τ decay and spin-one resonances

The implications of the recent measurement of the decay τ-→ντ bar Kππ are analyzed in the resonance dominance picture. With flavor SU(3) symmetry, the observed bar K1 resonance production in τ-→ντ bar Kππ requires τ-→ντa1- dominance in the nonstrange axial-vector channel. Then the spectral function sum rule cannot be saturated with ρ, π, and a1. The inclusion of the first excited vector meson brings back a consistent picture and improves the π+-π0 mass difference calculation