New Experimental Evidence for the Existence of a Neutrino

Abstract

A new method is used for determining the energy of recoil of the nucleus in the individual beta-disintegration process. A gaseous compound of radiochlorine is placed in a cloud chamber. The clearing field is removed long enough before the expansion to allow the ions to spread out so that the resulting droplets can be seen individually. A cluster of droplets appears at the beginning of the track, and this is believed to be produced by the recoil nucleus. From the number of droplets an estimate is made of the kinetic energy of the nucleus, and this is compared with that calculated from the observed curvature of the beta-ray track. It is found that the laws of momentum as well as those of energy indicate that a third particle participates in the disintegration.