Erratum: Study of the Dalitz decay J/ψ→e+e−η [Phys. Rev. D 99 , 012006 (2019)

M Ablikim

doi:10.1103/physrevd.104.099901

Abstract

We report corrected results on a study of the electromagnetic Dalitz decay $J/\psi \to e^+e^- \eta$ and search for di-electron decays of a light dark gauge boson ($\gamma'$) in $J/\psi \to \gamma' \eta$ with the two $\eta$ decay modes $\eta \rightarrow \gamma \gamma$ and $\eta \rightarrow \pi^+\pi^-\pi^0$, using $(1310.6\pm 7.0)\times10^6$ $J/\psi$ events collected with the BESIII detector. In particular we update the measurement of the pole mass of the transition form factor (TFF) of $J/\psi \to e^+e^- \eta$ to be $\Lambda = 2.56 \pm 0.04({\rm stat}) \pm 0.03({\rm syst})$ GeV/$c^2$. The branching fraction of $J/\psi \to e^+e^-\eta$ and the kinetic-mixing strength between the Standard Model photon and $\gamma'$ are also updated after taking the corrected $\Lambda$ value into account. The measured branching fraction of $J/\psi \to e^+e^- \eta$ is updated to be $(1.42 \pm 0.04({\rm stat}) \pm 0.07 ({\rm syst}))\times 10^{-5}$, where the first and second uncertainties are statistical and systematic, respectively.

Highlights

We reported the study of the electromagnetic (EM) Dalitz decay J=ψ → eþe−η and search for di-electron decays of a light dark gauge boson (γ0) in J=ψ → γ0η with the two η decay modes η → γγ and η → πþπ−π0 using ð1310.6 Æ 7.0Þ × 106 J=ψ events collected with the BESIII detector
The dielectron invariant mass-dependent transition form factor (TFF) in this decay describes the deviation from the standard pointlike prediction of quantum electrodynamics (QED) and serves as a sensitive probe of the inner structure of the mesons involved in the process [1]
We update the branching fraction of J=ψ → eþe−η in both decay modes of η → γγ and η → πþπ−π0 after evaluating the efficiency with the simulated signal MC sample generated with the measured Λ 1⁄4 2.56 GeV=c2

Summary

Introduction

We report here corrected results on a study of the electromagnetic Dalitz decay J=ψ → eþe−η and search for dielectron decays of a light dark gauge boson (γ0) in J=ψ → γ0η with the two η decay modes η → γγ and η → πþπ−π0, using ð1310.6 Æ 7.0Þ × 106 J=ψ events collected with the BESIII detector. The dielectron invariant mass-dependent transition form factor (TFF) in this decay describes the deviation from the standard pointlike prediction of quantum electrodynamics (QED) and serves as a sensitive probe of the inner structure of the mesons involved in the process [1].

Results

Conclusion