  Results from the KTeV experiment at Fermilab using neutral Xi hyperons are
presented, especially the first form-factor (FF) measurement from its
semi-leptonic decay. This decay, which is an important test of the Standard
Model, was observed for the first time using the 1997 KTeV experiment. We also
report on the analysis of a large samples of neutral Xi weak radiative decays,
and a search for the decay of a lightly bound $H^0$ dibaryon.
