The STAR experiment

Minutes

No issue with TPC hardware
-Have adjusted methan content to make Vdrift more constatnt; there were several period in Feb with variations.
- powerdips and magnet trips during last weeks running.

The two runs in day 38 and 66 had outer sector 19 exhibit large excess of charge that extended for all pad and rows for about 150 timebins. See blog entries in https://drupal.star.bnl.gov/STAR/blog/videbaks/tpc-qa-2021 near top of page

Most likely a faulty GG driver board . Alexei suggested looking at signals from board during next maintanence day (unless it get really bad). Will talk to Tim on this.

Gene reported looking at laser un running 7.7 GeV for local clock vs. coll clock. Did not see any different between laser positions. Now looking at prompt hits for two conditions, (UPDATE: small shifts seen for the entire TPC by 14.1 ns, but not on the scale of 1 time bucket; documentation is here)

Yuri show plots 
these are references for plots which we discussed today
1. Comparison RF and FF  https://drupal.star.bnl.gov/STAR/system/files/TpcCSTransformations_0.pdf
-- the FF has only 34k events.Alignment same for two settings.
2. QA plots for RunXXI (express production) : https://www.star.bnl.gov/~fisyak/star/BES/
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3. Lasers for different fields
-- no clear pattern. Sector 20 seems consistent for all fields. 20 has best lasers
4. Prompts for different VPD timing cuts
-- shows dependence on collisions timing (sum of VPD timing)
The last plots on meeting page only

Meeting minutes:

GMT - the code stransferrend to dev compiles, but crashes. The reasons seems to be forbidden access to the tree data structure. David will test if the is also tru in  .DEV2

Robert Licenik managed to recreate the embedding Pythia in to zero bias pp data. The results are different from what Dima showed. The reason could be that Dima was using a private reproduction of the data.

K->3pi update. The  bump in the reconstruction efficiency as a function of transverse radius is also in the MC. Possible cause could be a track splitting. It was suggested to check the invariant mass. It could also be a feature if the KFP when extrapolating into a region without hits. Need to try changing the KFP cut values.