Run 7 (200GeV AuAu)
The interest of doing a beamline constraint for this data (200 GeV AuAu) has been expressed mainly for reconstructing UPC vertices. Perhaps there may be eventual interest in using it for very peripheral collisions as well (AuAu hadronic interactions with just a few participants).
Using minbias triggers from 206 fills starting with fill 8477 (day 95, April 5, 2007). The query used to find runs is attached.
- mb-vpd
- mb-zdc
Here are the results of the calibration pass:
I have studied dependencies on luminosity (none seen, I am using luminosity scaler-based corrections for SpaceCharge and GridLeak in the calibration passes), vertex ranking (none seen for ranking greater than -3), and multiplicity (none seen for multiplicities above 50). I also tested using the EbyE SpaceCharge+GridLeak correction method and there's no effect versus using the luminosity scaler-based method for this calibration.
There are some notable issues, particularly around days 143 (fills 8838-8845), 150 (fill 8878), and 156 (fill 8912). Fill 8912 in particular looks pretty bad, and I see particularly notable backgrounds in the BBC singles and ZDC east singles rates (which don't show up in the coincidence rates). Here's the log10 of BBC singles sum, with fill 8912 highlighted in red:
Another diagnostic for the quality of the data is to look at the spread of reconstructed vertices. So here are the mean (blue markers) and spread (red lines) of primary vertex x (top) and y (bottom) positions versus fill for vertices with abs(z) < 10cm (the black circles denote the locations of fills 8838-8845 and 8912, and the errors on the means are too small to be seen on these plots). Vertices have been weighted by sqrt(multiplicity).
There are a few with spreads of about 1mm or more, and I am still looking into these.
Dec. 8, 2007
The following fills have been dropped from use after studies:
8478 - large transverse spread in vertex reconstruction, using previous fill 8491 - large transverse spread in vertex reconstruction, using previous fill 8592 - odd slope, previous fill (8590) just as good 8761 - bogus fill number - using 8762 8838,8844,8845 - high backgrounds at start of RFF running, using next fill 8849 8878 - questionable backgrounds, using previous fill (8875) 8879 - large transverse spread in vertex reconstruction, using 8875 also 8890 - odd slope, previous fill (8889) just as good 8900,8901 - odd slope, previous fill (8897) just as good 8912 - high backgrounds, using previous fill 9024 - large transverse spread in vertex reconstruction, using previous fill
The remaining tables have been inserted into the DB, and the final plot of values is as follows:
