ABSTRACT
We have discussed electrodynamics. The only other process about which quantitative calculations can be made is β decay. It was first observed in some nuclei that N → P + e + ν ¯ https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429492501/e6a0c676-1f8d-4684-97a0-6bf3353f7ce0/content/eq691.tif"/> ( ν ¯ https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429492501/e6a0c676-1f8d-4684-97a0-6bf3353f7ce0/content/eq692.tif"/> is defined to be the antineutrino). You know about the neutrino. Its existence was postulated in order to preserve conservation of energy, momentum, and spin. It can have 0 mass and has spin 1/2.
