Richard,
A couple of points:
(1) Thus far the only errors that are included are statistical. The
systematic errors due to uncertainty in the q-angle and target
spin angle are not yet included, but Adrian, Tong, and I have
discussed them (just yesterday afternoon).
(2) The effect of the "dilution factor" should already be included
because it will determine the error on the asymmetries. If the
product of beam and target polarization is small, then the
observed asymmetry will be small and the relative error in the
asymmetry will be large with the same statistics. In the super
ratio, which is used to extract GE/GM, the dilution factor itself
cancels out, but the relative error on the asymmetries in the
numerator and denominator propogate through.
(3) That said, we do need to thoroughly understand the error analysis
and add in the systematic errors.
But I think Adrian's analysis shows we are getting closer. The good
news was that GE/GM came out about right at the lowest Q^2. What we
don't yet understand is the fairly rapid decrease with increasing Q^2.
John
On Wed, 31 Mar 2004, Richard Milner wrote:
>
> Hi Adrian,
> Thanks for your message. I am looking forward to your presentation. My
> point is that you should do a sanity check on the error bars using the
> known `dilution factor' and total number of ep events and compare with the
> proposal. The bottom line is to check that your results make sense. This
> is important for extrapolating to future running.
> Thanks,
> Richard
>
>
> On Tue, 30 Mar 2004, Adrian T Sindile wrote:
>
> > Hi, Richard!
> > I do not trust the error calculation at this point (I wrote that code
> > while on shift on Monday) - and GE/GM drops off much faster than
> > expected... then goes back up.
> > I was excited about actually getting to the point of extracting GE/GM, not
> > because I was confident in the result...
> >
> > I know I get the super-ratio versus Q2 correctly (and I trust the error
> > calculation for that). I am looking into this and hope to be able to say
> > more on Thursday...
> >
> > Adrian
> >
> > -------------------------------
> > Adrian Sindile
> > Research Assistant
> > Nuclear Physics Group
> > University of New Hampshire
> > phone: (603)862-1691
> > FAX: (603)862-2998
> > email: asindile@alberti.unh.edu
> > http://einstein.unh.edu/~adrian/
> >
> >
>
>
-- 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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