Search for a Lifetime Difference in D⁰ Decays

The D^0 mixing parameter y = Delta Gamma/2 Gamma was determined by measuring the D^0 lifetime separately for the K^-pi^+ decay mode and the K^-K^+ decay mode with 12.4 fb^{-1} of data collected by the BABAR experiment in 2001. Backgrounds were suppressed with the D^* --> D^0pi^+ decay and particle identification. The following preliminary result was obtained: y = (-1.0 +/- 2.2 (stat) +/- 1.7 (syst))%.