An improved measurement of $\eta^\prime\rightarrow e^{+}e^{-}\omega$

TL;DR

This paper reports an improved measurement of the decay rate of $ ext{eta}^ ext{prime} ightarrow e^+ e^- ext{omega}$ using a large data sample, providing more precise branching fraction and transition form factor data to inform meson structure models.

Contribution

The study presents the first measurement of the transition form factor cutoff parameter for this decay, with significantly improved precision over previous results.

Findings

Branching fraction $ imes 10^{-4}$: (1.79 ± 0.09 ± 0.12)

Transition form factor cutoff parameter $ ext{GeV}^{-1}$: (2.92 ± 0.83 ± 0.15)

Results are consistent with previous measurements, with enhanced accuracy.

Abstract

Using a sample of $(10087 \pm 44) \times 10^{6}$ $J/\psi$ events collected with the BESIII detector, an improved measurement of the decay $\eta^{\prime}\rightarrow e^{+}e^{-}\omega$, with $\omega\rightarrow\pi^{+}\pi^{-}\pi^{0}$ and $\pi^{0}\rightarrow\gamma\gamma$ is performed. The branching fraction is determined to be $\mathcal{B}(\eta^{\prime}\rightarrow e^{+}e^{-}\omega) = (1.79 \pm 0.09 \pm 0.12) \times 10^{-4}$, where the first uncertainty is statistical and the second is systematic. This result is consistent with the previous measurement and is obtained with significantly improved precision. Furthermore, the first measurement of the transition form factor cutoff parameter for this decay is reported, with $\Lambda^{-1} = (2.92 \pm 0.83 \pm 0.15)~\text{GeV}^{-1}$. These measurements provide valuable input for understanding the internal structure of the $\eta^{\prime}$ meson and testing theoretical models.