[Clas_cascades] Minutes 11/3/2010

[Elton Smith]

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

== Announcements==
# No meeting next week due to the collaboration meeting.

== Draft of Phi-- Paper (Hovanes) ==
# Hovanes uploaded a new version a couple of days ago.
# Stepan has provided comments. Elton made suggestions to the section on
upper limits.
# Kijun has some comments he will send in. Ralf will try to finish reading
the draft today.
# Ralf: Abstract mentions the Lambda pipi mass spectrum, but it is not in
the paper. We discussed this and concluded that it should be taken out of
the abstract but nevertheless the figure should be added to the paper. It
will make it easier to explain the steps to obtaining Fig. 10.
# Hovanes suggested changing the title to  "upper limits for
photoproduction cross section of Phi--". No strong opinions were offered.
# Generally, we all need to review the title, abstract and conclusion
section once the paper is close to final.

== Analysis note for Lambda(1520) (Zhiwen) ==
# Recoil spectra of MM(K), requested by Igor were shown for both MM(K0) in
gn(p)->pK-K0(p) and also for MM(K+) in gp(n)->pK-K+(n). In both cases the
Fermi momentum blurrs the Lambda peak. The invariant mass of pK- has much
better resolution. In both cases a correction for the Fermi momentum is
obtained by MM of all three detected particles.
# Ralf: The Fermi momentum distribution is fairly accurately reproduced,
so it is surprising that the resolution of the pK- invariant mass is not
mostly recovered. This was discussed without final conclusion, except that
it is likely that the resolution in missing momentum is poor compared to
that required for computing the invariant mass. Ralf suggested that the
generated Fermi momentum be smeared with expected detector resolution to
see how much it changes the distribution.
# [http://www.jlab.org/~zwzhao/totalXsection_high.gif Total cross section
for Lambda(1520)] plotted vs energy, shows a large discrepancy in the
lowers energy point (1.75-2GeV). The estimated cross section is about
3+/-1 micro b cross section oompared to about 0.8 microb from other data.
No systematic errors are included, and no bin-centering corrections.
# Suggestions on what to look for are: check the kinematic cover of the
bins at high -t. Check bin-centering corrections. Consider differences of
cross section measure with/without phi cut as a measure of the sytematic
uncertainty.


== Next Meeting Nov 18, 8:00 am ==
# Phi-- Draft of paper (Hovanes)
# Lambda(1520) update (Zhiwen)


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