Properties of heavy unstable particles

Abstract

A block of emulsion consisting of unbacked emulsion sheets can be used as a very efficient detector for heavy unstable particles and provide favorable conditions for mass and energy determinations. The mass of the τ meson was obtained as m_τ=3m_p+Q, where Q=76.0±0.9 Mev. Fairly accurate mass values are obtained for the positive K meson and four examples of the capture of negative heavy mesons are presented, two of them leading to emission of a p meson. A charged particle of mass higher than that of a proton which decays in flight into a meson is discussed. In most of these cases the nuclear event giving rise to the heavy mesons could be observed. The Q value of the V₁⁰ particle was determined as 37±2 Mev and other examples which may represent the decay of neutral particles are discussed.