[d2n-analysis-talk] Methodology for Pion Corrections to Efficiencies

[David Flay]

Hey Brad,

I have been thinking about how I'm going to tackle the pion corrections we
discussed last meeting -- I didn't find much of anything in Karl's thesis
or tech notes discussing what he did... unless I'm not looking in the
right sources?

Anyway, I was thinking -- Plotting the 2D energy plot (L.prl1.e:L.prl2.e)
with the cuts I initially use to select my 'electron sample'.  Then, that
would give me my 'raw' sample number = N_i.  Then, I plot E/p subject to
the same cuts, but now differentiating between pions and electrons
(anti-Cerenkov cut, and Cerenkov > 0, respectively).  I can integrate over
these two distributions, and I obtain N_electrons + N_pions = N_i.

So, this would mean that my true electron sample is: N_i - N_pions =
N_electrons.

Then, I can plot the gas Cerenkov sum subject to the initial cuts (applied
to the 2D shower plot).  Counting the entries in this histogram, I would
then calculate:

efficiency = N_cerenkov/N_electrons

However -- I have a feeling this won't work (a quick run through just now
for p = 0.6 GeV, with no fits to the resulting histos in E/p, I got an
efficiency of 1), or may be too 'simple.'  In other words, should there be
a deconvolution of the pion curve and electron curves (in E/p) involved?

Thanks,

Dave




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David Flay
Physics Department
Temple University
Philadelphia, PA 19122

office: Barton Hall, BA319
phone: (215) 204-1331

e-mail: flay at jlab.org
            flay at temple.edu

website: http://www.jlab.org/~flay
              http://quarks.temple.edu
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