Pseudoscalar mass effects in the decays of τ with three pseudoscalar mesons

We study the dynamical effects of nonvanishing pseudoscalar masses in τ decays into three mesons. The hadronic matrix elements are obtained by using the chiral Lagrangian of the order O(${\mathit{P}}^2$), including the quark mass terms which explicitly break the chiral symmetry, and implementing the low-lying resonances in the different channels. We demonstrate that suitable angular distributions are sensitive to the nonconservation of the axial-vector current resulting from the pseudoscalar masses. Numerical results for the relevant structure functions are given for the decay modes τ→ν${\mathrm{\pi }}^{\mathrm{-}}$ ${\mathrm{\pi }}^{\mathrm{-}}$ ${\mathrm{\pi }}^{+}$, ν${\mathit{K}}^{\mathrm{-}}$ ${\mathrm{\pi }}^{\mathrm{-}}$ ${\mathrm{\pi }}^{+}$, and ν${\mathit{K}}^{\mathrm{-}}$ ${\mathrm{\pi }}^{\mathrm{-}}$ ${\mathit{K}}^{+}$.