Run4 Fiducial Match between Real and MC Purpose WIS noticed a discrepancy between Real and MC Dch Zed Dch Zed was narrower in MC compared to data VU extended the discrepancy effects to the study of matches with the outer trackers and also in azimuth Generally MC looks to have a bigger live area than Run4 data, even when nominal Run4 average dead channel maps are used If not fixed then the discrepancies will lead to acceptances factors which are too large meaning dN/dy will be too small Methods Dipali is making corresponding fiducial cuts between the two dimensional Azimuth vs Zed hits for each outer detector systems Charlie is looking at the one dimensional distributions between real and MC to spot major discrepancies (plus or minus) With new fiducial cuts the discrepancies should be minimized May 25, 2005 Run 4 Fiducial Match for Drift Chamber

One dimensional Real and MC distributions Data All the valid ++ runs of Run4 stripe 2, 2% of each CNT segment leads to a 1 GByte NTUPLE with track association parameters Using 40 Phi->KK CNTs simulated generated by Dipali in ++ field Real and MC histograms are normalized according to total entries Cuts Reconstructed momentum from 0.2 to 2.1 GeV/c Require Dch Quality = 31 or 63 Require Dch Zed to be -75.0 to +75.0 cm Showing only the Dch Zed and Phi (Azimuth) distributions here Distributions are in the four quadrants for Dch Azimuth comparison, and separated into East and West for the Dch Zed comparison Future distributions for outer detectors will have 3-sigma matching cuts in Phi and Zed, and will likewise be in quadrants or halves May 25, 2005 Run 4 Fiducial Match for Drift Chamber

Azimuth for Dch SouthWest Best result, practically no significant discrepancies After normalization by total entries After normalization by total entries May 25, 2005 Run 4 Fiducial Match for Drift Chamber

Run 4 Fiducial Match for Drift Chamber Azimuth for Dch NorthWest Almost as good as SouthWest, discrepancy at ~ -19 degrees May 25, 2005 Run 4 Fiducial Match for Drift Chamber

Run 4 Fiducial Match for Drift Chamber Azimuth for Dch SouthEast Somewhat worse, especially 165o - 168o, 172o - 178o May 25, 2005 Run 4 Fiducial Match for Drift Chamber

Azimuth for Dch NorthEast Unacceptably bad, 1400 - 165o, 175o -200o There must be a mistake somewhere May 25, 2005 Run 4 Fiducial Match for Drift Chamber

Run 4 Fiducial Match for Drift Chamber Azimuth for Dch NorthEast Quality = 63 Only No shape change from including Quality = 31 tracks May 25, 2005 Run 4 Fiducial Match for Drift Chamber

Run 4 Fiducial Match for Drift Chamber Zed for Dch West Looks good except at Z = 0 and at edges Suggest a +/- 70 cm Zed cut instead of +/- 75 cm May 25, 2005 Run 4 Fiducial Match for Drift Chamber

Run 4 Fiducial Match for Drift Chamber Zed for Dch East, Similar to West except Z=0 discrepancy slightly broader May 25, 2005 Run 4 Fiducial Match for Drift Chamber

Summary of One Dimensional Distributions from Dch West azimuth looks better than the East azimuth The North East azimuth comparison is particularly bad Need to confirm that the simulations were done with the latest Run4 Au+Au 200 GeV dead channels map for the Dch The Dch Zed comparisons are OK except for the Z = 0 discrepancy and a slightly larger extent in real data compared to simulation More comparisons will be forthcoming for the outer detectors These will largely be influenced by the Dch comparisons May 25, 2005 Run 4 Fiducial Match for Drift Chamber