Psi(2S) two- and three-body hadronic decays

TL;DR

This paper reports new measurements of decay branching fractions of psi(2S) into various hadronic final states, comparing them with J/psi decays to test the 12% rule in charmonium decays.

Contribution

First measurements of several psi(2S) decay modes and updated results for some channels, providing data to test charmonium decay models and the 12% rule.

Findings

Branching fractions for b1 pi and omega f2(1270) are updated.

Most ratios of psi(2S) to J/psi decays are smaller than the 12% rule predicts.

Some decay channels are consistent with the 12% rule within errors.

Abstract

We report measurements of branching fractions for psi(2S) decays into omega pi pi, b1 pi,omega f2(1270),omega KK, omega p pbar, phi pi pi, phi f0(980),phi KK, and an upper limit for phi p pbar final states based on a data sample of 4 X 10^6 psi(2S) events collected with the BESI detector at the Beijing Electron-Positron Collider. The branching fractions for b1 pi and omega f2(1270) update previous BES results, while those for other decay modes are first measurements. The ratios of psi(2S)and J/psi branching fractions are smaller than what is expected from the 12% rule by a factor of five for omega f2(1270),by a factor of two for omega pi pi, omega p pbar, and phi KK, while for other studied channels the ratios are consistent with expectation within errors.