Hi, just for your entertaiment, I send out this T20 results plotted over
world data.
T20 from ed elastic asymmetry from run 5800-6052 is show in the atatched
ps figure T20.ps. T20 from May 15-20 runs are in T20_May.ps
red points are BLAST data. the three black squares are late NIKHEF data.
The empty square at 1.58fm-1 is the NIKHEF data I understand we wished to
normalized to.
by convention, it is converted such that theta electron is at 70 degree.
calculated T22 value is used to seperate T20 and T21 from the two
measurements in both sectors. the proposal proposed running with pure
longitudinal spin angle for speration of T22.
error bars are pure statistical. resolution in Q is NOT included,
resolution in scattering angle is NOT included for either. Error in
target spin angle is NOT accounted for either.
It turns out the result is very sensitive to spin angle. This plot assumes
spin angle at 49 degree. Fit for polarization is not very sensitive to
spin angle, so the sensitivity is largely in kinematics. using spin
angle=47 degree will move the data points downward such that the error
bars barely touch the dashed curve(Bunchmann full). with 45 degree the
data points are further down. Could be a mistake in my code, I will check
when I can do it not at 4am.
For March data, the first and last data points are in the middle of no
where.
At high Q2, the timing seperation between ed elastic and knocked out
proton is less clear, given the resolution of the detector, I would think
the data point contains a lot of e'p background.
At lowest Q2, perhaps it is caused by poor reconstruction. May runs have
smaller "hole" in electron right/deuteron left cross section. In the
meantime, the lowest Q2 data point is more consistant with the others.
All T20 absolute values are on the large side. could be: spin angle, could
be polarization value obtained from fits is too small. Will investigate
further.
Chi
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