A new type of elementary interaction observed at CERN

Describes recent observations on neutrino interactions at CERN. A beam of protons from a 25 GeV accelerator impinges on a beryllium target and produces a secondary beam of pi mesons. These disintegrate into muons and neutrinos. The protons, mesons and muons are arrested by a heavy steel screen so that only the neutrinos are observed in the Gargamelle bubble chamber. There are strong indications of the existence of neutrino interactions without the production of a muon or electron, which are electrically charged particles. This phenomenon is interpreted as a neutral current which has an intensity predicted by certain theories. It suggests a relationship between two kinds of interactions formerly considered as distinct: weak Fermi interactions and electromagnetic interactions. These two interactions can thus be combined in a unified scheme which overcomes difficulties found in previous theories. (0 refs).