[G8b_run] Polarization study part 2

[Volker Crede]

Hi Mike,

I looked over your slides, this is great work, thank you very much. I will check my polarization modification code over the weekend and compare to what you just sent out (slides 9-14).

When I did my overlap studies, I was able to qualitatively confirm your results. However, you are probably right that the single-pion reaction is the only channel which provides enough statistics to accurately do what you have done.

Best wishes,

       Volker


On Jan 13, 2012, at 7:14 PM, Michael Dugger <dugger at jlab.org> wrote:

> 
> Hi,
> 
> I have spent some time going through my code that is related to the 
> modification of the polarization values, and have created some new plots. 
> In particular, I have new comparison plots that show ratios and 
> differences of the modified polarization to the unmodified polarization. I 
> have also made some plots that serve as a sanity checks. All of these 
> plots are included in a new presentation.
> 
> Note:
> I have verified that the code I sent out on November 9th should modify 
> the polarization the same way that the polarization is modified in my 
> code.
> 
> During one of the g8b meetings, I made the comment that the 
> modification of the polarization were probably only a few percent. I came 
> to this conclusion by looking only at one edge setting and polarization 
> plane (1.9 GeV PARA). After looking more closely into the polarization 
> ratios, I discovered that the 1.9 GeV PARA set was not a fair 
> representation of the entire data set. I was wrong about the general size 
> of the modifications. I think it is accurate to state that the 
> modifications to the polarization are typically less than 10% but can be 
> larger.
> 
> Because no one else has the statistics that the pi0 channel affords me, it 
> is easiest for others to compare the changes in the polarization to my 
> plots, to check that the modification code yields similar results to mine.
> 
> Of course, it would be best if someone could verify that the 
> consistency of the overlap regions conform to what I see, but I realize 
> it is difficult to obtain precise results for reaction signatures other 
> than the single pion reactions.
> 
> The new presentation can be found at:
> http://wwwold.jlab.org/Hall-B/secure/g8b/ASU/polCorrectionV2.pdf
> 
> In case you don't want to look at all the slides. Here are a few slides 
> that may be of interest:
> 
> On slide 2 I state the cuts needed to obtain the results presented.
> 
> On slide 3 I have a table showing the self consistency of the data when 
> corrections are applied, and when corrections are not applied.
> 
> On slide 8 there is a disclaimer regarding the 2.1 GeV data set.
> 
> Slides 9-14 show comparisons of the modified polarization to the original 
> polarization. These are the plots that should be used to check if your 
> polarization-modification code gives the same results as I have.
> 
> Take care,
> Michael
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