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    User name tajima

    Log entry time 12:22:28 on March 20, 2006

    Entry number 167583

    keyword=proton coin time plot for 3040 (2H)

    Attched below shows the proton coin time for run 3040 (2H)
    "na.nd.s1.hit_tof[0]-(B.s.time[B.s.t_pads[0]])/2.+0.05*D.ctimeL1A"

    Cuts applied (for the black histogram) are:

    BB total energy cuts (B.ts.ps.e[0]/2.+B.ts.sh.e[0])>2000
    Cuts on scin time: B.s.time[B.s.t_pads[0]]>50&&B.s.time[B.s.t_pads[0]]<70
    Tracking cut: B.tr.n==1 (this means tracking successful)

    To make the red plot, I further applied the following cuts
    Electron Momentum larger than 1GeV: B.tr.p>1.0
    Coplanarity cuts: abs(na.nd.n1.hit_xpos/4.5+B.ts.sh.x[0]/2.4-0.1)<0.2")

    The peak width is still wide (~20ns), but the tracking cuts are pretty
    effective in selecting elastic events.




    Figure 1

    p_cointime_3040_w_track_success.ps