Fix the wrong number of beam particles in SHERPA-MC in the HepMC3 branch.

Andrii Verbytskyirequested to merge
averbyts/athena:fix_sherpa into master

Fix the wrong number of beam particles in SHERPA-MC in the HepMC3 branch.

https://its.cern.ch/jira/browse/AGENE-2102

Tag @ewelina @jroggel

Edited by Andrii Verbytskyi

Merge request reports