From: Glen Warren (gwarren_at_anti-spam)
Date: 16-Jun-2003 22:05:28
GEn01 analysis meeting June 11, 2003
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attended by:
Donal, Paul, Oscar, Hongguo, Frank, Nikolai and Glen at JLab
REPORTS
*) Background: Ntuples have been generated, but Frank has no had the
time to analyze them. He is also redoing the Q2=0.5 background runs to
have a consistent set of data.
*) Stick 3 dilution factor: simulations still in progress
*) Q2=0.5 fourth pass: 20 runs shy of being complete. Had some problems
with the latest system "upgrades".
*) HMS momentum: Glen reviewed the HMS field setting codes for 98 and
01. There are archived subdirectories in the cdaq account for 99 and
01. The codes in there give the settings used in 98 and 01, i.e. the
code didn't change between 98 and 01. As we didn't apply the momentum
offset in the 98 analysis, both the 98 and 01 analysis are consistent
with no dipole offset.
*) Target Polarization: Paul tried to determine the stop and start
times of runs with a completely different program. Preliminary look at
results does not show the spike in run times discussed last week.
Before releasing a new version of the target polarization data, Paul is
waiting for the Q2=0.5 pass to be complete to get some info from the
sync filter. He expects to be done by next week.
*) Rates for dilution factor uncertainties: There was a miscommunication
about the ntuples. They are available for use.
*) Pion production: Frank's analysis shows that the asymmetry around
W=1.1 is less than 30% of the standard neutron asymmetry. We will treat
the pion production contamination as a dilution factor with a 30%
uncertainty due to asymmetry and modeling issues. Thus the correction
is 0.44% +- 0.12%.
*) vertical misalignment: the idea was raised about possible vertical
misalignment of the target, mostly the concern is the field polarization
pointing out of plane. The conclusion was that we have to rely on the
surveyor's. Donal will review the surveyors' reports.
*) Binning: There was a lot of discussion about binning and Glen's
suggestions. We agreed on the following: 1) the value for Gen will be
extracted by looking at the acceptance averaged quantities, not looking
at binning in a subset of data. 2) We will use the binning results to
define a model dependence, details yet to be determined. 3) We will
proceed with the usual kinematic uncertainties, looking at how things
vary in theta,E,E',theta_t, and ypos. This is best done in MC.
Donal
*) work on paper.
*) review surveyors reports are target alignment
Glen
*) work on paper
*) Discuss with Frank the approach to kinematic uncertainties.
Nikolai
*) Give Hongguo rates are various target materials for Q2=1
Frank
*) accidentals
Hongguo
*) dilution factor for stick 3 using path lengths thru materials.
*) kinematic uncertainties
*) dilution factor uncertainties
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