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Register a new userNeutral Pion Lifetime Measurements and the QCD Chiral Anomaly
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A fundamental property of QCD is the presence of the chiral anomaly, which is the primary component of the $pi^0rightarrowgammagamma$ decay amplitude. Based on this anomaly and its small ($simeq$ 4.5%) chiral correction, a firm prediction of the $pi^0$ lifetime can be used as a test of QCD at confinement scale energies. The interesting experimental and theoretical histories of the $pi^0$ meson are reviewed, from discovery to the present era. Experimental results are in agreement with the theoretical prediction, within the current ($simeq$ 3%) experimental error; however, they are not yet sufficiently precise to test the chiral corrected result, which is a firm QCD prediction and is known to $simeq$ 1% uncertainty. At this level there exist experimental inconsistencies, which require attention. Possible future work to improve the present precision is suggested.
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