Study of an anomalous tau lepton decay using a chiral Lagrangian with vector mesons

The hadronic tau decay τ−→ντηπ−π0 occurs through V-A weak current. In this decay mode, the vector current contribution is intrinsic parity violating and the axial current contribution is G parity violating. The latter contribution is suppressed due to tiny isospin breaking. We have computed both vector and axial vector form factors using a chiral Lagrangian with vector mesons including the effect of isospin breaking and intrinsic parity violation. A numerical result of the invariant mass distribution is shown and the structure of ρ resonance can be seen in the distribution with respect to Mπ−π0.