[Frost] Correction

[Michael Dugger]

Hi,

I was having a difficult time understanding Priya's plot on slide 6 of her 
presentation and, it turns out, my comments regarding the plot were 
incorrect.

This is how I now understand the plot (Priya, please correct me if I am 
wrong about this):

There is some parameter Priya obtains from fitting (I will call this parA) 
that represents target_polarization*T. This parA is determined for set 2 
and 4. (Let me call parA from set 2 parA2, and parA from set 4 as parA4.)

To obtain the points on the plot an asymmetry is formed:

asymmetry = (parA4/mtp4 - parA2/mtp2)/(parA4/mtp4 + parA2/mtp2) ,

where mtp2 (mtp4) is the measured target polarization for run set 2 (4).

This should be equal to

asymmetry = (ttp4/mtp4 - ttp2/mtp42/(ttp4/mtp4 + ttp2/mtp2) ,

where ttp2 (ttp4) is the true target polarization for run set 2 (4).

If we assume that ttp2 = mtp2 (i.e. set 2 has correctly measured 
polarization) and allow ttp2/mtp2 = x, then

asymmetry = (x-1)/(x+1)

Now, since the plot on slide six shows asymmetry ~ 0.1 then

0.1 = (x-1)/(x+1) ->
0.1x + 0.1 = x-1 ->
1.1 = 0.9x ->
x = 1.1/0.9 = 1.2

This would mean that the measured polarization for set 4 (with the 
assumption that set 2 has a correctly measured polarization) is off by 20% 
.

In short: In the meeting, I was wrong about what the plot represented, and 
if I am now correct in my interpretation, then Priya's plot does show a 
clear relationship for the polarization between the two runs sets, and 
that the polarization between set 2 and 4 could be wrong by about 20%.

Sorry about the long email. I just wanted to clear up any confusion I 
might have caused.

Take care,
Michael