Mike,
I built two other vector asymmetries AdV and AeV which if everything is
right should be very small (zero in PWBA, small due to FSI,MEC, etc.).
And in fact they are no more than 2% in 5 out of 6 Q^2 bins (there is
alway one bin which is due to Poisonn statistics out of this limit, but
it is still no more than 5%, above or below zero, randomly). Hence, so
far I see no evidence of anything being wrong. Also, quasi-elastic
channel points to a lower Pzz than reported by Genye and Chi. However,
the error due to the statistics is still rather large and we never
established the error in Pzz from d(e,e'p)n tensor asymmetry due to theory.
Cheers, Vitaliy
Michael Kohl wrote:
>Could you all check the yields for each spin state separately? If we were
>missing a bit e.g., this could be a source for both a false asymmetry and
>for a big polarization.
>
>Michael
>
>
>
>On Mon, 5 Jul 2004, vitaliy ziskin wrote:
>
>
>
>>Perhaps, we can resolve this by running unpol deuterium for false
>>asymmetry. Keep in mind that Pz from quasi-elastic channel also appears
>>to be large.
>>
>> Vitaliy
>>
>>
>>Chi Zhang wrote:
>>
>>
>>
>>>Hi, all
>>>
>>>I checked the data after reading Genya's email when I got back from
>>>the fire work show.
>>>
>>>Here is my fitted values for Pzz, and the atatched figure shows the fitted
>>>theory curve with the data.
>>>
>>>Take target spin angle at 32 degrees. I have:
>>>
>>>
>>>from Parallel kinematics data only: 52.3+-2.5%
>>>from Perpendicular Kinematics only: 61.4+-1.5%
>>>from difference from the two kinematics: 56.9+-1/4%
>>
>>
>>>Consider that Genya uses a model that predicts smaller T20, I think my
>>>number is "consistant" with 61.4*1.2=67.2% on his side.
>>>
>>>Note that the difference in Pzz fitted from the two kinematics can be
>>>canceled out by playing with spin angle, while the fit from the
>>>"difference" is very INSENSITIVE to spin angle. So 56.9 would be the
>>>number I report.
>>>
>>>I am not sure if 57% is still TOO high to be true. But I am much more
>>>willing to believe it than 85%. It would be a very good news if it is in
>>>fact 57%.
>>>
>>>However, if you look at the plot, you will see that at Q2>=0.25(Gev/c)^2,
>>>(the 3rd point in all three figures) data point is biased toward VERY
>>>LARGE asymetry which I believe is NOT real. Also please just ignore the
>>>4th point which contains all events passing my cuts with Q2>0.35. In one
>>>of the figure, the 4th point has no error bar which means 0 count is found
>>>in at least one of the spin states.
>>>
>>>If Pzz if fitted by integrating all data into ONE bin, we will get a very
>>>large Pzz due to the weird behavior in the 3rd bin. I think this shows the
>>>limitation of the 1-bin method to determine Pzz.
>>>
>>>I think the problem of weird Q2 evolution is likely to be in
>>>detector/software. I would like to use this as an opportunity to remind
>>>every body that our resolutions are still at 30MeV, 1deg, 2.5cm level. I
>>>do not think we will be able to move further with "PHYSICS" before we pay
>>>the price to make the dectectors work as we expected.
>>>
>>>In the end, I would like to give a short report on Wed analysis meeting,
>>>if there is one, about a program of wire chamber time to distance
>>>calibration I have been prototyping since the beginning of the summer.
>>>
>>>Chi
>>>
>>>
>>>
>>
>>
>>
>
>
>
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