Narrow e+e- peaks in heavy-ion collisions as possible evidence of a confining phase of QED.

Abstract

We suggest that the correlated narrow-peak structures in ${e}^{+}{e}^{\ensuremath{-}}$ spectra observed in heavy-ion collisions at GSI are due to the decay of a bound ${e}^{+}{e}^{\ensuremath{-}}$ system formed in a new phase of QED. We discuss the mass spectrum for this confined positronium system. Observation of correlated photons of energy \ensuremath{\lesssim}150 keV in the center-of-mass frame at GSI will be further evidence of this new phase, the existence of which has strong support from studies of lattice QED.