Hi Pete,
it is a very good piece of news. I hope we will make more progress in PID
calibration since other fronts of software are getting into shape.
Chi
On Tue, 20 Jan 2004, Peter Karpius wrote:
> Hi Chi-
>
> Well maybe these plots are not impressive but I am still working
> in a rough draft way just to get mass cuts. Anyway, I have skimmed some
> D2 runs with the cuts:
>
> -3 different tofs must fire (i.e. have good tdc)
> -must have at least 3 tracks all w/chi^2 < 1
> -must have at least two positive tracks in different groups
>
> with these cuts I crunched about 7 runs at 500K each and retained about 70
> events per run. I played with the binning and in two of the plots you can
> see the proton, pion, and electron peak. I then rebinned again and found
> that the proton peak became more defined while the pions and the electrons
> merged. Anyway, it seems to work quite nicely. I am glad I tried to do
> things myself (i.e. create my own mass function) though as it gave me a
> great appreciation for what you have
> done. (Good Job, I will use your function!) Anyway, thanks. Based on
> these plots, I will choose to record events with the above cuts plus:
>
> - 2 independent positive tracks with (0.6 GeV < mass < 1.2 GeV)
> - at least 1 negative track with:
> (0.05 GeV < mass < .35 GeV) for pions
> (mass < 0.05 GeV) for electrons
>
> Then I will place these into groups of either:
>
> 1: p, p, pi-
> 2: p, p, e-
> 3: p, e-, pi-
>
> as we will very likely lose either the e-, p, or pi- in our minute
> coverage which is but a fraction of 4*Pi.
>
>
> Pete
>
>
> ----------------------------------------------
> Pete Karpius
> Graduate Research Assistant
> Nuclear Physics Group
> University of New Hampshire
> phone: (603)862-1220
> FAX: (603)862-2998
> email: karpiusp@einstein.unh.edu
> http://pubpages.unh.edu/~pkarpius/homepage.htm
> ----------------------------------------------
>
> ---------- Forwarded message ----------
> Date: Tue, 20 Jan 2004 11:25:41 -0500 (EST)
> From: Peter Karpius <karpiusp@einstein.unh.edu>
> To: jrc@physics.unh.edu
> Cc: calarco@unh.edu, tong@lns.mit.edu, asindile@cisunix.unh.edu
> Subject: mass
>
> Hi John-
>
> I have started using a function called Mass() that Chi uses in
> PID. I have included this in my code and run it on about seven runs at
> 500K events each. Attached are mass plots. It seems that one can resolve
> the proton and pion peak. In one plot I have changed the binning which
> better defines the proton peak but merges the pions with the electrons.
> I am wondering if I can now make mass cuts based on these plots. For
> instance, only record events with:
>
> - 2 independent positive tracks with (0.6 GeV < mass < 1.2 GeV)
> - at least 1 negative track with:
> (0.05 GeV < mass < .35 GeV) for pions
> (mass < 0.05 GeV) for electrons
>
> -are these cuts too loose?
>
> Also, if I am not mistaken, I believe that this mass function still must make
> an assumption on the first particle mass and uses this to get vertex time
> (TOF).
> Please take a look at these plots and tell me what you think.
>
> Thanks-
> Pete
>
> ----------------------------------------------
> Pete Karpius
> Graduate Research Assistant
> Nuclear Physics Group
> University of New Hampshire
> phone: (603)862-1220
> FAX: (603)862-2998
> email: karpiusp@einstein.unh.edu
> http://pubpages.unh.edu/~pkarpius/homepage.htm
> ----------------------------------------------
>
>
>
>
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