Metamorphosis

Letters to the Editor from Oak Ridge and Chalk River appearing in the May 1 issue of the Physical Review give results of recent experimental work on the instability of the neutron. A. H. Snell, F. Pleasanton, and R. V. McCord of the Oak Ridge National Laboratory reported an experiment in which neutrons from the uranium–graphite reactor at Oak Ridge were beamed through an evacuated tank and coincidence events observed with an appropriate counting arrangement. Evidence was obtained for the existence of events involving the appearance of low energy positive particles of roughly protonic mass and of others that might have been beta particles. “The observations would be explained completely and without internal contradiction,” said the authors, “if neutrons in free flight transform spontaneously into protons with the emission of beta particles having a maximum energy of less than about 0.9 Mev.”