A New Measurement of the $pi^0$ Radiative Decay Width

High precision measurements of the differential cross sections for $pi^0$ photoproduction at forward angles for two nuclei, $^{12}$C and $^{208}$Pb, have been performed for incident photon energies of 4.9 - 5.5 GeV to extract the ${pi^0 to gammagamma}$ decay width. The experiment was done at Jefferson Lab using the Hall B photon tagger and a high-resolution multichannel calorimeter. The ${pi^0 to gammagamma}$ decay width was extracted by fitting the measured cross sections using recently updated theoretical models for the process. The resulting value for the decay width is $Gamma{(pi^0 to gammagamma)} = 7.82 pm 0.14 ~({rm stat.}) pm 0.17 ~({rm syst.}) ~{rm eV}$. With the 2.8% total uncertainty, this result is a factor of 2.5 more precise than the current PDG average of this fundamental quantity and it is consistent with current theoretical predictions.