Study of τ Decays to Six Pions and a Neutrino

The $\tau$ decays to six-pion final states have been studied with the CLEO detector at the Cornell Electron Storage Ring. The measured branching fractions are $B({\tau }^{-}\to 2{\pi }^{-}{\pi }^{+}3{\pi }^0{\nu }_{\tau })=(2.2\pm 0.3\pm 0.4)\times 10^{-4\mathrm{}}$ and $B({\tau }^{-}\to 3{\pi }^{-}2{\pi }^{+}{\pi }^0{\nu }_{\tau })=(1.7\pm 0.2\pm 0.2)\times 10^{-4\mathrm{}}$. A search for substructure in these decays shows that they are saturated by intermediate states with $\eta$ or $\omega$ mesons. We present the first observation of the decay ${\tau }^{-}\to 2{\pi }^{-}{\pi }^{+}\omega {\nu }_{\tau }$ and the branching fraction is measured to be $(1.2\pm 0.2\pm 0.1)\times {10}^{-4\mathrm{}}$. The measured branching fractions are in good agreement with the isospin expectations but somewhat below the conserved-vector-current predictions.