Observation of p pbar pi^0 and p pbar eta in psi' decays

TL;DR

This study measures the decay rates of psi' particles into proton-antiproton pairs with pi^0 and eta mesons, providing new precise data and first observations for these decay channels.

Contribution

The paper reports the first observation of psi' decaying into p pbar eta and improves the measurement of psi'-->p pbar pi^0 branching fraction.

Findings

psi'-->p pbar pi^0 branching fraction: (13.2±1.0±1.5)×10^{-5}

psi'-->p pbar eta observed for the first time with branching fraction: (5.8±1.1±0.7)×10^{-5}

Enhanced precision in measuring psi' decay channels

Abstract

The processes psi'-->p pbar pi^0 and psi'-->p pbar eta are studied using a sample of 14 million psi' decays collected with the Beijing Spectrometer at the Beijing Electron-Positron Collider. The branching fraction of psi'-->p pbar pi^0 is measured with improved precision as (13.2\pm 1.0\pm 1.5)\times 10^{-5}, and psi'-->p pbar eta is observed for the first time with a branching fraction of (5.8\pm 1.1\pm 0.7)\times 10^{-5}, where the first errors are statistical and the second ones are systematic.