Lifetime of theτ+Meson

$K^{+}$ meson lifetime measurements by counter techniques have been extended to include the ${\tau }^{+}$ or ${K_{\pi }}^{+}$ meson. A maximum-likelihood analysis of the data yields a mean life of (${11.7}_{-0.7\mathrm{}}^{+0.8\mathrm{}}$)×${10}^{-9\mathrm{}}$ sec. The previously reported mean life of the ${K_{\pi 2}}^{+}$ is (${12.1}_{-1.0\mathrm{}}^{+1.1\mathrm{}}$)×${10}^{-9\mathrm{}}$ sec. With 95% confidence the difference between the lifetimes of the two particles is less than 20% of their arithmetic mean.