ABSTRACT
In general we want to find amplitudes which transform under Lorentz transformations linearly: u ′ = D ( L ) u ( L = Lorentz transformation ) https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429492501/e6a0c676-1f8d-4684-97a0-6bf3353f7ce0/content/eq334.tif"/>
