Re: A note on mass resolutions in GlueX/HallD

[Prof Paul Eugenio <eugenio@fsu.edu>]

Hall D PID Mail List:


I smeared using David's new resolution functions.


On Sat, 2008-03-15 at 15:26 -0400, Alex Dzierba wrote:
> Sorry for not asking this earlier - when you say "smeared using the new
> functions" are you referring to Mark's functions?
> 
> At 1:02 PM -0400 3/15/08, Prof Paul Eugenio wrote:
> >Hi Alex,
> >
> >Last night I ran some 3pi generated event through the new smearing
> >functions.  The events were generated with e^-5t distribution, and
> >weighted with Adam's 3pi cross section what we used in the blind PWA
> >studies.  I subjected these events to fiducial cuts where events were
> >accepted if  0.150 GeV < p_pion < 7 GeV and  1 deg < theta_pion < 140
> >deg.   These events were then smeared using the new functions.  I found
> >that the new routine return unsmeared momenta above 7GeV so I cut these
> >out.  I also smeared the beam by an expected(RTJ) 0.06% (0.02%
> >accelerator + 0.04% tagger).
> >
> >I have attached 3 figures.  The file 3pi_newSmear.pdf shows the t, 3pi,
> >2 PiPlus, 2pi, mmsq, and cos_GJ.   A fit to the mmsq over the same range
> >as in your report results in a sigma of 0.27 GeV^2 (chisq/dof = 3.7).
> >This is in good agreement with your result (0.33 GeV^2) and shows a
> >slight improvement as expected. 
> >
> >In your report you compared to an e852 sigma of 0.31 GeV^2. I came
> >across a different published E852 mmsq sigma result.  In Phys. Rev. D65
> >072001, the mmsq has a sigma of 0.26 GeV^2(I have attached a clip from
> >the paper in the file e852-3pi-mmsq.jpg).  Note that E852 fit was over a
> >wider range. I tried a fit over this same mmsq range.   The result was a
> >sigma of 0.30 GeV^2 but much poorer fit ( chisq/dof = 7.6 ).   See plot
> >in 3pi_new-mmsq-compare2E852.pdf.
> >
> >Paul 
> >
> >
> >--
> >--
> >Prof. Paul Eugenio
> >Department of Physics
> >Florida State University
> >Tallahassee, FL  USA
> >
> >850-644-2585
> >eugenio@fsu.edu
> >
> >Attachment converted: Macintosh HD:3pi_newSmear 1.pdf (PDF /«IC») (002A76DE)
> >Attachment converted: Macintosh HD:e852-3pi-mmsq 1.jpg (JPEG/«IC») (002A76DF)
> >Attachment converted: Macintosh 
> >HD:3pi_new-mmsq-compare2E852 1.pdf (PDF /«IC») 
> >(002A76E0)
> 
> 
-- 
--
Prof. Paul Eugenio
Department of Physics
Florida State University
Tallahassee, FL  USA

850-644-2585
eugenio@fsu.edu