Measurement of Double Charmonium Production in $e^+e^-$ Annihilations at $\sqrt{s}=10.6$ GeV

TL;DR

This study measures the production rates of double charmonium states in electron-positron collisions at 10.6 GeV, confirming previous observations and providing new cross-section measurements for specific charmonium pairs.

Contribution

It presents new measurements of double charmonium production cross sections at B-factory energies, confirming earlier signals and refining the quantitative understanding of these processes.

Findings

Signals observed for $ ta_c(1S)$, $ ta_{c0}$, and $ ta_c(2S)$ in recoil mass distribution.

Measured cross sections for $e^+e^- o J/psi + car{c}$ with different charmonium states.

Results agree with and improve upon previous measurements of double charmonium production.

Abstract

We study $e^+e^-\to J/\psi c\bar{c}$ by measuring the invariant mass distribution recoiling against fully reconstructed $J/\psi$ decays, using 124 fb$^{-1}$ of data collected with a center-of-mass energy of 10.6 GeV with the $BaBar$ detector. We observe signals for $\eta_c(1S)$, $\chi_{c0}$, and $\eta_c(2S)$ in the recoil mass distribution, thus confirming previous measurements. We measure $\sigma(e^+e^-\to J/\psi+c\bar{c}) {\cal B} (c\bar{c} \to >2 \mathrm{charged})$ to be $17.6\pm2.8\textrm{(stat)}^{+1.5}_{-2.1}\textrm{(syst)}$ fb, $10.3\pm2.5\textrm{(stat)}^{+1.4}_{-1.8}\textrm{(syst)}$ fb, and $16.4\pm3.7\textrm{(stat)}^{+2.4}_{-3.0}\textrm{(syst)}$ fb with $c\bar{c}=\eta_c(1S)$, $\chi_{c0}$, and $\eta_c(2S)$, respectively.