Resonance Chiral Lagrangian analysis of τ -→η(′)π-π0ν τ

Abstract

The hadronization structure of τ -→ηπ -π0ν τ decays is analyzed using chiral perturbation theory with resonances, considering only the contribution of the lightest meson resonances at leading order in the 1/N C expansion. After imposing the asymptotic behavior of vector spectral functions ruled by QCD, unknown effective couplings are determined by fitting the τ -→ηπ -π0ν τ branching ratio and decay spectrum to recent data. Predictions for the partner decay τ -→η ′π -π0ν τ and the low-energy behavior of the cross section σ(e +e -→ηπ +π -) are also discussed. © 2012 American Physical Society.