**Figure 9:**
Azimuthal angular distributions measured for 6< *r* < 7cm at *z*=+1m
for vertical displacements of =(solid line), (dotted line)
compared with the nominal one (solid circles). The distributions are
normalized by the total number of particles.

When two beams collide with a finite vertical
displacement() comparable to , we expect a
vertical, *i.e.* up-down, asymmetry in the azimuthal angular
distribution. In the simulation beam-1 and beam-2 are initially
shifted by and , respectively. We
examined the two cases of and , and plotted the angular distribution in
Fig.9. (The luminosity losses are 6 and 30% for
and ,
respectively.) Apparently, during a collision the particles are
deflected more in the upper side of the electromagnetic field of
beam-2, since they are created in the overlapping region between two
beams. Therefore, they are deflected more in +*y and less in - y
than in the nominal case, as can be clearly seen in
Fig.9. The ratios are found to be 0.76 and
0.62 for =0.5 and
1, respectively.
*

*
*

Sat Dec 21 00:34:16 JST 1996