Measurement of Γ_{ee}(J/ψ)*Br(J/ψ->e^+e^-) and Γ_{ee}(J/ψ)*Br(J/ψ->μ^+μ^-)

Abstract

The products of the electron width of the J/ψmeson and the branching fraction of its decays to the lepton pairs were measured using data from the KEDR experiment at the VEPP-4M electron-positron collider. The results are Γ_{ee}(J/ψ)*Br(J/ψ->e^+e^-)=(0.3323\pm0.0064\pm0.0048) keV, Γ_{ee}(J/ψ)*Br(J/ψ->μ^+μ^-)=(0.3318\pm0.0052\pm0.0063) keV. Their combinations Γ_{ee}\times(Γ_{ee}+Γ_{μμ})/Γ=(0.6641\pm0.0082\pm0.0100) keV, Γ_{ee}/Γ_{μμ}=1.002\pm0.021\pm0.013 can be used to improve theaccuracy of the leptonic and full widths and test leptonic universality. Assuming eμuniversality and using the world average value of the lepton branching fraction, we also determine the leptonic Γ_{ll}=5.59\pm0.12 keV and total Γ=94.1\pm2.7 keV widths of the J/ψmeson.

7 pages, 6 figures

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Cited by in corpus (8)

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• New Parity-Violating Muonic Forces
• Measurement of the phase between strong and electromagnetic amplitudes of $J/\psi$ decays
• Measurement of the leptonic decay width of $J/\psi$ using initial state radiation
• Measurement of the ratio of the leptonic widths ${\Gamma }_{ee}/{\Gamma }_{\mu \mu }$ for the $J/\psi$ meson
• Measurement of ${\Gamma }_{ee}\times {\mathcal{B}}_{\mu \mu }$ for $\psi (2S)$ meson
• A discussion on vacuum polarization correction to the cross-section of $e^{+}{e}^{-}\to {\gamma }^{\ast }/\psi \to {\mu }^{+}{\mu }^{-}$
• Analytical Forms for Cross Sections of Di-lepton Production from $e^{+}{e}^{-}$ Collisions around the $J/\psi$ Resonance