Study of $e^+e^-\to \Upsilon(\rm1S,2S)\eta$ and $e^+e^-\to \Upsilon(\rm 1S)\eta^{\prime}$ at $\sqrt{s}=10.866$ GeV with the Belle detector

TL;DR

This paper reports the first observation of specific bottomonium production processes involving eta mesons at 10.866 GeV, measuring their cross sections and setting limits on related processes, advancing understanding of quarkonium production mechanisms.

Contribution

First observation of $e^+e^- o ext{Upsilon}(1S,2S) ext{eta}$ processes at this energy with measured cross sections and upper limits on related channels.

Findings

Observed $e^+e^- o ext{Upsilon}(1S,2S) ext{eta}$ with high significance.

Measured cross sections for these processes.

Set upper limit on $e^+e^- o ext{Upsilon}(1S) ext{eta'}$ cross section.

Abstract

We report the first observation of the processes $e^+e^-\to\Upsilon(\rm 1S,2S)\eta$ at $\sqrt{s}=10.866$~GeV with a $10.2\sigma$ and $16.5\sigma$ significance respectively. The measured Born cross sections are $\sigma(e^+e^- \to \Upsilon(2S)\eta)=2.07 \pm 0.21 \pm 0.19$~pb, and $\sigma(e^+e^- \to \Upsilon(\rm 1S)\eta)=0.42 \pm 0.08 \pm 0.04$~pb. We also set the upper limit on the cross section of the process $e^+e^- \to \Upsilon(\rm 1S)\eta^{\prime}$ to be $\sigma(e^+e^- \to \Upsilon(\rm 1S)\eta^{\prime})<0.035$~pb at $90\%$ CL. The results are obtained with the data sample collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider in the energy range from $10.63$~GeV to $11.02$~GeV.