Study of double charmonium production in e^+ e^- annihilation at \sqrt{s} ~ 10.6 GeV

TL;DR

This paper analyzes double charmonium production in electron-positron annihilation at around 10.6 GeV, confirming several processes with a larger dataset and discovering new production channels, while setting limits on others.

Contribution

It provides new measurements of double charmonium production processes with a larger dataset and reports first observations of certain production channels.

Findings

Confirmed e^+ e^- -> J/psi eta_c, J/psi chi_c0, J/psi eta_c(2S) processes.

No evidence found for e^+ e^- -> J/psi J/psi.

First observation of e^+ e^- -> psi(2S) (cc)_res processes.

Abstract

We present a new analysis of double charmonium production in e^+ e^- annihilation. The observation of the processes e^+ e^- -> J/psi eta_c, J/psi chi_c0, and J/psi eta_c(2S) is confirmed using a dataset more than three times larger than that of Belle's previous report, and no evidence for the process e^+ e^- -> J/psi J/psi is found. We perform an angular analysis for J/psi eta_c production and set an upper limit on the production of J/psi J/psi. Processes of the type e^+ e^- -> psi(2S) (cc)_res have been observed for the first time; their rates are found to be comparable to those of e^+ e^- -> J/psi (cc)_res processes.