[d2n-analysis-talk] positron asymmetry and negative/positive polarity cuts

[posik at jlab.org]

Hi all,

   I just finished computing the raw positron asymmetry from our positive
polarity 4.7GeV run set (runs 2199-2122). All of these runs took place
while running the accelerator in the unbalanced setup. They all had 1/2
wave-plate IN and a target spin of 270 deg. To select good positrons, I
used identical cuts to those that we have been using to select our
negative polarity electrons. You can find a list of the negative
polarity electron cuts, their purpose and what they look like here:

      https://hallaweb.jlab.org/wiki/index.php/Analysis_Tools#BigBite

I still need to add the Cerenkov cuts to the wiki cut list above.
In addition, I also took a look at how the above negative polarity
electron cuts behave in the positive polarity mode. A side by side
comparison of the cuts can be found here:

https://hallaweb.jlab.org/wiki/index.php/Analysis_resources_for_d2n#21_April_2011_Meeting

under the April 21 meeting.

In the plot asy_compare.eps I plotted the raw positron asymmetry for
positive polarity (runs 2199-2212) shown in red, and the raw electron
asymmetry for the negative polarity (runs 2024-2195) shown in blue.
In the plot asy_compare_zoom.eps I show the same plot but zoom in around 0
in order to see the asymmetry of the lower x-bins.

There does appear to be a decent positron asymmetry here for the target
S=270 deg. One thing that I noticed in comparing the negative and positive
polarity cuts, was that it appeared we may be cutting a little too much on
the E/p in the positive polarity.

-Matt


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