A New Measurement of the $π^0$ Radiative Decay Width - Nuclear Experiment

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Abstract: High precision measurements of the differential cross sections for $\pi^0$photoproduction at forward angles for two nuclei, $^{12}$C and $^{208}$Pb, havebeen performed for incident photon energies of 4.9 - 5.5 GeV to extract the${\pi^0 \to \gamma\gamma}$ decay width. The experiment was done at JeffersonLab using the Hall B photon tagger and a high-resolution multichannelcalorimeter. The ${\pi^0 \to \gamma\gamma}$ decay width was extracted byfitting the measured cross sections using recently updated theoretical modelsfor the process. The resulting value for the decay width is $\Gamma{\pi^0 \to\gamma\gamma} = 7.82 \pm 0.14 ~{ m stat.} \pm 0.17 ~{ m syst.} ~{ meV}$. With the 2.8% total uncertainty, this result is a factor of 2.5 moreprecise than the current PDG average of this fundamental quantity and it isconsistent with current theoretical predictions.

Autor: I. Larin, D. McNulty, E. Clinton, P. Ambrozewicz, D. Lawrence, I. Nakagawa, Y. Prok, A. Teymurazyan, A. Ahmidouch, A. Asratyan, K

Fuente: https://arxiv.org/