June 11, 2002

1st method (Zhangbu) to get MAXIMUM centrality at 20 GeV

The method has been described earlier (see Zhangbu's method ).
The present profile plots are an improvement and supersede previous one. We also include results for 200 GeV.

a) correlation_au20.gif
b) correlation_au130.gif
c) centrality_cuts.gif
The fits were done using the data only up to Nch(eta1)=Nmax, as shown in the figures. For example, for au20, only data wich Nch(eta1)<=320 was included for the fit.

d) correlation_au200.gif

Here are details of what was done:
0) Files :
au20: /auto/stardata/starspec3/flow_pDST_production/reco/minBias22GeVZDC/ReversedHalfField/P02ge/2001/
au130: /auto/stardata/starspec/schweda/pDST/P01hi/minbias/global/
au200: /auto/stardata/starspec2/flow_pDST_production/reco/MinBiasVertex/ReversedFullField/P01gk/2001/

1) I've verified independently that mUncorrNegMult and mUncorrPosMult indeed correspond do the number of tracks as defined in the code that produces pDst. See Masashi's e-mail to Roppon:
mUncorrNegMult and mUncorrPosMult are copied from StEventUtilities function uncorrectedNumberOfNegativePrimaries(const StEvent&) and uncorrectedNumberOfPositivePrimaries(cont StEvent&). It is number of tracks that are: number of Fit points >=10 |eta|<=0.5 DCA < 3.0 cm ------------------------------------------------------------------------