A Measurement of the Branching Fraction $\mathcal{B}{\tau }^{+}\to h^{-}{\pi }^0{\nu }_{\tau }$

Using data from the CLEO II detector at CESR, we measure ${\cal B}(\tau^\pm\rightarrow h^\pm\pi^0\nu_\tau)$where$h^\pm$referstoeither$\pi^\pm$or$K^\pm$. We use three different methods to measure this branching fraction. The combined result is ${\cal B}(\tau^\pm\rightarrow h^\pm\pi^0\nu_\tau) = 0.2587 \pm 0.0012 \pm 0.0042$, in good agreement with Standard Model predictions. This result, in combination with other precision measurements, reduces the significance of the one-prong problem in tau decays. A postscript version is available through World-Wide-Web in http://w4.lns.cornell.edu/public/CLNS/1994/