Measurement of the Born cross section for $e^{+}e^{-}\to \eta h_c $ at center-of-mass energies between 4.1 and 4.6\,GeV

TL;DR

This study measures the cross section of the process $e^{+}e^{-} ightarrow ext{eta} ext{h}_c$ across energies from 4.129 to 4.600 GeV, revealing a significant resonance near 4.200 GeV with detailed parameters.

Contribution

First measurement of the $e^{+}e^{-} ightarrow ext{eta} ext{h}_c$ cross section over this energy range, identifying a new resonance structure near 4.200 GeV.

Findings

Resonant structure observed near 4.200 GeV with 7σ significance.

Measured resonance parameters: mass and width with uncertainties.

Cross section exhibits a clear resonance line shape.

Abstract

We measure the Born cross section for the reaction $e^{+}e^{-} \rightarrow \eta h_c$ from $\sqrt{s} = 4.129$ to $4.600$~GeV using data sets collected by the BESIII detector running at the BEPCII collider. A resonant structure in the cross section line shape near 4.200~GeV is observed with a statistical significance of 7$\sigma$. The parameters of this resonance are measured to be \MeasMass\ and \MeasWidth, where the first uncertainties are statistical and the second systematic.