TRIGGER FOR THE SEPARATION OF RARE EVENTS USING THE LIKELIHOOD RATIO METHOD

Optimization of a trigger on charm is proposed on the basis of the lik elihood ratio method. This method allows the experimental sampling set to be additionally enriched with charmed particles. A two-level trigg er was analyzed with respect to two independent criteria: increased tr ansverse momentum p(t) of secondary particles and a large impact param eter of these particles relative to the primary interaction point. Dep endence of the charm enrichment coefficient and the charm acceptance o n the trigger parameters was studied for a modified SVD-2 setup with a n active semiconductor target and a high-precision vertex detector. Nu merical estimates were obtained by the Monte-Carlo simulation of pp-in teractions at 70 GeV/c using the PYTHIA and GEANT3 program packages. A scheme of electronics for implementing the proposed method is analyze d.