Search for D0D0bar Mixing and a Measurement of the Doubly Cabibbo-suppressed Decay Rate in D0 -> K pi Decays

TL;DR

This study searches for $D^0$-$ar{D}^0$ mixing and measures the rate of doubly Cabibbo-suppressed decays in $D^0 o K ext{pi}$, finding results compatible with no mixing or CP violation within current experimental sensitivity.

Contribution

First measurement of $D^0$-$ar{D}^0$ mixing parameters and decay rates using 57.1 fb$^{-1}$ of data from the BABAR detector, setting limits on mixing and CP violation.

Findings

No evidence for mixing or CP violation detected.

Upper limit on mixing rate $R_M < 0.16 ext{%}$.

Measured decay rate $R_D = (0.357 ext{±} 0.022 ext{(stat.)} ext{±} 0.027 ext{(syst.)}) ext{%}.

Abstract

We present results of a search for $D^0$-$\kern 0.2em\bar{\kern -0.2em D}{}^0$~mixing and a measurement of $R_{\rm D}$, the ratio of doubly Cabibbo-suppressed decays to Cabibbo-favored decays, based on an analysis of $D^0 \to K^{+}\pi^{-}$ decays in 57.1~${fb}^{-1}$ of data collected at or just below the $\Upsilon{(4S)}$ resonance with the {\slshape BABAR} detector at the PEP-II collider. Our results are compatible with no mixing and no $CP$ violation. At the 95% C.L., allowing for CP violation, we find the mixing parameters ${x^{\prime}}^2<0.0022$ and $-0.056<y^{\prime}<0.039$, and the mixing rate $R_{\rm M} < 0.16%$. In the limit of no mixing, $R_{\rm D} = (0.357 \pm 0.022 \hbox{(stat.)} \pm 0.027 \hbox{(syst.)})%$ and the $CP$~violating asymmetry \mbox{$A_{\rm D} = 0.095 \pm 0.061 \hbox{(stat.)} \pm 0.083 \hbox{(syst.)}$.}