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Relative Luminosity Analysis from PHENIX

Relative Luminosity Analysis from PHENIX. RIKEN BNL Research Center KAWABATA TAKAHIRO. Instruments. GL1P scaler - crossing-by-crossing scalers for 120 crossings (60 crossings in run 2) - live time only - consists of 4 channels M.B. ( BBCLL1 NTCwide )

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Relative Luminosity Analysis from PHENIX

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  1. Relative Luminosity Analysis from PHENIX RIKEN BNL Research Center KAWABATA TAKAHIRO

  2. Instruments GL1P scaler - crossing-by-crossing scalers for 120 crossings (60 crossings in run 2) - live time only - consists of 4 channels M.B. (BBCLL1NTCwide ) NTCnarrow / BBCLL1 / ZDC (N&S) • Luminosity monitors • BBCLL1 (|Z| < 75 cm) • NTCwide • NTCnarrow (|Z| < 40 cm) • ZDC NTCS NTCN BBCN

  3. Relative luminosity • no critical item for AN measurement in run-2 • important for ALL measurement in run-3 • 10–4 level precision required for sub-% level asymmetry measurement • normalization in the cross section measurement stability of each luminosity monitor ? • which is the best ?

  4. Scaler Counts GL1P counts vs Crossing number - #10 and #30 … large emittance - #15-19 … abort gap (Yellow) - #55-59 … abort gap (Blue) Only NTC counts beam-gas events. ZDC has low statistics.

  5. Specific Luminosity • Specific Luminosity • Normalized and plotted as a function of crossing number • Specific luminosity fluctuates by 2-5%. • NTCn is less stable. - only NTC counts beam-gas events. • ZDC has low statistics.

  6. RZDC/BBC RBBC/NTCn Fill Number Systematic Error on Relative Luminosity Ratio between GL1P channels must be one. - Shown with the statistical errors by solid circles and lines. Evaluate for random classification.- All bunches were randomly sorted into Group A and B. - Repeat the calculation 400 times. - Shown by shaded area. Systematic error has fill dependence. - ~0.3% for good fill. - Improve by adding all fills up to ~0.2%.

  7. Time Dependence • Spin relative luminosity RXY is plotted as a function of time. - solid lines .. Statistical error - shaded region .. Systematic + Statistical • Each point shows 10,000-sec time slot. • Background colors indicate fills. • RXY has a fill dependence. RZDC/BBC RBBC/NTCn Time (DD/MM)

  8. Correlation between Specific Luminosities • Correlation between spe. lumi. are plotted. • Fluctuation of spe. lumi. is not important. • Systematic errors depend on widths of loci.

  9. Dependence on Z-vertex width • Differences in specific luminosities are plotted as a function of the Z-vertex wdith. • Dependence on Z-vertex width is not clear. • Bunch selection by Z-vertex width did not work well.

  10. Bunch Selection Several bunches with the bad spe. lumi. are excluded - shaded region …. before the selection - black line …. after the selection - red line … statistical error - solid circle … RXY Bunch sel. slightly improves bad fills, but not good fills. Results on RXY are ….- NTCn/M.B. … 1.0005 +/- 0.10% - BBC/M.B. … 0.9974 +/- 0.36% - ZDC/M.B. … 0.9981 +/- 0.37% - BBC/NTCn … 0.9969 +/- 0.41% - ZDC/NTCn … 0.9975 +/- 0.44% - ZDC/BBC … 1.0007 +/- 0.15%by summing up Run40117-40655. RBBC/NTCn RZDC/BBC Fill Number

  11. Summary • GL1P data from PHENIX were analyzed for relative luminosity study. • Systematic error has a fill dependence. - ~0.3% for good fill, 0.15% for Run40117-40655 - Small dependence on Z-vertex width - Slightly improved by bunch selection • Procedure for fill diagnosis should be established.

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