Precision Study of $η^\prime\rightarrowγπ^+π^-$ Decay Dynamics

Abstract

Using a low background data sample of $9.7\times10^{5}$ $Jψ\rightarrowγη^\prime$, $η^\prime\rightarrowγπ^+π^-$ events, which are 2 orders of magnitude larger than those from the previous experiments, recorded with the BESIII detector at BEPCII, the decay dynamics of $η^\prime\rightarrowγπ^+π^-$ are studied with both model-dependent and model-independent approaches. The contributions of $ω$ and the $ρ(770)-ω$ interference are observed for the first time in the decays $η^\prime\rightarrowγπ^+π^-$ in both approaches. Additionally, a contribution from the box anomaly or the $ρ(1450)$ resonance is required in the model-dependent approach, while the process specific part of the decay amplitude is determined in the model-independent approach.

7 pages, 4 figures, 1 tables