i have refined the cuts a little (since the saturday shift e-mail) and
furthermore now modeled the background and taken it out of the
asymmetries. i now get the following dilutions for asymmetries vs.
missing momentum up to 0.15GeV:
left dilution : 0.346 +- 0.017
right dilution : 0.337 +- 0.014
these results are for about 38kC of data (basically all of our 32deg data
up until yesterday afteroon). assuming a beam helicity of 0.620 +- 0.005,
these dilutions correspond to the following vector polarizations:
left vector pol : 0.558 +- 0.018
right vector pol : 0.544 +- 0.015
which are both consistent to within 1 sigma of each other.
i have included a picture (two, actually; the second is zoomed in) of the
ratio of background-to-real counts vs. missing momentum for the left and
right sectors. the error bars are horrible due to the lack of empty
target data (especially, high missing momentum empty target data); we have
about 10kC of emptry 60cm data. however, structure can still be seen.
at low missing momentum, the background seems to saturate at about a 2%
contribution. as one rises up to 0.25GeV missing momenta, the background
becomes more dominant to a tune of nearly 15% (presumably b/c of the
aluminum target's high momentum density distribution function compared
with that of deuterium). don't believe the plots above 0.3GeV or so
(just not enough statistics).
this plot fairly closely resembles the one that igor produced in his
thesis (though NIKHEF's background seems to have dominated by about a
factor or 2 more than ours does).
more empty target data is needed. i would remind people that, while
determination of Gen only requires low missing momenta, any tensor-physics
as well as non-Gen vector physics will all require higher missing momenta
-- say, around 0.3Gev and up. our background determination is currently
pretty bad in this region.
aaron
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