S -particles and charged V -particles

Abstract A detailed discussion is given of the known properties of the unstable S-particles and charged V -particles, other than their lifetimes. S-particles are singly charged and decay at rest in thin lead plates inside a cloud chamber into one charged secondary particle and one or more neutral particles. Charged V -particles are also singly charged and decay in flight in the cloud-chamber gas into a charged secondary particle and one or more neutral particles. Some of the S -particles are probably identical with the X-particle, and the charged V -particles probably consist of a mixture of K- and χ-particles.