Measurement of Γee(J/ψ) with KEDR detector

Abstract

The product of the electronic width of the J/ψ meson and the branching fractions of its decay to hadrons and electrons has been measured using the KEDR detector at the VEPP-4M e+e− collider. The obtained values areΓee(J/ψ)=5.550±0.056±0.089keV,Γee(J/ψ)·ℬhadrons(J/ψ)=4.884±0.048±0.078keV,Γee(J/ψ)·ℬee(J/ψ)=0.3331±0.0066±0.0040keV. The uncertainties shown are statistical and systematic, respectively. Using the result presented and the world-average value of the electronic branching fraction, one obtains the total width of the J/ψ meson:Γ=92.94±1.83keV. These results are consistent with the previous experiments.