This title appears in the Scientific Report :
2013
Please use the identifier:
http://hdl.handle.net/2128/5534 in citations.
Please use the identifier: http://dx.doi.org/10.1103/PhysRevD.87.092011 in citations.
Measurement of η′→π+π−e+e− and η′→π+π−μ+μ−
Measurement of η′→π+π−e+e− and η′→π+π−μ+μ−
Based on a sample of 225.3 million J/\psi events accumulated with the BESIII detector at the BEPCII, the decays of \eta' to pi+pi-l+l- are studied via J/\psi to \gamma\eta'. A clear \eta' signal is observed in the pi+pi-e+e- mass spectrum, and the branching fraction is measured to be...
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Please use the identifier: http://dx.doi.org/10.1103/PhysRevD.87.092011 in citations.
Based on a sample of 225.3 million J/\psi events accumulated with the BESIII detector at the BEPCII, the decays of \eta' to pi+pi-l+l- are studied via J/\psi to \gamma\eta'. A clear \eta' signal is observed in the pi+pi-e+e- mass spectrum, and the branching fraction is measured to be \BR(\eta' to pi+pi-e+e-) = (2.11\pm0.12 (stat.)\pm0.15 (syst.))\times10^{-3}, which is in good agreement with theoretical predictions and the previous measurement, but is determined with much higher precision. No \eta' signal is found in the pi+ pi- mu+ mu- mass spectrum, and the upper limit is determined to be \BR(\eta' to pi+ pi- mu+ mu-)<2.9\times10^{-5} at the 90% confidence level. |