A Study of NeutralVParticles

The $V$ particles produced in penetrating showers have been studied in a cloud chamber containing lead plates. The results can be interpreted in terms of two types of neutral unstable particles, ${V_1}^0\to p+\pi$ and ${V_2}^0\pi +\pi$, although other possibilities are not excluded by our data. Analysis of the dynamics of three-particle decay indicates that such a process must still be considered as possible. The lifetimes of the particles have been calculated, taking into account the bias introduced by the finite size of the cloud chamber. If we use average values for the masses of the unstable particles, the lifetime for the ${V_1}^0$ is (10±7)×${10}^{-10\mathrm{}}$ sec and for the ${V_2}^0$ is (4±3)×${10}^{-10\mathrm{}}$ sec.