Measurement of theD0andD+lifetimes

We have used a high-resolution drift chamber in the Mark II detector at the SLAC $e^{+}$ $e^{\mathrm{-}}$ storage ring PEP to measure the lifetimes of the $D^0$ and $D^{+}$ mesons produced in $e^{+}$ $e^{\mathrm{-}}$ annihilations at 29 GeV. Based on a sample of 74 decays for the $D^0$ mesons and 23 decays for the $D^{+}$ mesons, the lifetimes are found to be &${=(4.7\mathrm{}}_{\mathrm{-}0.8}^{+0.9\mathrm{}}$) ±0.5×${10}^{\mathrm{-}13}$ sec and &${=(8.9\mathrm{}}_{\mathrm{-}2.7}^{+3.8\mathrm{}}$) ±1.3×${10}^{\mathrm{-}13}$ sec. This leads to a ratio of lifetimes &${=1.9\mathrm{}}_{\mathrm{-}0.7}$ ${}_{}{}^{+0.9\mathrm{}}{}_{}{}^{}0.3$. .AE