Experimental study of psi' decays to K+K- pi^0 and K+K- eta

TL;DR

This study measures branching fractions of psi' decays to specific kaon and eta final states, discovering a new decay mode that challenges existing helicity rules and testing QCD predictions.

Contribution

First observation of the decay $ o K_2^{*}(1430)^+K^-+c.c.$ in psi' decays, providing new data to test QCD and helicity rule violations.

Findings

First measurement of $ o K_2^{*}(1430)^+K^-+c.c.$ branching fraction

Observation of helicity rule violation in $ o K_2^{*}(1430)^+K^-+c.c.$ decay

Branching fractions measured for multiple psi' decay modes

Abstract

Using $(106\pm4)\times 10^6$ $\psip$ events accumulated with the BESIII detector at the BEPCII $e^+e^-$ collider, we present measurements of the branching fractions for psi' decays to $K^{+}K^{-}\pi^{0}$ and $K^{+}K^{-}\eta$. In these final states, the decay $\psi'\to K_2^{*}(1430)^+K^-+c.c.$ is observed for the first time, and its branching fraction is measured to be $(7.12\pm{0.62}{\rm (stat.)}^{+1.13}_{-0.61}{\rm (syst.)})\times 10^{-5}$, which indicates a violation of the helicity selection rule in $\psip$ decays. The branching fractions of $\psi'\to K^*(892)^+K^-+c.c., \phi\eta, \phi\pi^0$ are also measured. The measurements are used to test the QCD predictions on charmonium decays.