To save SimTracks with particle code (PDG code) from a list, need

to activate the watcher SaveSimTrack specifying the codes in .cfg file:

process.g4SimHits.Watchers = cms.VPSet(cms.PSet(

SaveSimTrack = cms.PSet(

PDGCodes = cms.untracked.vint32([2212])

),

type = cms.string('SaveSimTrack')

) )

will save all particles of code 2212.