The lambda trigger for the E704 Forward Spectrometer

Abstract

The E704 Forward Spectrometer was designed to detect the inclusive production of hyperons (\Lambda\sp0, \Sigma\sp0) by a 200 GeV/c polarized proton beam incident upon an unpolarized liquid hydrogen target. This measurement used a four level trigger to detect lambdas, both from direct production and from \Sigma\sp0 decay. This trigger used four hodoscopes and two levels of programmable logic. The correlations fed into the programmable logic (Memory Lookup Units and Programmable Logic Units) were calculated using a GEANT3 Monte Carlo program. The trigger was tested and then used during the 1990/91 fixed-target run at Fermilab. It was gradually refined during the run. We were eventually able to see lambdas, but the reconstruction rate was low due to tracking limitations, chamber inefficiencies, background processes, etc