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Hoi,

no  numbers  here, just  a  few plots  to  convince  myself that  it's
worthwhile to investigate  in more detail.  All this  has not yet been
done properly, but just by looking at the ntuples with Draw(). All the
plots show something against theta. On top is data, the bottom plot is
MC. 

As already  mentioned by  Ric, there is  a non-negligible  fraction of
SVT-only tracks with high momenta:

  http://www.slac.stanford.edu/~ursl/talks/100202/momentum-svtonly.ps.gz

Looking at the theta distribution of (nearly) all tracks, 
  
  http://www.slac.stanford.edu/~ursl/talks/100202/theta-all.ps.gz

you can 'clearly'  see the problem if you know where  to look. To make
it more obvious, now for SVT-only tracks with momentum <0.18 GeV:

  theta:     http://www.slac.stanford.edu/~ursl/talks/100202/svt-only.ps.gz
  dcaz:      http://www.slac.stanford.edu/~ursl/talks/100202/dcazPrimVtx.ps.gz
  chi2/ndof: http://www.slac.stanford.edu/~ursl/talks/100202/chi2-ndof.ps.gz

I don't know how to interpret the last plot, but the band at theta=1.5
going down to 0 is from Svt-only tracks.

If you require at least one DCH hist, all looks fine: 

    http://www.slac.stanford.edu/~ursl/talks/100202/with-dch.ps.gz

I think it's time for a serious  study, and I'll do that over the next
few days. It might affect a few things, though. 


Cheers, 
--U.