Measurement of the Matrix Element for the Decay $\eta^{\prime} \to \eta \pi^+\pi^-$

TL;DR

This study analyzes the decay dynamics of $ o o o$ using a large dataset, determining Dalitz plot parameters and the branching fraction of $ o o$, providing detailed insights into the decay process.

Contribution

It presents the largest dataset to date for $ o o o$ decay, accurately measuring Dalitz plot parameters and the branching fraction with improved precision.

Findings

Dalitz plot parameters are precisely determined.

Branching fraction of $ o o$ measured as $(4.84 o 0.03 o 0.24) imes 10^{-3}$.

Largest sample of $ o$ decays enables detailed decay analysis.

Abstract

The Dalitz plot of $\eta^{\prime} \to \eta \pi^+ \pi^-$ decay is studied using $(225.2\pm2.8)\times 10^6$ $\jpsi$ events collected with the BESIII detector at the BEPCII $e^+e^-$ collider. With the largest sample of $\eta^{\prime}$ decays to date, the parameters of the Dalitz plot are determined in a generalized and a linear representation. Also the branching fraction of $\jpsi \to \gamma \eta^{\prime}$ is determined to be $(4.84\pm0.03\pm0.24)\times 10^{-3}$, where the first error is statistical and the second systematic.