[Clas_cascades] Minutes 11/3/2010

[Hovanes Egiyan]

Hi Alex,

there are  two 4-star Lambda-states there that can
couple to NK system, Lambda(1820) and Lambda(1830).
Both of them are about 80-100 MeV wide.
For the Lambda(1820) KN decay is the favorite channel.
And there are also other 3-star Lambda-states listed in PDG.

Hovanes.



On 11/05/2010 12:46 AM, Alex Kubarovsky wrote:
> Dear Zhiwen,
>
> On your plots there is prominent near 1.85 GeV, is it Lamda(1820) or 
> other Lambda with the mass in this region?
>
> Thanx, Alex.
>
> On Fri, Nov 5, 2010 at 12:02 AM, Zhiwen Zhao <zwzhao at jlab.org 
> <mailto:zwzhao at jlab.org>> wrote:
>
>     The attached files shows the nucleon MM of K0 in PrtK0Km channel
>     and Kp in PrtKpKm channel.
>     The MM is in the first column, the InvM of pkm is second, and the
>     third shows one versus the other
>     The top row is after nucleon missing mass cut, the bottom row is
>     after further cut on nucleon missing momentum at 200MeV.
>     Overall the MM plot has much worse resolution than the InvM plot
>     around Lambda1520 and the xk0 has worse resolution than xkp
>
>     Those MM plots have no "fermi correction" as I showed in the
>     meeting because I think the method I used is not good.
>
>     Zhiwen
>
>
>     On 11/04/2010 01:49 PM, Elton Smith wrote:
>
>
>         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
>         <http://www.jlab.org/%7Ezwzhao/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 <mailto:elton at jlab.org>
>         (757) 269-7625
>         (757) 269-6331 fax
>         _______________________________________________
>         Clas_cascades mailing list
>         Clas_cascades at jlab.org <mailto:Clas_cascades at jlab.org>
>         https://mailman.jlab.org/mailman/listinfo/clas_cascades
>
>
>     _______________________________________________
>     Clas_cascades mailing list
>     Clas_cascades at jlab.org <mailto:Clas_cascades at jlab.org>
>     https://mailman.jlab.org/mailman/listinfo/clas_cascades
>
>
>
> _______________________________________________
> Clas_cascades mailing list
> Clas_cascades at jlab.org
> https://mailman.jlab.org/mailman/listinfo/clas_cascades

-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://mailman.jlab.org/pipermail/clas_cascades/attachments/20101105/39a038bd/attachment.html