SVT-TPC Vertex Correlation

This data is from 100,000 events from st_physics_3009* which is ppMinbias with a reversed full field. Of the 100,000 events looked at only 25,770 events had a primary vertex, as located by the TPC pplmv vertex finder within +-30cm. These are the events considered here. The TPC vertex finder was run with the beam line constraint turned on. The SVT vertex finder was run after Jun's tuning for pp running and after Marcelo's first rough alignment corrections from the survey data.

Fig. 1. The number of TPC primary tracks

Fig. 2. The number of good svt hits. Good = flag < 4

Fig. 3. Z Vertex from SVT (x axis) vs Z TPC. Units are cm

Fig. 4. Z SVT- Z Tpc. Black - all events, Red - N TPC primary > 10. The mean is now at -0.05cm (good) for both selections. The width is 0.28cm (0.24cm for the n primary > 10). So resolution is not dependant on the number of primaries - good.

Fig. 5. Z difference vs Z TPC

Fig. 7. OK doesn't belong here but I thought it looked good.(Jun now has MUCH nicer plots).

For more information on this technique see here..

For more general Year 2001 studies see here

Helen Caines
Last modified: Sat Jun 29 15:42:14 EDT 2002