Decay tables to pythia fails

Asked by Pablo on 2012-03-22


I created an mssm custom model
Just used a spectrum generator and calculated the param_card with the tool provided in the web.
Also I had to comment the line defining the model, cause it gave some error (modsel[1] should be 1)

The point is that when calling Pythia, Pythia is taking propperly the spectrum in the param card, but not the decays, so it changes ny custom model decays

How would I fixed?

Thak you

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Solved by:
Johan Alwall
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This question was originally filed as bug #961813.

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Johan Alwall (johan-alwall) said :

A better title for this question is: How to make Pythia use the decay tables from the SLHA file instead of calculating its own decays?

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Best Johan Alwall (johan-alwall) said :

Hello Pablo,

For MSSM, Pythia usually knows how to calculate branching ratios, and if it's allowed to use its own decay tables the decay kinematics are better treated (since it knows the interaction structure of the different decays). If your own branching ratios are used, Pythia will simply do isotropic decays. Having said that, it is easy to change the behavior: Either
1) avoid starting the model name with "mssm" (then branching ratios should be automatically read from the event file header)
2) Set IMSS(22)= 24 in the pythia_card.

All the best,

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Pablo (pablosp1988) said :

Thanks Johan Alwall, that solved my question.

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Pablo (pablosp1988) said :

Thank you very much for such a quick response
Mad graph is already running with my decays