Vitaliy et al,
The projections for GEn from the original proposal have been checked
numerous times and, within the assumptions made, are realistic up to to
at least Q^2 of 0.35 where we run out of Cerenkov detector. For 1000
hours of running at design figure-of-merit (and we are running at least
equal to that right now), i.e. for about 300 kC of data, we should get
uncertainties at the lowest three points of about 7% of the Galster fit.
I think the first two bins in the recent (very preliminary) results from
Vitaliy support this. I do not understand the very large increase in the
uncertainty in the third bin of Vitaliy's preliminary results.
In conclusion, the proposal projections stand and should be modified only
with respect to the real detector acceptance we now have.
Let's try to sort this out in the next day or so.
Richard
On Tue, 20 Jul 2004, Vitaliy Ziskin wrote:
> John,
> I redid some of the fits plus I scaled my present errobars to come up
> with the prjections to the end of the run period. I scaled it by the
> propose amount of charge we are going to collect by november. I also,
> took liberty to scale it by a "fudge" factor. This factor is not big
> (1.22) and it reflects the fact that the data I'm using currently was
> run at times in unfavorable conditions for neutron detection. The
> conditions have since improved and thus the factor. It also reflects a
> slighly higher polarization of current running as compared to the data
> I'm using right now. The first two plots are the same as before only
> with little more data improved cuts. The next two plots are the same
> plots as projections. I made the data points to be perfectly on Galster
> curve for ease of fitting. Chi^2 fit looks good for that reason. So
> the errors, might be to optimistic since I'm willing to be that our data
> is not going to look this perfect. It's hard to quantify how what
> bearing this "imperfection" has on the error bar though. So my GeN plot
> includes best case scenario for first 3 data points. In the light of
> these next 3 points look somewhat too high. I will try to work that
> rest of the time to make any kind of statement about higher Q^2 points.
> The last question is the third Q^2 point. Why is it so low? I'm
> looking into this. But it would be nice to get some idea about background.
>
> Cheers, Vitaliy
>
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