Measurement of $\hat{I}{“}_{ee}(J/\ddot{I}ˆ)$ with KEDR detector

Abstract

The product of the electronic width of the $J/\ddot{I}ˆ$ 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 are: $\hat{I}{“}_{ee}(J/\ddot{I}ˆ)=5.550\pm 0.056\pm 0.089\text{keV},$ $\hat{I}{“}_{ee}(J/\ddot{I}ˆ)\cdot {\mathcal{B}}_{\text{hadrons}}(J/\ddot{I}ˆ)=4.884\pm 0.048\pm 0.078\text{keV},$ $\hat{I}{“}_{ee}(J/\ddot{I}ˆ)\cdot {\mathcal{B}}_{ee}(J/\ddot{I}ˆ)=0.3331\pm 0.0066\pm 0.0040\text{keV}.$ 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 $J/\ddot{I}ˆ$ meson: $\hat{I}“=92.94\pm 1.83\text{keV}.$ These results are consistent with the previous experiments.

19 pages, 13 figures