[Frost] Comparing fsu-EC with cmu-EC

[Bill Briscoe]

Hi,

I don't usually weigh in on these things, but I agree with Mike here. The
Carbon target is for background purposes only, let's focus on the reactions
of interest that we can constrain. 

Bill

PS  -- We have just completed the background carbon measurement at Mainz,
which we do in separate runs. 



-----Original Message-----
From: frost-bounces at jlab.org [mailto:frost-bounces at jlab.org] On Behalf Of
Michael Dugger
Sent: Tuesday, August 31, 2010 12:00 AM
To: Sungkyun Park
Cc: FROST
Subject: Re: [Frost] Comparing fsu-EC with cmu-EC


Hi,

It does not make any sense to show the energy correction for the Carbon
target when the assumed reaction is "gamma p -> p pi+ pi-". We should
probably stop showing these energy corrections for Carbon. It is misleading

There is no over-determined reaction that we can look at for the Carbon
target. There will always be some nuclei recoil that is not seen. For this
reason, there is not enough information to completely determine the momentum
and energy corrections for the Carbon target.

The only value of the Carbon target is for subtraction purposes. We will
have to assume that the energy and momentum corrections for Carbon are
derivable from the other targets. Most likely, the energy/momentum
corrections for CH2 will be used for the Carbon.

The current situation is that FSU and CMU are in large disagreement. The ASU
results match more closely with the CMU corrections. The only thing that I
know for sure is that something is wrong with at least one tagger-correction
analysis :(

-Michael

On Mon, 30 Aug 2010, Sungkyun Park wrote:

> Hi,
>
> I make plots to compare fsu EC with cmu EC in the following web:
>    
> http://hadron.physics.fsu.edu/~skpark/research/research_aug3010.html
>
> fsu EC means that I applied Michale's tagger correction and Sung's energy
correction together.
> * The red points are the fsu EC.
> * The blue points are cmu EC.
>
> The unit of the Y axis is GeV.
> In the x axis, there are three kinds of version;  E(mea. photon)/ 
> 2.478 , Z-Vertex [cm],and phi [degree]
>
> I did not subtract the carbon influence from the butanol and ch2 target.
> I will update plots to remove the carbon influence soon.
>
> Sung
> Florida State University
>
>
>
>
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