Recent heavy ion experiments at GSI have releaved anomalous electron-positron coincidences. The anomalous events seem to come from something that decays into a two-body final state. It has been proposed that a 1.8 MeV axion could explain the data. However, both conventional axion theory and more recent variants are inconsistent with existing measurements of electron-positron angular correlations in nuclei. Beam dump experiments also exclude the axion theories. We discuss the old data and new measurements in terms of the axion theory and a more general particle explanation for the GSI result.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics