[Halld-tagger] question about multiple hits in Nathan's analysis

[Daniel Sober]

After a long vacation break I am getting back to my tagger Monte Carlo
calculations.  I have no new results yet, but would like to point out
something significant about the multiple TAGH hits in the data which Nathan
presented today:

Nathan sees an enhancement over randoms in double hits for counter number
differences as large as 15,  while my simulations, including beam
distribution, bremsstrahlung angular distribution, and multiple scattering
in the exit window and the counters, show NO coincidences between TAGH
counters whose numbers differ by more than 1.  I doubt that multiple
scattering in the plastic tubes can cause such a large effect -- it will be
very interesting to see whether their removal will make a big difference.

In particular, in Nathan's Slide 8,  differences d=2 and d=3 include
coincidences between counters in the SAME PLANE.  If this is due to
scattering in a counter (or plastic tube), the angles involved must be
huge, of order 20 degrees.

Nathan:  could you break out the data for multiple hits to look for
*coincidences
between counters in the same plane*?  If these are appreciable, then we
need to think hard about where these events come from.

Dan
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