Hi,
Attached is a plot of what I showed in yesterday's meeting with the
Friedrich and Walcher curve corrected. Since part of our discussion
centered around the sizable error in the term corresponding to the
location of the bump in GEp, I added/subtracted this error to generate two
addtional curves. The curve with a positive uGEp/GMp ratio in the region
~0.3 GeV^2 is from is with it error added, the one that continuously falls
off is from the error subtracted.
Regards,
Adam
On Wed, 30 Aug 2006, Michael Kohl wrote:
> Hi,
>
> below are the minutes of today's analysis meeting.
> The next meeting will be on Wednesday September 6, 2006 at 13:30 at Bates.
>
> Minutes:
>
> -Status ffr paper
> +Text has been reviewed.
> +Figures still being updated, asymmetry plot has been updated.
> +Chris showing plots of GE and GM. World data should really be
> original published values for GE and GM from experiments that have
> really performed Rosenbluth separation on actual measurements (not
> global fit of other data)
> +Some authors combine their cross section measurements with existing
> measurements to perform Rosenbluth separation. For this letter,
> really only experiments from which a single-expperiment extraction is
> possible should be plotted.
> +Yet another discussion on how to extract the form factors GE and GM
> from the BLAST ratio measurement combined with previous cross
> section data. Fit versus equation solving. Discussion about nature
> of cross section error when using parameterization, statistical
> versus systematic. Although the error of the cross section has
> a statistical and systematic component, for the purpose of using it
> with the the BLAST ratio measurement to deduce the separate form
> factors from solving the equations, the character of the total cross
> section error becomes systematic (no fitting involved). However, in a
> fit method where GE and GM result from a fit to the ratio and the cross
> section values, it only works if the cross section error is treated as
> point-by-point statistically independent and statistical in its nature.
> And this exactly causes problems here when using a parametrization
> because the statistical fluctuation is replaced by an error band.
> +Will sort things out in offline phone meeting tomorrow at 4pm. Will
> use the Bates conference line +1-866-867-8301, passcode 4073393
>
> -d(e,e'p)
> +hPz still Q2 dependent (~10% from lowest to highest bin). Possible
> origins: Diluted data sample (->check cuts); Resolution effects
> (->study effect of convoluting angles and momenta with finite
> resolution on asymmetry by varying resolution); or polarization
> profile along z corresponding to Q2 profile through correlation of
> z and Q2 (unlikely)
> +need to compare asymmetries and hPz vs z with MC with and without
> accounting for spin angle profile. Remaining variation of hPz with z
> could be due to polarization profile.
> +proton ff ratio from quasielastic d(e,e'p) at low pmiss (see plot in
> meeting directory) from super ratio. Ratio data from deuterium
> slightly below hydrogen data.
> +Friedrich/Walcher parameterization showing bump even for the ratio,
> in fact parameter Q_b for the location of bump is much smaller for GEp
> (0.07) than for GMp (0.35), therefore bumps in GEp and GMp seem not to
> cancel. However, Fig.3 in F.-W.'s paper shows bump at 0.2-0.3 GeV for
> all form factors. Something wrong in the Friedrich/Walcher paper? One
> should verify the fit to the data, like Chris did for Arrington's
> parameterization.
>
> -Comparison of MC for different radiative generators
> +3 radiative generators available: Mascarad-dgen (Vitaliy), pionmc
> (Aki) and ElRadGen (Tavi+Sasha)
> +still bugs in implementation of ElRadGen, need more time
> +ElRadGen still unpolarize only
> +need to compare W spectra at generator level
>
>
> Best regards,
>
> Michael
>
>
>
> +-------------------------------------+--------------------------+
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