Measurement of the e+ e- → π+π- J/ψ cross section in the vicinity of 3.872 GeV

We report a measurement of the cross section for the process e(+)e(-) -> pi(+)pi(-)J/psi around the X(3872) mass in search for the direct formation of e(+)e(-) -> X(3872) through the two-photon fusion process. No enhancement of the cross section is observed at the X(3872) peak and an upper limit on the product of electronic width and branching fraction of X(3872) -> pi(+)pi(-) J/psi is determined to be Gamma(ee) x B(X(3872) -> pi(+)pi(-) J/psi) <7.5 x 10(-3) eV at 90% confidence level under an assumption of total width of 1.19 +/- 0.21 MeV. This is an improvement of a factor of about 17 compared to the previous limit. Furthermore, using the latest result of B(X(3872) -> pi(+)pi(-) J/psi), an upper limit on the electronic width Fee of X(3872) is obtained to be <0.32 eV at the 90% confidence level.