Hi John and all
Again, some T20 plots.
1. T20_July.ps: results from the data collected so far. including data
taken in Feburary with 40cm cell and one shorted holding field, March 40cm
47degree runs, May 60cm 47 degree runs, May 60cm 32 degree runs, and July
60cm 32 degree runs up to the TDC module swap.
compare counts to Monte Carlo for the 6 bins, normalized to the total
counts which is dominated by the first two bins:
Q2 (GeV/c ^2) Counts in data data/MC
0.146 62502 101%
0.205 19310 100%
0.281 4659 90%
0.376 722 66%
0.518 138 55%
0.681 51 85%
Still missing events in higher Q2 bins. The 85% "efficiency" in last bin
is questionable as withing the bin(0.62-0.9 GeV/c ^2), I can see deviation
of cross section compare to MC. With better identification, I should be
able to reach better efficiency.
But I am runnig out of quick tricks to play. I need more time to
understand the tdc/adc in the TOF and NC to actually apply them in PID.
Also I d like to plea for better understanding of Wire Chamber again.
2. T20_projection_mc.ps: projection with current rate: 0.52/C, current
Pzz=0.58, 300kC more charge. Data at hand are also included through
weighted average.
John raised the question of error size in the projection plot I sent last
time. I checked and found that due to some not so clean cuts, the counts
in last few bins did not scale as MC. In fact, at that time I included
quite a few runs after the TDC module swap but with the old sc_cal.
Counts in one sector at high Q2 well exceeds MC prediction. Thus the error
bars in high Q2 bins in previous projection plot is under estimated.
To avoid confusion this time, counts projected by MC are used for the
projection.
3. T20_projection_mc_600k.ps: projection with same conditions but 600kC
more. This is more directly comparable to the projection I sent out a few
days ago. 600k corresponds to 13 weeks running with 100% beam efficiency
at 80mA. The size of error bars are arround 75% of those in the projection
for 300kC more running. It s not exactly root of 2 since 180kC of data are
included too.
Bin sizes are adjusted to spin off a sixth bin at 4.19fm-1. it covers 0.62
GeV/c ^2 and up.
I did not put any systematic error estimation on these plots.
John pointed out my mistake in computing the systematics from error in
Pzz. The proper way to determine that is simple scale T20 by the same
amount. That is, +-10% error in Pzz causes +-10% error in T20.
I did not include systematic due to resolution in the angles either
because I have yet to figure out how to integrate them for runs with
different spin angle.
Chi
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