The hole in Px-Py is well documented in the real data, and is clearly shown in the SUNY plot.  Ajit asked in his 29 June 2000 e-mail if this hole is reproduced in the simulations.  CP shows in one slide of his Obernai talk sept 99, that the simulator does "see" this hole, if I understand this slide correctly.  I have also tested this with the simulations that I have.  The hole appears in the positive px and small py.  To see this effect in the simulated data I made 1-D plot of (# of tracks in)/(# of tracks out) vs px.  A cut of abs(py)<0.2 was made to look in the region of the hole.  The four following plots are the result for each of the energies. The hole is clearly present.
8GeV
6GeV
4GeV
2GeV