[d2n-analysis-talk] BB tracks

[posik at jlab.org]

Hi all,

  As Brad suggested I am going to do a rough calculation of the H2 cross
section for our 1-pass runs. I am currently replaying these runs now so
that both BigBite and LHRS variable are included in the output
ROOTfiles. While waiting for them to finish, I took a look at one of the
H2 runs that had only a few events and finished before the rest, run
1259.

What I did was the following:

First I plotted just BB.tr.n with no cuts, I just replayed the 1259.dat
file with an empty .cdef file, so there are absolutely no cuts at all on
that plot (left plot).

Next I plotted BB.tr.n with a T5 (our coin trigger) cut and compared how
many tracks I had on the T5 cut plot to the first plot. For the H2 run
this was ~6% (middle plot).

Finally I plotted BB.tr.n with a T5 && BB.tr.n==1 cut and compared how
many of the tracks with the T5 cut were one tracks. For the H2 run this
was ~82%
(right plot)

I then repeated this for runs 1203 (3He 1-pass 4uA) and 2060 (3He 4-pass
13uA)

If I am understanding this correctly, the track % of interest is the one
that says how many one tracks there are in the trigger cut plot (ie
comparing my middle and right plots)?

Thanks
Matt
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