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• (Example) Differences between event vertex, target and dump.
• (Example) Difference between truth quantity and reconstructed quantity.

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Unsorted Info

Kenichi and anyone write down some possibly-useful info here (rather than e-mail).  The info may be moved to a proper section when made use of.

When you generate single-muon events, you have to change the condition of `SQGeomAcc` in `Fun4Sim.C`.
• SQGeomAcc skips (i.e. not save) an event in which a muon or a muon pair doesn't pass through the spectrometer acceptance, because such event is useless for analysis.
• By default, SQGeomAcc requires a muon pair per event; "geom_acc->SetMuonMode(SQGeomAcc::PAIR);"

When you generate single-muon events, you have to modify `Fun4Sim.C` as follows, so that SQGeomAcc requires a muon per event;

geom_acc->SetMuonMode(SQGeomAcc::SINGLE);

  or

geom_acc->SetMuonMode(nmu_plus+nmu_minus==1 ? SQGeomAcc::SINGLE : SQGeomAcc::PAIR);

Better configurations for J/psi and psi' are available in the E1039-Collaboration/e1039-analysis repository.  Zulkaida could make use of them in "/project/ptgroup/Akbar/*/Fun4Sim.C".https://github.com/E1039-Collaboration/e1039-analysis/blob/master/SimChainDev/phpythia8_Jpsi.cfg ... It produces J/psi and other charmonia (including psi'), where the rate of psi' is much lower than the current configuration
• .
• https://github.com/E1039-Collaboration/e1039-analysis/blob/master/SimChainDev/phpythia8_psip.cfg ... It produces only psi', not J/psi.
• Note:  Even when using new configurations, you should still select the particle of your interest (i.e. J/psi or psi') by its truth mass in `histo.C`.  It is because a random pair (like mu+ from pi+ and mu- from pi-) could be produced from the beam remnant.
• reco_vz
  • reco_vz is the reconstructed position of track (not dimuon) at the target position (i.e. z = -300 cm). Therefore "reco_vz" is always -300 cm
  • The meaning of "reco_vz" is defined in "AnaTrkQA".  Actually the present naming is misleading.
  • When dimuon events are produced in the dump, each track should make the closest approach to the z-axis in the dump region. But "reco_vz" is not the position of the closest approach but the position of the track at z = -300 cm by definition.  "reco_vx" and "reco_vy" are not peaked at 0 cm.
Others??