$\pi^{0}$ meson radiative width results on $^{12}$C from the PrimEx collaboration at Jefferson Lab

The $\pi^{0}$ lifetime is arguably the most precise theoretical calculation possible in low energy QCD, but current world's data is not commensurate with current theory. The next-to-leading order Chiral Perterbation Theory calculation [hep-ph/0206007] calls for a $\pi^{0}$ radiative width of 8.1 eV $\pm$ 1\%. The PDG average stands at 7.84 eV $\pm$ 7\%. The Primakoff Experiment (PrimEx) collaboration has utilized the Primakoff effect, photo-meson production in the Coulomb field of nuclei, to measure the $pi^{0}$ radiative width. The final sensitivity of this $\pi^{0}$ lifetime measurement is expected to approach 1.5\%. The PrimEx collaboration recorded data in the Fall of 2004 in Hall B of the Thomas Jefferson National National Accelerator Facility. Preliminary results for this run will be presented. This is expected to be a stringent test of the U(1) axial anomaly and thus fill an important gap in our knowledge of low energy QCD.