Answers are grounded in this paper and cite their sources.
(1955). Ionization at the origin of electron Pairs, and the lifetime of the neutral pion. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science: Vol. 46, No. 381, pp. 1146-1148.
No takes yet. Share an insight, caveat, or question.
D.H. Perkins (1955) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: