Search for elusive neutral particles in nuclear decay

Abstract

An experimental search has been performed for short-lived 0+ and 1- particles in the 0+ to 0+ transition at 6.05 MeV in 16O. No decays into electron-positron pairs which could be attributed to such particles have been observed above the continuum of internal pair creation. The authors deduce upper limits for the branching ratio and show the still allowed parameter region for the existence of short-lived elusive particles.