(1)

Vertex distribution will lead to significant smearing of invariant mass.
PYTHIA J/psi simulation with both leptons in the FMS acceptance:
- vertex distribution (sigma=50 cm)
- no vertex reconstruction included in the analysis
- mass smeared by about 200 MeV

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(2)

Vertex reconstruction with BBC is not calibrated
- TAC difference is EAST - WEST (scale 0.02 ns/ch)
- early time = high TAC, late time = low TAC
- large difference = positive z-vertex (towards FMS)

Correlation with primary vertices from tracks
- very low efficiency (0.2%)
- scale for TAC looks different when no cut on vertex rank is applied (slope should be 100 cm per 300 ch)
- currently just calculating the mean <z_TPC> in slices of BBC TAC-difference
- asymmetric features of tails look consistent, but z_TPC definitely has non-Gaussian peak structure
- (figure includes half of pp200_trans)
- rerunning with cut on vertex rank

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(analysis comments)

StMuDst->event()->bbcTriggerDetector is obsolete
- use StMuDst->event()->triggerData()

StMuDst->event()->primaryVertexPosition()
- same as StMuDst->primaryVertex()->position()
- rank is only available through primaryVertex()