Evidence for $e^+e^-\to\gamma\chi_{c1, 2}$ at center-of-mass energies from 4.009 to 4.360 GeV

TL;DR

This study reports evidence for the processes $e^+e^- o\gamma\chi_{c1,2}$ at energies between 4.009 and 4.360 GeV, measuring cross sections and establishing statistical significance for these rare events.

Contribution

First evidence of $e^+e^- o\gamma\chi_{c1,2}$ processes at these energies with measured cross sections and significance levels.

Findings

Evidence for $e^+e^- o\gamma\chi_{c1}$ with 3.0σ significance.

Evidence for $e^+e^- o\gamma\chi_{c2}$ with 3.4σ significance.

Cross sections and upper limits determined at each energy.

Abstract

Using data samples collected at center-of-mass energies of $\sqrt{s}$ = 4.009, 4.230, 4.260, and 4.360 GeV with the BESIII detector operating at the BEPCII collider, we perform a search for the process $e^+e^-\to\gamma\chi_{cJ}$ $(J = 0, 1, 2)$ and find evidence for $e^+e^-\to\gamma\chi_{c1}$ and $e^+e^-\to\gamma\chi_{c2}$ with statistical significances of 3.0$\sigma$ and 3.4$\sigma$, respectively. The Born cross sections $\sigma^{B}(e^+e^-\to\gamma\chi_{cJ})$, as well as their upper limits at the 90% confidence level are determined at each center-of-mass energy.