[d2n-analysis-talk] Positron to electron ratio information

[posik at jlab.org]

Hi all,

   After going over my analysis talk for the Hall A meeting on Friday, and
having Brad ask how our positron/electron ratios compare to other data,
I decided to poke around the transversity logs a little and found some
Class positron/electron ratios. Below you will find a Class paper that
has some positron/electron ratios in it. In particular figure 2 on page
3. Also from the paper,  I am attaching a .png that shows the
positron/electron ratio on NH3.

 Ratios from both figures jump above 20% for scattering energy below 1GeV.
Looking at the attached image, it seem that at a scattering energy of 600
MeV, the positron/electron ratio is about ~40%.

 What we see in BigBite is ~70% and the LHRS Dave says is ~25% in the same
region at 4.7GeV beam energy. Dave also tells me that at 5.9GeV he sees a
positron/electron ratio of ~35%, which is pretty close to what the Class
ratio shows for a beam energy of 5.77Gev and scattering energy of
~600MeV. Of course these are different targets that I am comparing here,
but it seemed interesting .

 Also, looking through the transversity long analysis note, they have a
table that puts there photon induced e- contamination at 55.8% at
momentum of 0.6-0.8 GeV.


-Matt

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