Neutral Pion Decay

The study of π 0 decay has played an important role in the development of particle physics: The π 0 →γγ decay provides key insights into the anomaly sector of quantum chromodynamics. In this review, the historical progression of π 0 discovery, lifetime measurements, and theory are presented. A new measurement of the π 0 radiative width via the Primakoff effect has been made at JLab. The result, Γ(π 0 →γγ)=7.82±0.14(stat.)±0.17(syst.) eV, is a...