Cross section measurement of $e^+e^- \rightarrow \eta'J/\psi$ from $\sqrt{s} = 4.178$ to $4.600$ GeV

TL;DR

This paper measures the cross section of the process $e^+e^- ightarrow ext{eta'} J/ ext{psi}$ across energies from 4.178 to 4.600 GeV, revealing an enhancement around 4.2 GeV and suggesting interference effects between states.

Contribution

First measurement of the cross section for $e^+e^- ightarrow ext{eta'} J/ ext{psi}$ in this energy range with detailed energy dependence analysis.

Findings

Observed cross section enhancement near 4.2 GeV.

Single resonance models cannot fully explain the data.

Interference between $ ext{psi}(4160)$ and $ ext{psi}(4260)$ states improves fit.

Abstract

The cross section of the process $e^+e^- \rightarrow \eta'J/\psi$ is measured at center-of-mass energies from $\sqrt{s} =$ 4.178 to 4.600 GeV using data samples corresponding to a total integrated luminosity of 11 fb$^{-1}$ collected with the BESIII detector operating at the BEPCII storage ring. The dependence of the cross section on $\sqrt{s}$ shows an enhancement around $4.2$ GeV. While the shape of the cross section cannot be fully explained with a single $\psi(4160)$ or $\psi(4260)$ state, a coherent sum of the two states does provide a reasonable description of the data.