Corrections and Clarifications


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Science  04 Nov 1949:
Vol. 110, Issue 2862, pp. 482
DOI: 10.1126/science.110.2862.482


In my report on the Echo Lakes Symposium on Cosmic Rays (Science, September 2, 1949) the π- and µ-symbols were interchanged, in the line before last of the second column, p. 242, and in the first line of the third column in the same page. The portion of the text containing these two lines should read: ". . . the latest values for the masses of the µ- and the π-meson (215 and 285 electron masses respectively) and for the mean life of the π-meson (0.63x10–8 see)." In a recent letter to the writer, Dr. Barkas states that this value for the mean life of the π-meson has been superseded by more accurate measurements. These measurements, made on positive π-mesons, give a mean life of 1.97x10–8 sec. Dr. Barkas also indicates that new mass measurements give 276 electron masses for positive or negative π-mesons and 210 electron masses for positive µ-mesons.