APEX: Positive evidence for sharp 800 keV pairs from heavy ion collisions near the Coulomb barrier

Abstract

The best fit to the published APEX U+Th data describes a sharp line of 123 pairs of width 23 keV at 793$\pm$7 keV; also, the data impose a positive 99.0%CL lower bound of 23 sharp pairs. It is therefore untenable to argue from the APEX data against the existence of sharp pairs. Data-only ratios APEX/EPOS pair counts show empirically that the two experiments' pair data are mutually consistent and of comparable statistical potency: conflicts, if any, can be resolved only by other independent evidence. A perspective is offered on the current status of the Sharp Lepton Problem, and alternative non-heavy-ion experimental approaches to it are recommended.