A fast processor for di-lepton triggers

As a new application of the Fermilab ECL-CAMAC logic modules a fast trigger processor was developed for Fermilab experiment E-537, aiming to measure the higher mass di-muon production by antiprotons. The processor matches the hit information received from drift chambers and scintillation counters, to find candidate muon tracks and determine their directions and momenta. The tracks are then paired to compute an invariant mass: when the computed mass falls within the desired range, the event is accepted. The process is accomplished in times of 5 to 10 microseconds, while achieving a trigger rate reduction of up to a factor of ten. (5 refs).