Determine the branching fraction of ηc → 2(π+π−)π0

Determine the branching fraction of the hadronic decay ηc → 2(π+π−)π0 to resolve its currently unknown value, which is needed for precise estimation of peaking backgrounds and systematic uncertainties in analyses of hc decays such as hc → 2(π+π−)π0η produced via ψ(3686) → π0hc.

Background

In the analysis of ψ(3686) → π0hc with subsequent decays hc → 2(π+π−)π0η and related modes, the authors identify peaking backgrounds arising from hc → γηc followed by ηc decays. Accurate modeling of these backgrounds requires knowledge of the branching fractions of the relevant ηc decay channels.

The paper explicitly notes that the branching fraction of ηc → 2(π+π−)π0 is currently unknown, and this lack of information is incorporated into their systematic uncertainty treatment. Determining this branching fraction would reduce uncertainties in the measurement of hc decay modes reported in the paper.