Measurement of $D^0$ decays to $K_L^0{\pi }^0$ and $K_S^0{\pi }^0$ at Belle

Abstract

We present a preliminary measurement of the ratio of $D^0$ decay rates into $K_L^0{\pi }^0$ and $K_S^0{\pi }^0$ final states. This ratio can be used to disentangle the Cabibbo favored $D^0\to {\bar{K}}^0{\pi }^0$ and doubly Cabibbo suppressed $D^0\to K^0{\pi }^0$ amplitudes, and contributes to the important goal of constraining the strong phase ${\delta }_{K\pi }$ between $D^0\to K^{-}{\pi }^{+}$ and $D^0\to K^{+}{\pi }^{-}$. The measurement is based on a large data set accumulated by the Belle detector at the KEKB $e^{+}{e}^{-}$ collider, with $K_L^0$ candidates reconstructed using hadronic clusters in the KLM ($K_L$ and $\mu$ identification system), together with a $D^0$ mass constraint and $D^{\ast +}$ tag.

Paper submitted to the 2001 Lepton Photon Conference. Version 31-Jul-2001: REVTeX4 formatting problem fixed