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
> >
>
>
>
--+-------------------------------------+--------------------------+ | Office: | Home: | |-------------------------------------|--------------------------| | Dr. Michael Kohl | Michael Kohl | | Laboratory for Nuclear Science | 5 Ibbetson Street | | MIT-Bates Linear Accelerator Center | Somerville, MA 02143 | | Middleton, MA 01949 | U.S.A. | | U.S.A. | | | - - - - - - - - - - - - | - - - - - - - - -| | Email: kohlm@mit.edu | K.Michael.Kohl@gmx.de | | Work: +1-617-253-9207 | Home: +1-617-629-3147 | | Fax: +1-617-253-9599 | Mobile: +1-978-580-4190 | | http://blast.lns.mit.edu | | +-------------------------------------+--------------------------+
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