Observation of Thirteen New Exclusive Multi-Body Hadronic Decays of the $\psi(2S)$

TL;DR

This paper reports the first measurements of branching fractions for 13 new decay modes of the psi(2S) particle, along with more precise data for 8 known modes, testing theoretical predictions like the 12% rule.

Contribution

It provides the first measurements of several psi(2S) decay modes and refines existing data, offering new insights into charmonium decay processes.

Findings

First measurements of 13 psi(2S) decay modes.

More precise data for 8 previously known modes.

Comparison with J/psi decays tests the 12% rule.

Abstract

Using data accumulated with the CLEO detector corresponding to an integrated luminosity of 5.63 pb^-1 on the peak of the psi(2S) and 20.70 pb^-1 continuum at 3.67 GeV, we report first measurements of the branching fractions for the following 13 decay modes of the psi(2S): eta 3pi, eta^\prime 3pi, rho K^+K^-, K^+K^-pi^+pi^-pi^0, 2(K^+K^-), 2(K^+K^-)pi^0, rho p \bar p, p \bar p pi^+pi^-pi^0, eta p \bar p, p \bar p K^+K^-, Lambda \bar Lambda pi^+pi^-, Lambda \bar p K^+, Lambda \bar p K^+pi^+pi^-, and more precise measurements of 8 previously measured modes: 2(pi^+pi^-), rho pi^+pi^-, 2(pi^+pi^-)pi^0, omega pi^+pi^-, K^+K^-pi^+pi^-, omega K^+K^-, phi K^+K^-, p \bar p pi^+pi^-. We also report new branching fraction measurements of phi pi^+pi^- and omega p \bar p and upper limits for eta pi^+pi^-, eta K^+K^- and phi p \bar p. Results are compared, where possible, with the corresponding J/psi branching ratios to provide new tests of the 12% rule.