AnalysisTop: fixing bug in CalcTTZPartonHistory
The bug in TTZPartonHistory.cxx was reported in the JIRA ticket ANALYSISTO-1322.
The truthParticles container is necessary for calculating the ttZ parton history. In the past this container was retrieved from the xAOD. With the usage of DAOD_PHYS this container no longer exists but must be built from several Truth collections.
The relevant code from CalcTtbarPartonhistory.cxx (l.112-126) was adapted to perform this task in the TTZPartonHistory. Besides the TruthTop collection, two further collections are necessary.
- 'TruthBosonsWithDecayParticles' includes the on-shell Z if it exists.
- 'HardScatterParticles' adds the gg->ttZ vertex for off-shell Z reconstruction.