G-parity breaking in ${\tau }^{-}\to {\eta }^{(\prime )}{\pi }^{-}{\nu }_{\tau }$ decays induced by the ${\eta }^{(\prime )}\gamma \gamma$ form factor

G. Hernández-Tomé, G. López Castro, P. Roig

Breaking of G-parity or new weak (second class) currents can be responsible for ${\tau }^{-}\to {\eta }^{(\prime )}{\pi }^{-}{\nu }_{\tau }$ decays. Forthcoming measurements of $\tau$ lepton properties at the Bell…