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Re: Fwd: Kfit with timing



Hi Eugene,

   I've uploaded a summary talk to the portal, GlueX-1009. This talk summarizes what I've done on these PID studies involving pi/K separation. I've also uploaded the source file with all the figures in case you want to include any of them.
 
   There's a lot of information there, so I leave it to your discretion what you want to use. But I wanted to make sure there is enough background for you to be able to answer any questions you may or may not get at the review.

   Some of this may answer a question Alex raised in an earlier email this morning regarding using the kinematic fitter for PID.

Matt


On Fri, Mar 21, 2008 at 10:47 AM, Eugene Chudakov <gen@jlab.org> wrote:
Matt,

I am going to include a slide on the kinem. fitting with the something
like:
- 3-C fit improves the track resolutions
- kin. fitting allows a considerable improvement in identification of
 events with kaons over simple kin. constraints.
- the results depend on prominance of backrounds which are flat
 or non-Gaussian in the residual space.
- in the ideal case a strong possible suppression can been obtained
- the work is in progress

You may send me a few statements (items) you would like to make.
Also, you may include a plot. Will you do it?

Yesterday, I tried the 3-C fit, using the event 3-momentum. It gave me some additional
BG reduction, a factor of 2 perhaps, with simple cuts and without
a signal suppression. I will look further into it.

BTW, what improvement in track momentum resolution did you obtain with the
3-momentum fit? For p2K3pi events I get on average 2.4%-->2.0% - not that much.
I assumed the diagonal covariance matrix for p,theta,phi.
The energy residual becomes very narrow for "true" events,
so adding the 4-th fit should not change the track resolution.


------------------------------------------------------
Eugene Chudakov
http://www.jlab.org/~gen
phone (757) 269 6959  fax (757) 269 5703
Thomas Jefferson National Accelerator Facility
12000 Jefferson Ave, Newport News, VA 23606 USA





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Matt Bellis
Carnegie Mellon University
(office) 412-268-6949
(cell) 412-310-4586
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