Rarita–Schwinger equation

The Rarita-Schwinger equation is a fundamental equation in theoretical physics that describes particles with spin 3/2, which are often referred to as "Rarita-Schwinger fields." It generalizes the Dirac equation, which describes spin-1/2 particles like electrons, to account for higher-spin fermionic fields. The equation is named after physicists Walter Rarita and Julian Schwinger, who introduced it in 1941.