Comment on "A Search for Narrow Sum Energy Lines in Electron-Positron Pair Emission from Heavy Ion collisions near the Coulomb Barrier"

Abstract

The report of Ahmad et al., states that ``No evidence is found for sharp peaks in the present data.'' But this statement is factually inaccurate. Figure 1 exhibits the APEX' published U + Th ``wedge cut'' data, and background, which show a distinct (3.2 sigma) maximum of 83 excess pair counts in the 20 keV bin near 790 keV. A one-gaussian best fit to this excess reduces chi-squared (for the 21 bins from 500 to 920 keV) by 12.6 from 28.3 to 16.7, and the reduced chi-squared value from 1.41 to 0.98. Furthermore, at the 99% Confidence Level, the data impose lower and upper bounds of (24, 146) respectively upon the mean excess pair count in this bin. This data therefore provides positive, statistically significant evidence for sharp pairs near 790 keV. Whether this evidence is compelling is a separate question not addressed here.