Publikace na Matematicko-fyzikální fakulta |
2023
Abstrakt
We measure the cross section of e+e− → ηcJ/ψ at the Υ(nS)(n = 1–5) onresonance and 10.52 GeV off-resonance energy points using the full data sample collected by the Belle detector with an integrated luminosity of 955 fb−1. We also search for double charmonium production in e+e− → ηcJ/ψ via initial state radiation near the ηcJ/ψ threshold.
No evident signal of the double charmonium state is found, but evidence for the e+e− → ηcJ/ψ process is found with a statistical significance greater than 3.3σ near the ηcJ/ψ threshold. The average cross section near the threshold is measured and upper limits of cross sections are set for other regions.