Limits on D0-D0bar Mixing and CP Violation from the Ratio of Lifetimes for Decay to K-pi+, K-K+, and pi-pi+

TL;DR

This paper measures $D^0$-$ar{D}^0$ mixing and CP violation parameters using lifetime ratios from various decay modes, providing constraints on mixing parameters with data from the BaBar detector.

Contribution

First measurement of $D^0$-$ar{D}^0$ mixing parameters using lifetime ratios from multiple decay channels with a large data sample.

Findings

Measured mixing parameter $Y = (0.8 extpm 0.4 ext{(stat.)} ^{+0.5}_{-0.4} ext{(syst.)}) ext{ extperthousand}$

CP-violation parameter $ riangle Y = (-0.8 extpm 0.6 ext{(stat.)} extpm 0.2 ext{(syst.)}) ext{ extperthousand}$

Results consistent with no CP violation and provide limits on mixing parameters.

Abstract

We present a measurement of $D^0$-$\D0bar$ mixing parameters using the ratios of lifetimes extracted from samples of $D^0$ mesons decaying to $K^-\pi^+$, $K^-K^+$, and $\pi^-\pi^+$. Using 91 ${\rm fb}^{-1}$ of data collected by the BaBar detector at the PEP-II asymmetric-energy $B$ Factory, we obtain a value $Y = (0.8 \pm 0.4 ({\rm stat.}) {}^{+0.5}_{-0.4} ({\rm syst.}))$%, which, in the limit of CP conservation, corresponds to the mixing parameter $y = \Delta\Gamma/2\Gamma$. Using the difference in lifetimes of $D^0$ and $\D0bar$ mesons, we obtain the CP-violation parameter $\Delta Y = (-0.8 \pm 0.6 ({\rm stat.}) \pm 0.2 ({\rm syst.}))$%.