A. Zee, Quantum Field Theory in a Nutshell · Problem VIII.4.3
Field Theory Redux
Physics — QFT
Problem
From the fact that we do not know how to write consistent quantum field theories with fields having spin greater than 2 show that the N in the previous exercise cannot exceed 8. Theories with N=8 supersymmetry are said to be maximally supersymmetric. Show that if we do not want to include gravity, N cannot be greater than 4. Supersymmetric N=4 Yang-Mills theory has many remarkable properties.