Production of new particles in heavy-ion collisions

Abstract

Experimentally observed sharp lines in the positron-emission spectra resulting from low-energy heavy-ion collisions are interpreted in terms of the production and subsequent decay of a neutral, pseudoscalar particle. This particle has a mass of about 1.6 MeV and a lifetime of about 1.3\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}13}$ sec.