Cloud-Chamber Study of ChargedVParticles

Abstract

An analysis of 103 charged $V$-particle decays is presented. These events have been observed with a double cloud chamber operated at 1750-m altitude. The events in the upper chamber appear to have markedly different properties from those in the lower. The particles in the upper chamber have measured properties which are in every respect consistent with those of the $\kappa$ meson. Their lifetime is in the range 5×${10}^{-10\mathrm{}}$ to 2×${10}^{-8\mathrm{}}$ sec; their mass is $\sim 1000 m_e$; their transverse momentum distribution is consistent with a three-body decay scheme; the momentum in the center-of-mass system of their charged decay products is also consistent with three-body decay; and their frequency of production is greater than 0.4 percent of the total number of shower particles observed. On the other hand, the particles observed in the lower chamber have a lifetime in the range ${10}^{-11\mathrm{}}$ to 3×${10}^{-10\mathrm{}}$ sec; their transverse momentum distribution is consistent with a two-body decay scheme; their frequency of production is greater than 0.8 percent of the total number of shower particles; they are observed with approximately one-third of the frequency of ${\Lambda }^0$ particles; and they apparently can be produced in meson-nucleon collisions. The majority of the particles in the lower chamber are tentatively identified as charged hyperons with the aid of two cases which appear to have proton secondaries. The proposed decay scheme is ${V_1}^{+}\to p+{\pi }^0+Q$; and in order to fit all of the data, the alternate mode of decay, ${V_1}^{+}\to {\pi }^{+}+n+Q$ must be introduced. The $Q$ value is estimated to be ≲125 Mev.