A New Measurement of the Pi0 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 $${\pi^0 \to \gamma\gamma}$$ decay width. The experiment was done at Jefferson Lab using the Hall~B photon tagger and a high-resolution multichannel calorimeter. The $${\pi^0 \to \gamma\gamma}$$ 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 $$\Gamma{(\pi^0 \to \gamma\gamma)} = 7.82 \pm 0.14 ~({\rm stat.}) \pm 0.17 ~({\rm syst.}) ~{\rm eV}$$. 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.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- AC05-06OR23177
- OSTI ID:
- 1015428
- Report Number(s):
- JLAB-PHY-10-1229; DOE/OR/23177-1332; arXiv:1009.1681; PRLTAO; TRN: US1102841
- Journal Information:
- Phys.Rev.Lett., Vol. 106, Issue 16; ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
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