Determining the upper limit of Gamma_{ee} for the Y(4260)

By fitting the R values between 3.7 and 5.0 GeV measured by the BES collaboration, the upper limit of the electron width of the newly discovered resonance Y(4260) is determined to be 580 eV at 90% C.L. Together with the BABAR measurement on the product of Gamma_{ee} and BR(Y(4260) --> pi+pi- J/psi), this implies a large decay width of Y(4260) --> pi+pi- J/psi final states.