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
+-------------------------------------+--------------------------+
| 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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