[Clas_cascades] minutes of today's meeting.

[Elton Smith]

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

== Announcements==
# Haiyun successfully defended his thesis last Friday. Congratulations!
# Haiyun has accepted a post-doc position at CMU (Reihard)
# Zhiwen has accepted a post-doc position at UVa (working on parity
violation)

== Comments on Phi-- Note ==
# Hovanes has made updates to the response to the committee including some
figures
# Latest response includes figures for the ctau of the Lambda and the
Cascade.
#* Lambda ctau~7.6 cm (full range) and ctau~8.2 cm (tail) and ctau-7.89 cm
(PDG). Hovanes: The resolution is assume constant, but certainly depends
on kinematics so will affect the fitted quantities.
#* Xi ctau=3.9 cm (full) 4.3 cm (tail) and 4.9 cm (PDG). The Xi is highly
contaminated with combinatorial background.
# Items were listed that need completion:
#* No. 9 and 11 need figues
#* No. 13 asks about decays outside the start counter. At the moment the
analysis does not require hits in the ST, which the trigger does. Hovanes
can use the simulation to evaluate the faction of events that did not
trigger because they decay outside the counter.
#* No. 16 needs figure
#* No. 25 see answers to normalization note. (done).
#* No. 28. Elton has text from previous iteration. (done).

== Comments on Normalization Note ==
# Lewis: Working on subtraction correction from higher lying resonances.
# Elton: Last week we agreed that the eg3/g11 comparison will be completed
with the 2g correction, but not the additional subtraction, so that we can
compare directly to previous documentation, as well as respond to the
committee. As long as both samples are treated in the same way, the
comparison should be valid.
# Elton: Suggested to separate the file for Phi-- and Normalization, so
that the groups can work independently.
#* Completed: The new (normalization) file is
docs/eg3/anotePhi1860/comments/SecondRoundComments_Normalization.tex. The
Phi-- reply remains in SecondRoundComments.tex. The new files are now
checked in.

== gn -> K+Sigma*-(1385) ==
# [[KSigma update May 5 2010]]: Haiyun
# gn -> K+Sigma*-, Sigma*- -> Lambda pi-, Lambda -> p pi-. Final state is
K+ p pi- pi-.
#* Particles identified, Lambda selected as best p pi-.
#* Eliminate K*0 contribution.
#* Select exclusive by cutting on neutron in missing mass of K+ppi-pi-
spectrum.
#* Extract yield of peak in Lambdapi- spectrum. Side-bands of missing mass
spectra is subtracted.
#* Yield obtained in bins of costhe and Eg.
#* Cross section vs energy obtained and compared favorably with previous
data, except for low energy point in some spectra.
#* Costhe cm distribution used to determine the ratio of 3/2 vs 1/2
substate. K exchange contributes only to 1/2, K* can contribute to both.
The measured large fraction of 3/2 substate points to large K*
contribution. This is different than what was obtained by Guo for Sigma*0
decays.
#* Ralf: There are arguments that in a diquark model K* contributes to 3/2
only. [Ralf can you check this statement??]


== Next Meeting May 13, 9:00 am ==
# Complete comparison of eg3/g11 with 2g corrections, but no high level
resonance subtraction.
# Phi-- response to committee
# Normalization note (USC)
# Haiyun post plots of angular distribution to wiki


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