STAR QA Board

[Benjamin Kimelman <bkimelman@ucdavis.edu>]

Hello QA board,

Daniel and I have spent some time this morning going through the QA I presented regarding the drop in the mean pion yield on days 73-75 and days 81 & 82. These same dips can be seen in the mean number of primary tracks, mean refMult, mean bToFMult, and the good event fraction. HLT does not see any of these issues. We have also looked through the shift log and the minutes from the STAROps meetings for these days and have not found any explanation as to why we observe a 25% drop in these quantities over these runs.

Daniel and I did a side-by-side comparison of a good run (20078044) and one of the runs where this problem exists (20081016). These are both the first full run of the fill (after the injection run). We compared the shift plots for these two runs and found no differences. We also compared the HLT plots and again found nothing to be different. Looking at my QA from this production for these two runs (found here: https://www.star.bnl.gov/protected/lfsupc/bkimel/productionQA/AuAu_19p6GeV_2019_calib/runs/AuAu_19p6GeV_run_20078044_productionQA.pdf and https://www.star.bnl.gov/protected/lfsupc/bkimel/productionQA/AuAu_19p6GeV_2019_calib/runs/AuAu_19p6GeV_run_20081016_productionQA.pdf) there is one obvious difference that can be seen on page 5: the eta distribution for run 20081016 had a dip around eta=0, as do all of the runs corresponding to this issue.

Additionally, looking at my QA from FastOffline, these issues do not appear. We believe that this is an issue with the calibrations and that it should be investigated on that end.

I have also decided to test out Jira and created a new issue for this on there.

Ben Kimelman

Ph.D. Candidate, Nuclear Physics Group

UC Davis

He/him/his