Complete Spin Tests for Fermions

Abstract

Complete spin tests for fermions of arbitrary spin, produced from a spin-zero boson on an unpolarized spin-\textonehalf{} fermion and decaying into a spin-zero boson and a spin-\textonehalf{} fermion, are derived. The tests constitute a set of necessary and sufficient conditions for a particular spin assignment, in the absence of more detailed dynamical information. Essential use is made of the $R$ invariance of the parity conserving production process. More general tests, applicable to arbitrary production processes, are also discussed.