Observation of the Ξ0→Σ+μ−ν¯μ Decay

The KTeV experiment at Fermilab provides a good opportunity to investigate the neutral cascade semi-leptonic decays. The Ξ0 muon semi-leptonic decay, Ξ0→Σ+μ−ν¯μ, is suppressed by phase space with only 21 MeV of release energy, making it difficult to be investigated. The study of this decay has a theoretical motivation since it provides another instance to test the Standard Model of particle physics. In this analysis we have observed the Ξ0→Σ+μ−ν¯μ decay and measured its Branching Ratio using Ξ0→Λπ0 decay as the normalization mode.