Possibility to simulate the process

Asked by Maksym Ovchynnikov

Consider a model in which a scalar particle X may be produced by decays of Higgs bosons, h > X X, and later decays into a pair of quarks (u,d,s,c,b). I am interested in decay/hadronization products of these final states.


1) Assuming that the model is implemented in MadGraph, is it possible to generate such events using Madgraph (i.e., a run MadGraph+pythia8 in MadGraph)?
2) If yes, then, taking into account that the main Higgs production is through the gluon fusion (such that the addon hgg is needed), I will need to import both the hgg addon and the model of S. Is there any requirement for the implementation of the UFO model with this new scalar particle?
3) If yes, how to distinguish hadrons from the h production vertex from hadrons from the S decay products hadronization/decay events in the output (.lhe?) file?

I would be very grateful for your help.

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Olivier Mattelaer (olivier-mattelaer) said :


1) yes you can run pythia8 after MG5aMC generation. We provide an easy interface to run pythia8 directly but you can obviously also run pythia8 on your own using the lhe file as input.

2) If you generate the model from Feynrules or equivalent then I would suggest to add the effective operator for ggh directly at the FeynRules level rather than merging the model at the UFO level. But to answer your question. Otherwise i'm not an expert in model building to comment on that.

3) hadronization will occcur in pythia8 not in madgraph. So the output that you need to look at is the hepmc output and not lhe file.
Here also I'm not able to comment. HEPMC manual is likely the reference here to see which information is kept in the format.



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