mass difference

As a more stringent test we have studied physics processes involving mass reconstruction using algorithms and code that are presently used in CLEO II. Ten thousand events with the decay followed by were generated isotropically in . In Fig. we show the mass difference, , as a function of momentum. A cut on this mass difference is a common method used to tag 's in the CLEO II detector. Over the entire momentum range the new detector is comparable or better than CLEO II. This can be attributed to two effects, the superior momentum resolution and the superior angular resolution of CLEO III. We note that the CLEO III detector reaches = 0.7 MeV/c at GeV/c and by more appropriate use of the silicon this might be reduced to 0.6 MeV/c.