New atomic mechanism for positron production in heavy-ion collisions

This letter gives a newly considered mechanism for positron production which consists of filling of long-lived, supercritical, multiple-vacancy states via higher-order perturbations, with interference terms of the same order of magnitude as in the case of the previously considered single vacancies. This mechanism could be relevant to the structure in positron energy spectra observed at Gesell- schaft fuer Schwerionenforschung in heavy-ion collisions. A possible directional anisotropy of positron emission is discussed