Testing the PCAC prediction for the π0 lifetime

We compare the PCAC prediction based on the chiral anomaly for the π⁰ lifetime with a recent experiment. We find that the QED corrections are as large as 3%. After these corrections the experiment and the PCAC prediction disagree by 8.5 ± 2%. We estimate the corrections to the PCAC prediction. We find that reliably calculable corrections are not large enough to account for the discrepancy. However, contributions from the excited π⁰'s may be able to explain the difference.