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 Ξ− (“cascade”) decays in the decay sequence: Ξ− → π− + Λ0, Λ0 → π− + p, with those for the antiparticle Ξ̄+. 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 Ξ− and Ξ̄+ decays, and 19 million Ω− and Ω̄+ decays. This is the largest sample of fully reconstructed particle decays ever collected. © 2002 American Institute of PhysicsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87464/2/298_1.pd

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

Fermilab experiment 871, HyperCP, is a search for direct CP violation in Ξ and Λ hyperon decays. A non-zero value in the asymmetry parameter A, defined in terms of the decay parameter products αΞαΛαΞαΛ and ,αΞ̄αΛ̄, would be unambiguous evidence for direct CP violation. The first data-taking run finished at the end of 1997 and accumulated over one billion Ξ−Ξ− and +Ξ̄+ decays. A sensitivity in A of ≈ 10−4≈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. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87472/2/107_1.pd

Measurement of αΩ in Ω− → ΛΚ− Decays

The HyperCP experiment (E871) at Fermilab has collected the largest sample of hyperon decays in the world. With a data set of over a million Ω− → ΛΚ− decays we have measured the product of αΩαΛ from which we have extracted αΩ. This preliminary result indicates that αΩ is small, but non‐zero. Prospects for a test of CP symmetry by comparing the α parameters in Ω− and Ω̄+ decays will be discussed. © 2003 American Institute of PhysicsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87682/2/251_1.pd