Measurement of the f1(1285) → π+π−π0 decay

The isospin symmetry-breaking (ISB) decay f1(1285) → π+π−π0 has been studied at the VES facility. The branching ratio is measured: \(\frac{{BR\left( {f_1 \to \pi ^ + \pi ^ - \pi ^0 } \right)}} {{BR\left( {f_1 \to \eta \pi ^ + \pi ^ - } \right)}} = 0.86 \pm 0.16_{ - 0.20}^{ + 0.70} \%\) . An upper limit for the f1 decay into ρ(770)π is obtained: BR(f1(1285) → ρ+−π−+) < 0.31% at 95% CL.