Observation of $e^{+}e^{-}\rightarrow\eta\psi(2S)$ at center-of-mass energies from 4.236 to 4.600 GeV

TL;DR

This paper reports the first observation of the process e+e- to eta psi(2S) in the energy range 4.236 to 4.600 GeV, using BESIII data, with measurements of cross sections and energy dependence.

Contribution

First observation of e+e- to eta psi(2S) process at these energies with detailed cross section measurements.

Findings

Observation with 5 sigma significance.

Measured cross sections across energy range.

Energy dependence of the process established.

Abstract

Using a total of $5.25~{\rm fb}^{-1}$ of $e^{+}e^{-}$ collision data with center-of-mass energies from 4.236 to 4.600 GeV, we report the first observation of the process $e^{+}e^{-}\to \eta\psi(2S)$ with a statistical significance of $5\sigma$. The data sets were collected by the BESIII detector operating at the BEPCII storage ring. We measure the yield of events integrated over center-of-mass energies and also present the energy dependence of the measured cross section.