A new particle

Strong experimental evidence for the existence of a new particle was presented in the form of a photograph of cosmic ray phenomena taken in the Swiss Alps in Europe at a symposium on cosmic rays held at California Institute of Technology, Pasadena, Calif., according to the New York Times (June 21, 1948). The symposium was held in honor of Doctor Robert A. Millikan, dean of American physicists and winner of the Nobel prize for his measurement of the charge of the eleclron. The photograph, shown by Doctor Louis Leprince-Ringuet, French physicist of the University of Paris, indicates the existence of a fundamental particle with a mass greater than 750 and possibly as high as 900. The new particle belongs to the family of cosmic ray products known as mesons or mesotrons. These mesons are believed to be the result of the interaction between the primary cosmic rays originating in interstellar space and the nuclei of atoms in our atmosphere.