COMMENT ON MAGNETIC e~eRESONANCES IN A CENTRAL FIELD

Within a simple semiclassical model it is shown that the presence of an external Coulomb field induces only slight changes in the energy of a resonant electron—positronstate unless for extremely small distances, while the width increases strongly with the field strength. A great puzzle in present day physics is the inter- energy in both positron and electron spectra recorded pretation of narrow lines in the spectrum of posi- in coincidence [121 stimulated an alternative expla-trons emitted invery heavy ion collisions. Originally, nation in terms of a decaying magnetic resonance of these experimental investigations had been moti- the e~e binary system [131. It was suggested [141 vated by theory [1,21 which predicts a spontaneous to describe the e~e — pair by the relativistic spinor production of positrons as soon as the charge Z of equation [15] the combined nuclear system exceeds a criticalvalue (Zcr 173). The knowledge of both Z and the time {c~,[p ~ +(elc)A, ] +c~2 [P2 — (e/c)A2 I where the colliding nuclei are sufficiently close together, allows for an estimate of the structure of +/31 m