Current status of the neutrino

Although the neutrino was invented more than fifty years ago, they have learned very little about this elusive creature. The neutrino mass, its behavior under charge conjugation, and the precise nature of its coupling in the weak interaction are matters of speculation. Undaunted, experimentalists have mounted heroic experiments to count neutrinos from the sun, to measure the endpoint of the tritium spectrum, to see the neutrino flash from a supernova, and to determine the rate of the rarest process in Nature, ββ decay. He discusses the theoretical significance of the results