Search for the $\eta_{c2}(1D)$ in $e^+e^-\to\gamma\eta_{c2}(1D)$ at $\sqrt{s}$ near 10.6 GeV at Belle

TL;DR

This study searches for the $ ext{eta}_{c2}(1D)$ charmonium state in electron-positron collisions near 10.6 GeV using Belle data, but finds no significant signal and sets upper limits on production cross sections.

Contribution

First experimental search for $ ext{eta}_{c2}(1D)$ in $e^+e^-$ collisions at these energies, providing upper limits on its production and decay rates.

Findings

No significant $ ext{eta}_{c2}(1D)$ signal observed.

Upper limit on cross section times branching fraction is 4.9 fb.

Data collected at three different energies near 10.6 GeV.

Abstract

For the first time we search for the $\eta_{c2}(1D)$ in $e^+e^-\to\gamma\eta_{c2}(1D)$ at $\sqrt{s}$ = 10.52, 10.58, and 10.867 GeV with data samples of 89.5 fb$^{-1}$, 711 fb$^{-1}$, and 121.4 fb$^{-1}$, respectively, accumulated with the Belle detector at the KEKB asymmetric energy electron-positron collider. No significant $\eta_{c2}(1D)$ signal is observed in the mass range between 3.8 and 3.88 GeV/$c^2$. The upper limit at 90\% confidence level on the product of the Born cross section for $e^+e^- \to \gamma\eta_{c2}(1D)$ and branching fraction for $\eta_{c2}(1D)\to \gamma h_c(1P)$ is determined to be $\sigma(e^+e^- \to \gamma\eta_{c2}(1D)){\cal B}(\eta_{c2}(1D)\to \gamma h_c(1P))$ $<$ 4.9 fb at $\sqrt{s}$ near 10.6 GeV.