A Measurement of Lifetime Difference in $D^0$ Meson Decays

Abstract

We report a measurement of the $D^0$-$\bar{D}{}^0$ mixing parameter $y_{CP}$ using 23.4 fb${}^{-1}$ of data collected near the ${\rm Y}$(4S) resonance with the Belle detector at KEKB. $y_{CP}$ is measured from the lifetime difference of $D^0$ mesons decaying into the $K^{-}{\pi }^{+}$ state and the CP even eigenstate $K^{-}{K}^{+}$. We find $y_{CP}=(-0.5\pm 1.0{}_{-0.8}^{+0.7})\times 10^{-2}$, where the first error is statistical and the second systematic, corresponding to a 95% confidence interval $-0.030<y_{CP}<0.020$.

10 pages, 3 figures