Yes ok agreed. Sorry, getting paranoid these days.

[bendavid]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_4_X IBs unless changes or unless it breaks tests.

[cmsbuild]

+1
Tested at: 9eb8029
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-6938/1641/summary.html

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_4_X IBs unless changes (tests are also fine). This pull request will be automatically merged.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-6938/1641/summary.html