1. QM2004 Version1 Measurements of the  ->     with PHENIX in Au+Au Collisions at 200 GeV at RHIC PPG016 Figures with Final Approval Charles F. Maguire for the PHENIX Collaboration Poster Presentation at QM’04

2. QM2004 Version2 1.dN/dm T dy vs m T, minimum bias (“All East”) 2. dN/dm T dy vs m T, 0-10% centrality 3. dN/dm T dy vs m T, 10-40% centrality 4. dN/dm T dy vs m T, 40-92% centrality 5. m T integrated dN/dy vs participant 6. m T integrated dN/dy per participant vs participant 7. Temperature vs participant 8. Resonance mass centroid vs participant 9. Resonance width vs participant List of Plots: with final approval Draft AN Available

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12. QM2004 Version12 What was included in the AN (Table 47, page 51) Mass gate (2.6%), background normalization, (0.75%) functional form (2.3%), embedding (0.9%), m T range (3.3%). Leads to 4.9% in minimum bias systematic error What was left out of the AN (Want to be conservative here) True size of embedding error (from Ralf) 4% in singles ---> 7.8% in pairs Corrections to singles acceptance as calculated from the MC cuts oMC dispersions (track matching, PID) were tuned to the real data widths: leads to a 3% change which was put into the correction factor ---> 3% pairs correction factor uncertainty Track matching was 3-sigma, PID cut was 2-sigma Losses matter more since adding in background particles will increase the combinatorics which can be measured very precisely (S/B will get lower) oFiducial uncertainty: Only fiducial cut was in the Dch at +/- 75 cm. Used nominal geometry for Dch/PC1/TOF and for Dch/PC1/PC3/EMCal Fiducial systematics in the past were estimated at 4%, with actual checking Without checking we assume 6% in singles (for example, PC3 area = 400 cm x 400 cm --> 12 cm delta in each linear dimension) ---> 12% pairs uncertainty oRun-by-run correction: This was studied carefully in the AN with a final estimate of ~1% Adding What was left out to What was included (4.9) 2 + (7.8) 2 + (3.0) 2 + (12.0) 2 = (15.4) 2 ---> 15.4% systematic estimate Check with different subsystem results on next slide Back-up Slide: Systematic Errors Revised

13. QM2004 Version13 Back-up: Self-Checking of the Systematic Error There are actually two almost completely independent data sets: TOF-TOF and EMCal-EMCal with separate systematics (except embedding) A third data set TOF-EMCal combines one Kaon from each subsystem oShares the systematics of the two systems oNew systematic of relative geometry between the two subsystems Table 16 (page 32) shows the minimum bias dN/dy for the three subsystems TOF-TOF 1.38 +/- 0.36 TOF-EMCal 1.42 +/- 0.18 EMCal-EMCal 1.47 +/- 0.26 Observations from the subsystem comparisons over the same m T range oDeviation of TOF-TOF from EMCal-EMCal is 6.5% (uncorrelated systematics) oTOF-EMCal is intermediate between between TOF-TOF and EMCal-EMCal As expected, if the relative geometry between TOF and EMCal is not badly wrong oConclusions from the subsystems comparisons oDifficult to believe that TOF-TOF and EMCal-EMCal each should have 20% systematic error oConclusion would be stronger if the fit errors were smaller

14. QM2004 Version14 Back-up Slide Systematic Errors Analysis Comparison with Single Kaon Analysis (AN187)  Single Kaon systematic errors for dN/dy (Table XV, page 47) oErrors are 0.5*(Maximum - Minimum), no division by sqrt(3) oError from cuts and multiplicity 11.6 - 8.3 % (central - peripheral) oError from extrapolation 5.7 - 7.4 %: goes to 3.3 - 4.3 % if divided by sqrt(3) oTotal error 12.9 - 11.1%: goes to 7.4 - 6.4 % if divided by sqrt(3) oError is dominated by cuts, e.g. mis-identified particles      Systematic Errors for dN/dy (page 51, Table 47) oParticle identification background not a factor with combinatorics (WRONG) oBackground under peak known to ~1% level with sqrt(N + N - ) ratio oMajor MB systematic error: mass gate (2.6%), m T range (3.3%), function (2.3%) Extrapolation error is the combination of m T range and function = 4.2% Comparable with extrapolation error from single Kaons (MISSED FIDUCIAL) oAllEast dN/dy systematic error for MB is 4.9% (includes sqrt(3) division) oHave also looked at the +/-15 MeV mass gate as baseline leads to mass systematic error of 5.3% in dN/dy and 1.3% in T Much worse than +/-5 MeV mass gate because of worse S/B ratio

15. QM2004 Version15 Back-up Slide Sources of Mass Systematic Error Normalization and Mass Gate  Tabulated in Table 57 (page 64) of the AN  Computed for each of the five centrality bins and minimum bias  Systematic errors is 0.03 MeV for minimum bias All East, and ~ 0.05 MeV at each centrality bin  These systematic errors are a factor of ~4 below the statistical errors and much lower than the 0.70 MeV discrepancy with the PDG value Magnetic field Uncertainty  Error in magnetic field scale factor will systematically raise or lower the single particle momentum of each pair member  Magnetic field scale factor uncertainty had not been used before in the AN  Magnetic field scale factor uncertainty is available from AN172 (February 22, 2003) Scale factor = 1.022 +/- 0.017  Derived from a study of identified hadron masses in the East Arm Factor of 1.022 used in the “afterburner” code for v03 nanoDSTs  We don’t know the absolute momentum scale to better than 1.7%

16. QM2004 Version16 Studied in simulation  Used same EXODUS Phi->K+K- files from WIS as were used for efficiency correction factors  Applied random resolution single particle errors as in AN172  Changed the single particle momentum systematically according to an externally input systematic scale factor  Reconstructed pairs according to the PHENIX acceptance  Compared the reconstructed pair mass to the original mass  Results from a 1.7% systematic scale uncertainty  +1.7% changes the mass centroid by +0.80 MeV  -1.7% changes the mass centroid by -0.89 MeV ===> -0.70 MeV discrepancy within systematic uncertainty range Equivalently, the scale factor should have been 1.034 instead of 1.022 Back-up Slide Effect of Momentum Scale Systematic Error

17. QM2004 Version17 Central Arm momentum reconstruction details  Input data are the bend angle and Z position as measured by BBC/DCH/PC1  Input data are correlated with a look-up table fieldIntegral.dat  There is only one fieldIntegral.dat file for all particle types Effect of differential energy loss between particle types is not accounted Future Kalman filter software will make this correction  Effect of energy loss on single particles studied in simulation  Looked at pions and kaons from 0.3 to 2.0 GeV/c  Ran PISA with and without energy loss activated  Compared the difference with/without energy loss Back-up Slide Energy Loss

18. QM2004 Version18 Back-up Slide Energy Loss Effect: (Reco - True)/True True Momentum 0.10 GeV/c bins Effect of Energy Loss on Pions Effect of Energy Loss on Kaons 0.35-0.5% (+/- 0.1%)-0.93% (+/- 0.08%) 0.450.0% (0.1%)-0.40% (0.07%) 0.55-0.1% (0.1%)-0.22% (0.07%) 0.65-0.1% (0.1%)-0.22% (0.07%) 0.75-0.1% (0.1%)-0.08 % (0.07%) 0.85-0.15% (0.12%)-0.10% (0.07%) Unaccounted for energy loss is another source of (smaller) systematic error for the single Kaons, at least up to ~0.6 GeV/c Effect on pair mass is ~0.1 MeV from simulations Much smaller than scale factor effect Compare these sizes with the 1.7% scale factor uncertainty