Move to Pythia 8 for cascade production

[olantwin]

No description provided.

[ThomasRuf]

The issue with this, one Pythia8 instance works for one process and ONE energy. For the cascade production, energies range over ~10 - 400 GeV. Creating a new instance and deleting for each energy/particle costs a huge CPU time penalty. Maybe one solution would be to round energies to 1 GeV, keep track of existing instances for each energy and particle, if not exist create new. If memory consumption allows.

[olantwin]

Thanks for this information. I'll try to discuss with the Pythia8 devs whether they can think of any other workarounds.