CP violation in strange baryon decays: A report from Fermilab experiment 871

Fermilab experiment 871, HyperCP, is a search for direct CP violation in Ⅺ and Λ hyperon decays. A non-zero value in the asymmetry parameter A, defined in terms of the decay parameter products αⅪαΛ and αⅪ̄αΛ̄, would be unambiguous evidence for direct CP violation. The first data-taking run finished at the end of 1997 and accumulated over one billion Ⅺ− and Ⅺ̄+ decays. A sensitivity in A of ≈10−4 is expected. A review of CP violation in hyperon decays is given, the HyperCP detector is described, and the status of the data analysis is discussed.