Search for psi(2S)--> eta_c pi^+ pi^- pi^0

TL;DR

This study searched for a specific decay of the psi(2S) particle into eta_c and pions, using data from CLEO detectors, but found no signal and set an upper limit below theoretical predictions.

Contribution

First experimental search for psi(2S) -> eta_c pi+ pi- pi0 decay testing a specific theoretical model, setting a new upper limit on its branching fraction.

Findings

No signal observed for the decay.

Upper limit on branching fraction is < 1.0 x 10^-3.

Result is an order of magnitude below theoretical expectation.

Abstract

Using 5.63 pb^-1 of data accumulated at the psi(2S) resonance with the CLEO III and CLEO-c detectors corresponding to 3.08 million psi(2S) decays, a search is performed for the decay psi(2S) -> eta_c pi^+pi^-pi^0 to test a theoretical prediction based upon the assumption that the c \bar c pair in the psi(2S) does not annihilate directly into three gluons but rather survives before annihilating. No signal is observed, and a combined upper limit from six eta_c decay modes is determined to be B(psi(2S) -> eta_c pi^+pi^-pi^0) < 1.0 x 10^-3 at 90% C.L. This upper limit is about an order of magnitude below the theoretical expectation.