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$τ^-\toπ^-η^{(\prime)}ν_τ$ decays

The vector and scalar form factors relevant to the second-class current $τ^-\toπ^-η^{(\prime)}ν_τ$ processes are evaluated supplementing Chiral Perturbation Theory with the inclusion of resonances as explicit degrees of freedom. While the vector contribution is essentially fixed from knowledge of the two-pion vector form factor, the scalar form factor demands a coupled channel dispersive analysis to obtain robust predictions for the detection of these decay modes.