[Clas_cascades] notes phone conference 9/30

[Elton Smith]

Present: Kijun, Elton
On the phone: Haiyun, Zhiwen  <br>
Notes by Elton.

== [[Update 8-26 | Normalization studies]] (Lewis) ==
# [[Update 9-30]] shows how new normalization comparisons are proposed.
The idea is make a global fit to a 2nd order polynomial. Fix the slope and
curvature parameters, then refit individual data sets, then compare the
constant term.
#* Elton: Notes that this should be equivalent to plotting the differences
(or ratios) of individual data points relative the global fit.
#* Kijun: He had done this already and this gave large numbers compared to
the 4.5/4.7 factors.
#* Checking the plots on Kijun's page (bottom plot of page #70), the
differences between the "4.5" and "4.7" data sets is about 20%. This needs
to be investigated.
# New draft: Elton proposed to go ahead and send out a new version of the
normalization note, with the caveat that final numbers may change. That
way others can provide comments to the draft. In parallel, Lewis can work
with Ralf to get final normalization factors for the table in the note.

==
[http://www.jlab.org/Hall-B/secure/e1-6/parkkj/g11_analysis/report/09302009.html
T-counter study for g11] (Kijun) ==
# Kijun noted that in his g11 pi+pi- cross section the data at 4.4 is low
comparared to neighboring points. The CMU analysis by Mike Williams also
shows a problem at 3.5 GeV for the different electron energy. Both points
correspond to T9.
# Kijun investigated further and could not find problems with the
T-counter calibration. However, Haiyun pointed out that this is a problem
where the photons seem to be good photons but with shifted times. It is
unclear if this is a hardware problem (likely) or could be corrected
through calibration.
# Zhiwen: The best way to verify this problem is to look at Haiyun's 2D
plot of photon time vs (photon time - vertex time).
# Elton: For the present analysis, we should eliminate this point from the
g11 data set and use the data with the excluded point for the global fits.


== Next Meeting, Wed Oct 7 ==
# Feedback on normalization note to Lewis
# Hovanes to update Phi-- note to eliminate poorly performing T-counters


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