The Neutrino Is Born as an Idea

New ideas that lead to progress in science come in many ways. Often theories follow experiments but sometimes, the reverse can be true. Classic examples of theories following experiments in physics are, Faraday’s law and Oersted’s discovery of connection between electricity and magnetism that established the correct laws governing electricity. Bohr’s atomic theory that led to the whole framework of quantum mechanics, and in more recent times, the idea of no mirror asymmetry in nature enunciated by T. D. Lee and C. N. Yang, are also of this kind. In the field of biology, the famous double helix structure of DNA proposed by James Watson and Francis Crick which opened up new frontiers in biology also belongs to the first category. There are also equally illustrious example of experiments following theory. For example, Hertz’s discovery of electromagnetic waves, which is behind radio and TV signal transmission, came following the theoretical suggestion of electromagnetic waves by Maxwell, and discovery of pi meson followed the suggestion of Yukawa. The pi meson opened up the field of nuclear and particle physics. One could include the discovery of gravity waves as experimental discovery following theory as well. The same pattern of close symbiosis between theory and experiment, with one influencing the other, has continued into the current century. Idea of the neutrino belongs to the first category as we explain below.