Search for new particles in hadronic events with isolated photons

Abstract

A search for the neutral Higgs boson in the processes e⁺e⁻ → Z → H⁰γ → qqy and e⁺e⁻ → Z → Z∗H⁰ → qqyy has been performed using 2.8 million hadronic Z decays collected with the L3 detector at LEP from 1991 through 1994. No evidence for these processes has been observed. Upper limits at 95% confidence level for the corresponding cross sections have been set and the results have been compared with theoretical predictions beyond the Standard Model.