D-meson lifetimes have been determined from decays observed in an exposure of the high resolution hydrogen bubble chamber LEBC in association with the European Hybrid Spectrometer (EHS) to an incident 360 GeV π− beam. Various techniques for lifetime determination are presented and the results compared. A new model-independent analysis based on the distribution in transverse decay length is introduced and preferred over other techniques. Best values are found to be:
$$\begin{gathered} \tau (D^0 ) = \left( {4.1_{ - 0.3}^{ + 0.7} } \right) \times 10^{ - 13} s (60 decays) \hfill \tau (D^ \pm ) = \left( {10.7_{ - 1.8}^{ + 2.8} } \right) \times 10^{ - 13} s (40 decays) \hfill \end{gathered} $$
. The lifetime ratio is:
$$T = \frac{{\tau (D^ \pm )}}{{\tau (D^0 )}} = 2.6_{ - 0.6}^{ + 0.8} $$
.
