[Clas_cascades] Notes from phone conference Aug 6

[Elton Smith]

Online: Elton, Kijun, Hovanes, Stepan, Zhiwen, Ralf, Haiyun, Lewis  <br>
Notes by Elton. <br>

# Announcements: Elton will be away next week. Hovanes will run the
meeting.
# [[Update 7-30]] (Lewis) and
[http://www.jlab.org/Hall-B/secure/e1-6/parkkj/g11_analysis/report/07312009.html
g11 comparison] (Kijun)
## Good Progress on normalization issues
## Studied the differences between global trigger inefficiency
normalization and run by run. Good consistency between the two (note that
on the plot a point for run-by-run is missing and all other points should
be shifted to the right by one).
## Ratio of eg3 to cross section average is about 8%.
## Stepan: should be different systematics between triggered and
untriggered region
## Discussion of how to best extract a systematic error:
## Hovanes: suggest to use untriggered region only (because g11 has good
statistics there) and extend (with additional error into triggered region)
## Stepan: use incremental ratios starting in untriggered region and
extend into triggered region
## Suggestion: Project ratios of cross sections (triggere and untriggered
regions separately) and trigger efficiency plots (before and after Xmas
separately) onto y axis and get widths.
# [[KSigma update August 6 2009]] (Haiyun)
## time vs T-counter number
## Plots shown for "normal" T-7. One peak in time distribution
## Plots for abnormal T=9 and T=11 show two peaks.
## Plot of data for triggered events with these counters shows that
considerable events are lost due to selection cuts
## Stepan: suggestion to plot time for these counters vs. run number
## Ralf: problem could be due to one pmt from each counter acting up
## Elton: Skims that make tight timing cuts could have lost these events
at an early stage. (Not the case for the lambda skim).
## Stepan: Reason for problem is not important. If each run has a single
peak, this can be corrected, otherwise not. Hovanes indicated that if the
issue was simply run dependent, it should have already been calibrated out
because the tagger corrections were applied run-by-run.
# Phi-- (Hovanes)
## Posted the analysis note officially, it has number CLAS-ANALYSIS
2009-104. It will need to be updated with the latest normalization plots
and references.

List of items for next meeting:
# Suggestion: Project ratios of cross sections (triggere and untriggered
regions separately) and trigger efficiency plots (before and after Xmas
separately) onto y axis and get widths.


Elton Smith
Jefferson Lab MS 12H5
12000 Jefferson Ave
Suite # 16
Newport News, VA 23606
elton at jlab.org
(757) 269-7625
(757) 269-6331 fax