Measurement of $J/\psi$ production in continuum $e^+e^-$ annihilations near $\sqrt s = 10.6$ GeV

TL;DR

This study measures the production cross section of $J/$ mesons in electron-positron collisions near 10.6 GeV, distinguishing continuum production from B decay contributions, and sets limits on direct $(4S)$ decays.

Contribution

First measurement of $J/$ production cross section in continuum $e^+e^-$ annihilations near 10.6 GeV with separation from B decay contributions.

Findings

Measured $e^+e^- o J/ X$ cross section as 2.52 pb

Set upper limit on $(4S) o J/ X$ branching fraction at $4.7 imes 10^{-4}$

Identified $J/$ production above 2 GeV/c momentum

Abstract

The production of $J/\psi$ mesons in continuum $e^+e^-$ annihilations has been studied with the BABAR detector at energies near the $\Upsilon(4S)$ resonance, approximately 10.6 GeV. The mesons are distinguished from $J/\psi$ production in B decays through their center-of-mass momentum and energy. We measure the cross section $e^+e^-\to J/\psi X$ to be $2.52\pm 0.21\pm 0.21$ pb; for momentum above 2 GeV/c, it is $1.87\pm 0.10\pm 0.15$ pb. We set a 90% confidence level upper limit on the branching fraction for direct $\Upsilon(4S)$\to J/\psi X$ decays at $4.7\times 10^{-4}$.