Angular Correlation Effects inV-Particle Decay

In decay processes of the types: hyperon→nucleon+pion; or $K$-meson→pion+pion, the most general distribution function in $\eta$—the angle between the decay plane normal and a reference direction N normal to the line of flight of the unstable particle—has the form of a finite Fourier series. The degree of the highest harmonic is simply related to the spin of the unstable particle. The coefficients in the series depend on the state of polarization of the spin with respect to the reference direction N. It is possible however to set upper limits on the coefficients; this may prove useful in any attempt to analyze angular correlation data, particularly in the case of hyperon decay. The upper limits for various low spin values are computed, and other consequences of the angular momentum and parity conservation laws are discussed.