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Log entry time 17:03:49 on April 21, 2008
Entry number 233621
This entry is a followup to: 233566
Followups:
keyword=Track multiplicitiesI replayed runs 3515 and 3574 with the latest updated TreeSearch code and obtained the attached histogram of the track multiplicities. The green hatched histogram represents run 3515. It looks very reasonable, where the small increase in multiple tracks is expected due to increased random coincidences with higher beam current. It looks like the replay done for log entry 233566 is based on an old version of TreeSearch that is lacking some important updates, so that the sharp increase in multitracks is due simply to more "ghost tracks", multiple tracks with nearly identical track parameters or shared crossing points in the front or back chambers (multiple use of the same hits). The updated TreeSearch code eliminates these, keeping only the one(s) with best chi2.
From the analysis side, the most obvious effect of the higher beam
current is that the replay takes almost twice as long because a LOT more
noise has to be filtered. But the overall track identification appears
still stable and efficient.
A copy of this log entry has been emailed to: jinhuang@jlab.org, moffit@jlab.org, ral5q@virginia.edu, doug@jlab.org
Figure 1
