Attending VZ,AS,CC,CZ,AM,TA,DH,MK.
+Attempt to define official data set for next round of conferences in
April.
Either we take Dec. 31, 2004 as a natural separator of datasets, or e.g.
end of March as a deadline for the next official preliminary dataset. We
have to see how well the 2005 analysis goes in terms of calibrations and
recrunch. In both cases, the Dec 2004 hydrogen data is included in the
new dataset.
+Talking about Tavi's asymmetries that he showed three weeks ago. Had
observed systematic shift between MAID-based MC and measured asymmetries.
Is presently working on implementing MAID in combination with radiation
corrections into MC.
It is suggested that TF will present the status of this effort soon
(next week?), also in regard of the APS meeting and the collaboration
meeting in April
How does BLAST-MAID-MC compare with Aki's simulation?
+hPz systematics: in part discussed last week in AM's absence. hPz can be
extracted from quasileastic ep and en scattering, but also from elastic
ed (PK), and perhaps from inclusive, too (NM).
ep: hPz=0.52+-0.004+-0.02
en: hPz=0.54+-0.02+-0.01
I.e. the statistical error of en is about the size of the systematics in
ep. Can we evaluate the systematics of hPz using the varuious
independent channels?
At present, hPz from ep shows a Q2 dependence, a dropoff by 10-15% in Q2
from 0.1-0.4 (GeV/c)^2. VZ should provide a direct comparison of hPz
versus Q2, for the same bins and for the same dataset, in order to have a
cross check of ep and en.
Part of the Q2 "dependance" may be explained by the deviation of GEp and
GMp from the diopole form factors, however not quantitatively.
The dependance on Q2 remains even after applying kinematical corrections.
-Need to evaluate variation of hPz as a function of which correction is
used (AM's or EG's)
+Discussion on the spin angle:
The uncertainty of the spin angle is the biggest contributor to the
systematics of GEn (varies 12% per degree).
Average spin angle for ed-elastic event distribution from
CZ's analysis: 31.2+-0.5(t20),
Genya's measurement: 31.8+-1.04(RMS)(1 degree alignment error)
-Need error estimate of the TOSCA-simulated field map
-How much does the average spin angle vary with the choice of the map?
A better measurement (<0.5deg alignment error) is certainly doable and
should be persued after the run.
+Extended analysis meeting prior to the collaboration meeting:
Suggested to hold this meeting already on Wednesday 04/06/2005 instead of
Thursday. Please let me know if that's fine with everybody.
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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