there is about 17kC of polarized deuterium data since last thursday (there
is a little more such data, but root yells about the lrn files not being
closed correctly).
this data gives me a QE ep rate of 9.5 events/C. this is UP about 60%
compared to the corresponding rate before the most-recent shutdown.
take a look at the attached plots of the bema-vector asymmetry versus
missing momentum and Q2, respectively. all show a massive increase
in vector polarization:
dilution | vec pol (assuming h = 0.64+-0.01)
(left) (right) | (left) (right)
------------------------------------------------------------------
vs p_m : 0.657 +- 0.026 0.576 +-0.020 | 1.027 +- 0.044 0.900 +- 0.034
|
vs Q2 : 0.688 +- 0.027 0.611 +-0.021 | 1.075 +- 0.045 0.955 +- 0.036
ummm... yeah. maybe this is a little too good. isn't there a realistic
maximum vector polarization (less than 100%) that one could hope to
obtain???
the plot versus missing momentum for polarization perpendicular to q
(i.e. the left sector plot) looks especially good for two reasons.
1) the asymmetry's "frown" shape for p_m < 0.2GeV shows up very well in
the data.
2) though still a little statistics limited, the asymmetry's rise to
positive values for p_m > 0.3GeV is also very visible.
i would once again remind everyone that much more empty target data is
needed in order to nail down the background contribution at p_m > 0.3GeV.
aaron
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