The KTeV experiment at Fermilab gives a good opportunity to investigate the neutral cascade semi‐leptonic decays. The study of the &Ygr;0muon semi‐leptonic decay, &Ygr;0→ &Sgr;+&mgr;−&ngr;¯&mgr;has a theoretical motivation to understand the interplay of strong (QCD) and electro‐weak interactions. However this decay is suppressed by phase space with only 21 MeV of energy release, making it difficult to collect a large sample of decays. In the present analysis we briefly discuss the theory of the decay, the experimental apparatus of KTeV and the reconstruction steps of the &Ygr;0→ &Sgr;+&mgr;−&ngr;¯&mgr;decay. © 2003 American Institute of Physics