Let's begin with a general amplitude for the two-body decay of a state with angular momentum quantum numbers ''J'',''m''. Specifically, we want to know the amplitude of this state having daughter 1 with trajectory <math>\Omega=(\phi,\theta)</math>. | Let's begin with a general amplitude for the two-body decay of a state with angular momentum quantum numbers ''J'',''m''. Specifically, we want to know the amplitude of this state having daughter 1 with trajectory <math>\Omega=(\phi,\theta)</math>. |