Hyperon Beam Experiment

The experiment WA89 uses the upgraded Omega facility together with a hyperon beam installed at the end of the H1 beamline. The beam can deliver 2~10$ ^{5} \% Sigma ^- $ per machine burst at 330 GeV/c with a background of 5 10$ ^{5} \% \pi ^- $. \\ \\ The goals of the experiment are: observation of charmed particles, mainly the charmed-strange baryons and measurements of their production in the kinematical range x$ _{F} $~$>$~0.2, and their decay properties, a search for exotic states such as U(3100) observed in the previous CERN hyperon beam experiment WA62, measurements of hyperon polarization and production properties. \\ \\ A vertex detector consisting of 24 silicon microstrip planes with 25~$\mu$m pitch and 6~planes with 50~$\mu$m pitch provides track measurements of sufficient accuracy to identify the decays of short living charmed particles and measure their lifetimes. A RICH detector provides good $\pi$/K separation for momenta up to 100~GeV/c and $\pi$/p separation up to 150~GeV/c. Photons are detected by a lead glass calorimeter and neutrons by a hadron calorimeter of the ``spaghetti'' type. \\ \\ The experiment had 3 runs of data taking in 1991, 1993 and 1994.