Date: Sun, 27 Oct 2002 17:42:54 -0500 (EST)
From: Junjie Zhu <junjie@wam.umd.edu>

Hi, All:

I looked at zee events and plotted the invariant mass for two good EM
candidates (The requirement for two good candidates are: id==10 or
abs(id0==11, pT>20, emfrac>0.9, iso<0.15, HMx<15, no track match
requirement), and the plots are attached:

For Page 1: (here I use em_util package which applies some corrections for
the geometry and energy resolution)

The top plot is the invariant mass for MC, the width is now 4.11+/-0.19
GeV (for previous MC, the width is about 3.0 GeV), but now the peak
is 87.39+/-0.18 GeV.
The bottom plot is the invariant mass for data processed with p13.00.00,
the width is 4.687+/-0.61 GeV and the peak is 90.87+/-0.52 GeV.

For Page 2: (here I use D0ChunkAnalyze, read all information from EM Chunk
directly, since I am a little bit afraid that em_util does not treat MC
and data properly)

The top plot shows the invaraint mass for MC, the width is 3.649+/-0.267
GeV and the peak is 85.28+/-0.19 GeV.
The bottom plot shows the invariant mass for data, the width is
4.94+/-0.91 GeV and the peak is 91.17+/-0.63 GeV.

Cheers,
Junjie