Search for CP violation in Ξ and A hyperon decays: Status of the HyperCP experiment

HyperCP (E871), a Fermilab experiment searching for CP violation in Ξ and A hyperon decays, finished its first data taking run at the end of 1997, and accumulated over one billion Ξ − and ¯Ξ + decays. A sensitivity of approximately 2×10 −4 in A ΞΛ (αΞαΛ - α¯Ξα¯Λ)/(αΞαΛ + α¯Ξα¯Λ) is expected. A non-zero value of A ΞΛ would be unambiguous evidence for direct CP violation. A brief review of CP violation in hyperon decays is given, the HyperCP spectrometer is described, and the status of the analysis and future prospects are discussed.