Dear Zhiwen, <div><br></div><div>On your plots there is prominent near 1.85 GeV, is it Lamda(1820) or other Lambda with the mass in this region?</div><div><br></div><div>Thanx, Alex.</div><br><div class="gmail_quote">On Fri, Nov 5, 2010 at 12:02 AM, Zhiwen Zhao <<a href="mailto:zwzhao@jlab.org">zwzhao@jlab.org</a>> wrote:<br>
<blockquote class="gmail_quote">The attached files shows the nucleon MM of K0 in PrtK0Km channel and Kp in PrtKpKm channel.<br>
The MM is in the first column, the InvM of pkm is second, and the third shows one versus the other<br>
The top row is after nucleon missing mass cut, the bottom row is after further cut on nucleon missing momentum at 200MeV.<br>
Overall the MM plot has much worse resolution than the InvM plot around Lambda1520 and the xk0 has worse resolution than xkp<br>
<br>
Those MM plots have no "fermi correction" as I showed in the meeting because I think the method I used is not good.<br><font color="#888888">
<br>
Zhiwen</font><div><div></div><div class="h5"><br>
<br>
On 11/04/2010 01:49 PM, Elton Smith wrote:<br>
<blockquote class="gmail_quote">
<br>
resent: Elton, Hovanes, Zhiwen, Stepan<br>
On the phone: Ralf, Kijun<br><br>
Notes by Elton.<br>
<br>
== Announcements==<br>
# No meeting next week due to the collaboration meeting.<br>
<br>
== Draft of Phi-- Paper (Hovanes) ==<br>
# Hovanes uploaded a new version a couple of days ago.<br>
# Stepan has provided comments. Elton made suggestions to the section on<br>
upper limits.<br>
# Kijun has some comments he will send in. Ralf will try to finish reading<br>
the draft today.<br>
# Ralf: Abstract mentions the Lambda pipi mass spectrum, but it is not in<br>
the paper. We discussed this and concluded that it should be taken out of<br>
the abstract but nevertheless the figure should be added to the paper. It<br>
will make it easier to explain the steps to obtaining Fig. 10.<br>
# Hovanes suggested changing the title to "upper limits for<br>
photoproduction cross section of Phi--". No strong opinions were offered.<br>
# Generally, we all need to review the title, abstract and conclusion<br>
section once the paper is close to final.<br>
<br>
== Analysis note for Lambda(1520) (Zhiwen) ==<br>
# Recoil spectra of MM(K), requested by Igor were shown for both MM(K0) in<br>
gn(p)->pK-K0(p) and also for MM(K+) in gp(n)->pK-K+(n). In both cases the<br>
Fermi momentum blurrs the Lambda peak. The invariant mass of pK- has much<br>
better resolution. In both cases a correction for the Fermi momentum is<br>
obtained by MM of all three detected particles.<br>
# Ralf: The Fermi momentum distribution is fairly accurately reproduced,<br>
so it is surprising that the resolution of the pK- invariant mass is not<br>
mostly recovered. This was discussed without final conclusion, except that<br>
it is likely that the resolution in missing momentum is poor compared to<br>
that required for computing the invariant mass. Ralf suggested that the<br>
generated Fermi momentum be smeared with expected detector resolution to<br>
see how much it changes the distribution.<br>
# [<a href="http://www.jlab.org/~zwzhao/totalXsection_high.gif">http://www.jlab.org/~zwzhao/totalXsection_high.gif</a> Total cross section<br>
for Lambda(1520)] plotted vs energy, shows a large discrepancy in the<br>
lowers energy point (1.75-2GeV). The estimated cross section is about<br>
3+/-1 micro b cross section oompared to about 0.8 microb from other data.<br>
No systematic errors are included, and no bin-centering corrections.<br>
# Suggestions on what to look for are: check the kinematic cover of the<br>
bins at high -t. Check bin-centering corrections. Consider differences of<br>
cross section measure with/without phi cut as a measure of the sytematic<br>
uncertainty.<br>
<br>
<br>
== Next Meeting Nov 18, 8:00 am ==<br>
# Phi-- Draft of paper (Hovanes)<br>
# Lambda(1520) update (Zhiwen)<br>
<br>
<br>
Elton Smith<br>
Jefferson Lab MS 12H5<br>
12000 Jefferson Ave<br>
Suite # 16<br>
Newport News, VA 23606<br>
<a href="mailto:elton@jlab.org">elton@jlab.org</a><br>
(757) 269-7625<br>
(757) 269-6331 fax<br>
_______________________________________________<br>
Clas_cascades mailing list<br>
<a href="mailto:Clas_cascades@jlab.org">Clas_cascades@jlab.org</a><br>
<a href="https://mailman.jlab.org/mailman/listinfo/clas_cascades">https://mailman.jlab.org/mailman/listinfo/clas_cascades</a><br>
</blockquote>
</div></div><br>_______________________________________________<br>
Clas_cascades mailing list<br>
<a href="mailto:Clas_cascades@jlab.org">Clas_cascades@jlab.org</a><br>
<a href="https://mailman.jlab.org/mailman/listinfo/clas_cascades">https://mailman.jlab.org/mailman/listinfo/clas_cascades</a><br></blockquote></div><br>