Cloud Chamber Observations of the New Unstable Cosmic Ray Particles

Citation

Seriff, Aaron Jay (1951) Cloud Chamber Observations of the New Unstable Cosmic Ray Particles. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/z5hr-f052. https://resolver.caltech.edu/CaltechTHESIS:07252025-181628906

Abstract

Thirty-five cloud chamber photographs of V-shaped tracks apparently due to the decay of a new unstable neutral particle (V° -particle) and five apparently due to the decay of a new unstable charged particle (V⁺-particle) are discussed. It is shown that only a few of these events could be the result of known processes such as stars in the gas, the scattering of a charged. particle, electron pair production, pi-mu decay or mu-electron decay. The V-particles are shown to originate in the penetrating showers which were selected to trigger the expansion and also in the associated low energy stars. Some evidence for the nature of the decay products is given, and the decay schemes V°→ proton + negative meson and V°→ positive meson + unidentified negative particle are suggested, Calculations of the mass of the V° under the assumption that the decay products an two pi-mesons and again assuming the products are a proton an4 a pi-meson, do not give consistent results in either ease. The discrepant values, 600 to 800 m_e and. 2200 to 2500 m_e, are discussed. The pessib111ty or a three body decay is discussed. A mean life (1.3 x 10^-10sec.) is calculated for the V° assuming the decay into two pi-mesons. It is shown that there are about 40 charged penetrating shower particles per V°-particle.

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