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    User name Feng

    Log entry time 07:50:32 on January 29,1999

    Entry number 11242

    keyword=BCM Problem Understood

    We realized that the previous BCM problem was actually related to some timing mistake in hadron arm. Wang will present more detailed data on this. Here is some brief description:

    There is about 200 us time interval between two helicity pulses. Thus Q+ + Q- should be smaller than Qtot. Assuming consant current, we should be able to find a relation like (Q+ + Q- - Qtot)/Qtot ~ - 1 x 10^(-4). And we do find for the elctron arm runs, this formular are fufilled. However for the hadron arm, we find for the charge information derived from upstream BCM x1, x10, this formular was fufiled very well, for upstream BCM x3, it's not so well, but still smaller than 0. However for downstream BCM x3, x10, the results are always greater than 0! So there must be some problem with the timing information for hadron downstream BCM x3, x10, which we need to figure out.

    Actually, when Wang plotted the charge asymmetry using hadron arm upstream BCM x10 charge information, it agreed very well with the Happex result.