Long-Distance Contributions to D^0-D^0bar Mixing Parameters

Abstract

Long-distance contributions to the $D^0$-${\bar{D}}^0$ mixing parameters $x$ and $y$ are evaluated using latest data on hadronic $D^0$ decays. In particular, we take on two-body $D\to PP$ and $VP$ decays to evaluate the contributions of two-body intermediate states because they account for $\sim 50$ of hadronic $D^0$ decays. Use of the diagrammatic approach has been made to estimate yet-observed decay modes. We find that $y$ is of order a few $\times 10^{-3}$ and $x$ of order $10^{-3}$ from hadronic $PP$ and $VP$ modes. These are in good agreement with the latest direct measurement of $D^0$-${\bar{D}}^0$ mixing parameters using the $D^0\to K_S{\pi }^{+}{\pi }^{-}$ and $K_S{K}^{+}{K}^{-}$ decays by BaBar. We estimate the contribution to $y$ from the $VV$ modes using the factorization model and comment on the single-particle resonance effects and contributions from other two-body modes involving even-parity states.

Comments: 18 pages and 1 figure; footnotes and references added; to appear in Phys. Rev. D