Study of the τ-→3h-2h+ντ decay

The branching fraction of the τ-→3h-2h+ντ decay (h=π,K) is measured with the BABAR detector to be (8.56±0.05±0.42) ×10-4, where the first error is statistical and the second systematic. The observed structure of this decay is significantly different from the phase space prediction, with the ρ resonance playing a strong role. The decay τ-→f1(1285)π-ντ, with the f1(1285) meson decaying to four charged pions, is observed and the branching fraction is measured to be (3.9±0.7±0.5)×10-4. © 2005 The American Physical Society.