CP Violation in Hyperon and Charged Kaon Decays

The primary purpose of the HyperCP experiment at Fermilab is to test CP in hyperon decays by comparing the decay distributions for Ⅺ− (“cascade”) decays in the decay sequence: Ⅺ− → π− + Λ0, Λ0 → π− + p, with those for the antiparticle Ⅺ+. In addition, we can test CP in charged kaon decays by comparing the slopes of the Dalitz plot for Κ+ and Κ− decays. We are also looking at rare decay modes of charged kaons and hyperons, particularly those involving muons. In two runs in 1997 and 1999, we collected approx. 500 millon charged kaon decays, 2.5 billion Ⅺ− and Ⅺ+ decays, and 19 million Ω− and Ω+ decays. This is the largest sample of fully reconstructed particle decays ever collected.