TransverseAnalysisMeeting June 16 2020

From PREX Wiki
Jump to: navigation, search

Back to Main Page >> Transverse Analysis Meetings

previous meeting << >> next meeting

Logistic information

 BlueJeans calling instructions:
 Bluejeans link:


  1. PREX1 AT systematics summary: Ciprian haplog4136 (Bob's original haplog2594)
    1. Beam False Asymmetries
      • KK: make sure the regression/dithering cancellations are not happening with AX and EX (ie correlations between BPMs); KP: the setup was different for the AT runs so it would be good to check with the independent set of BPMs. We can postpone this work for the AT data until things get more clear with the main measurement
    2. Qsq differences
      • KP: optics DB is being reoptimized for both PREX and CREX but should be a solid enough state by mid July to get a Q2 uncertainty
    3. HRS L/R differences
      • KK: can't see how this would come in beyond Q2 so at first pass we don't need to worry about it
    4. Carbon subtration from Pb
      • KP: we need to track down documentation for the Pb (and Ca) targets to make sure we know the exact ratios of C/Pb (Ca40/Ca48). Eventually this will need a simulation to pin down.
      • KK: at 2GeV this will be more important since the correction is larger
    5. Polarization direction (magnitude and direction)
      • KP: while we didn't see large difference in the polarization measurement over the entire run we should stick to runs close by to the AT runs to be sure.
    6. Sign of asymmetry
      • KP: we took the data for the sign and we need to bring it up and analyze it
      • KK: we need to know if right-handed goes to up or down. CG: this can be checked with the Mott in addition to checking the uncertainty of the degree of vertical polarization
    7. Theory predictions
      • KK: M. Gorchtein is working on predictions and may have something by mid July
    8. Energy fluctuations
      • KK: the only thing that could matter would be radiative tail and if the C/Pb ratio changes. Expect both to be small compared to the statistical uncertainty.
    9. Detector non-linearity
      • DA: for the nonlinearity we can recover the non-linearity from bench studies for each of the running conditions. KP: we should look at the charge correlation as well; we tracked our pedestals and should be able to look at the beam noise during the run itself (stardard plots)
    10. Isotopic purity:
      • KK: for Ca48 we will need to do a Ca40 correction. CG: Ca40 is 99.965 pure so any correction will not matter (docDB306). KP: we should check the logbooks for PREX1 to see what we discussed for that.
    11. Inelastic contributions:
      • KK: we need to say something about the inelastic contamination and the asymmetry related to those for all of these measurements. We should keep this as a hw to check the logbook what was discussed for PREX1 and ask Bob as well.
  2. CREX AT runs update: Weibin & Robert
    • WZ: redid dithering with 1x BPM and the last 2 runs the dithering has large uncertainties; looking at it vs time we can see it much larger in both L and R. It's not visible in the average (only in DD).
    • WZ: the dithering slopes: we only have a large difference for the last run, but not the second to last. CC/KP: We need to investigate further, details of the dithering (slopes and cycles)


Weibin Z, Ryan R, KK, Kent P, Devi A, Ciprian G, Sakib R, Cameron C

Send regrets: David A