Rare $\Xi^{0}$ decays: new results from NA48

The NA48 Collaboration has investigated rare decays of the $\Xi^{0}$ hyperon. Using data collected during a special high intensity run at the end of 1999, we determined the following preliminary branching fractions of the weak radiative decays to $\Lambda\gamma$ and $\Sigma^{0}\gamma:$ Br$(\Xi^{0} \to \Lambda\gamma) = (1.9 \pm 0.1 \pm 0.2) \times 10^{-3}$ and Br$(\Xi^{0} \to \Sigma^{0}\gamma ) = (3.7 \pm 0.5) \times 10^{-3}$ . In addition, we report on the observation of the beta decay and a search for the $\Delta S = 2$ transition $\Xi^{0} \to p\pi^{-}$.