Use of discriminant analysis in search of a neutral Higgs boson

When searching for the Higgs boson produced in e+e− collisions at energies close to the Z0 mass, a method to reject a very large background is needed. A method to pick up the signal of a Higgs boson produced in association with a pair of neutrinos has been investigated. After a preselection, which eliminates the majority of the background events, a discriminant analysis was used to achieve a background rejection factor of 168 while keeping an efficiency for Higgs boson events of 68% for a Higgs boson mass of 55 GeV/c2. For the combined preselection and discriminant analysis, the rejection factor is 50 000 and the efficiency is 48%.