Chi,
Very nice!
The larger error bars near 3 fm-1 are also seen in Dave Abbott's
analysis. The fact that it correlates to where T20 is at it's negative
maximum (and near the theoretical limit) probably means that the data
are less sensitive the the values of GC and GQ in that region.
John
On Thu, 8 Sep 2005, Chi Zhang wrote:
>
>
> Hi all
>
> I would like to share some new results from BLAST ed elastic, the GC and
> GQ obtained from tensor asymmetries measured at BLAST. see the atatched
> figure. If people want to show this PRELIMINARY result in their conference
> talks, I will provide plots in required format.
>
> Here is some detail about the result:
>
> Abbott 1 is refitted with BLAST tensor and vector results. BLAST Asymmetry
> data and A(Q) interpolated using the Abbott fit are fitted at each Q2
> point by varying GC and GQ. A(Q) is obtained from the above Abbott 1 fit.
> B(Q)(or GM(Q)) are also fixed by the above Abbott 1 fit. All systematic
> errors are included in the fit. As expected, I was not able to obtain good
> results varying GM at the same time.
>
> Preliminaryly, BLAST data confirms the first node of GC at
> 4.172+-0.042 fm-1 compared to 4.21+-0.08 fm-1 obtained from data up to
> JLAB 2000, and in agreement with VEPP-3 2003 PRL value. VEPP-2 2003 PRL
> listed first node at 4.173+-0.038fm-1. the seeminly smaller error they
> quoted could be due to the fact that they fitted Abbott 1 by only varying
> the first node position leaving all other 17 parameters fixed while I did a
> full 18 parameter fit.
>
> The error bars in GC and GQ reaches a largest value at arround 3 fm-1 and
> then shrink down again going to higher Q values. I do not fully understand
> this behavior yet. But this trend in error size is also seen in VEPP-3
> results, so I think it is a "feature" not a bug. :)
>
> Enjoy.
>
> Chi
-- John R. Calarco Dept. of Physics Univ. of New Hampshire Durham, NH 03824 phone: (603)862-2088 FAX: (603)862-2998 email: calarco@unh.edu
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