PHYSICAL REVIEW D, cilt.96, sa.11, 2017 (SCI-Expanded)
Using a sample of 448.1 x 10(6) psi(3686) events collected with the BESIII detector, a search for the isospin violating decay eta(c) -> pi(+) pi(-) pi(0) via psi(3686) -> gamma eta(c) is presented. No signal is observed, and the upper limit on B(psi(3686) -> gamma eta(c)) x B(eta(c) -> pi(+) pi(-) pi(0)) is determined to be 1.6 x 10(-6) at the 90% confidence level. In addition, a search for eta(1405) -> f(0) (980) pi(0) in psi(3686) radiative decays is performed. No signal is observed, and the branching fraction B(psi(3686) -> gamma eta(1405)) x B(eta(1405) -> f(0)(980)pi(0)) x B(f(0)(980) -> pi(+)pi(-)) is calculated to be less than 5.0 x 10(-7) at the 90% confidence level.