Measurement of the branching fraction for $\psi(3770) \to \gamma\chi_{c0}$

TL;DR

This paper reports the most precise measurement to date of the branching fraction and partial decay width for the radiative decay of $ ext{psi}(3770)$ to $ ext{chi}_c0$ using data from BESIII at BEPCII.

Contribution

It provides the first highly precise measurement of the $ ext{psi}(3770) o ext{gamma} ext{chi}_c0$ decay parameters, improving upon previous results.

Findings

Branching fraction: (6.88 ± 0.28 ± 0.67) × 10^{-3}

Partial decay width: (187 ± 8 ± 19) keV

Most precise measurements to date

Abstract

By analyzing a data set of 2.92 fb$^{-1}$ of $e^+e^-$ collision data taken at $\sqrt s= 3.773~\rm GeV$ and 106.41$\times 10^{6}$ $\psi(3686)$ decays taken at $\sqrt s= 3.686~\rm GeV$ with the BESIII detector at the BEPCII collider, we measure the branching fraction and the partial decay width for $\psi(3770)\to\gamma\chi_{c0}$ to be ${\mathcal B}(\psi(3770)\to\gamma\chi_{c0})=(6.88\pm0.28\pm0.67)\times 10^{-3}$ and $\Gamma[\psi(3770)\to\gamma\chi_{c0}]=(187\pm8\pm19)~\rm keV$, respectively. These are the most precise measurements to date.