First observation of Cabibbo-suppressed<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msubsup><mml:mi>Ξ</mml:mi><mml:mi>c</mml:mi><mml:mn>0</mml:mn></mml:msubsup></mml:math>decays
First observation of Cabibbo-suppressed<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msubsup><mml:mi>Ξ</mml:mi><mml:mi>c</mml:mi><mml:mn>0</mml:mn></mml:msubsup></mml:math>decays
We report the first observation of the Cabibbo-suppressed decays ${\ensuremath{\Xi}}_{c}^{0}\ensuremath{\rightarrow}{\ensuremath{\Xi}}^{\ensuremath{-}}{K}^{+}$, ${\ensuremath{\Xi}}_{c}^{0}\ensuremath{\rightarrow}\ensuremath{\Lambda}{K}^{+}{K}^{\ensuremath{-}}$ and ${\ensuremath{\Xi}}_{c}^{0}\ensuremath{\rightarrow}\ensuremath{\Lambda}\ensuremath{\phi}$, using a data sample of $711\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected at the $\ensuremath{\Upsilon}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. We measure the ratios of branching fractions to be $\frac{\mathcal{B}({\ensuremath{\Xi}}_{c}^{0}\ensuremath{\rightarrow}{\ensuremath{\Xi}}^{\ensuremath{-}}{K}^{+})}{\mathcal{B}({\ensuremath{\Xi}}_{c}^{0}\ensuremath{\rightarrow}{\ensuremath{\Xi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+})}=(2.75\ifmmode\pm\else\textpm\fi{}0.51\ifmmode\pm\else\textpm\fi{}0.25)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}$, $\frac{\mathcal{B}({\ensuremath{\Xi}}_{c}^{0}\ensuremath{\rightarrow}\ensuremath{\Lambda}{K}^{+}{K}^{\ensuremath{-}})}{\mathcal{B}({\ensuremath{\Xi}}_{c}^{0}\ensuremath{\rightarrow}{\ensuremath{\Xi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+})}=(2.86\ifmmode\pm\else\textpm\fi{}0.61\ifmmode\pm\else\textpm\fi{}0.37)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}$ and $\frac{\mathcal{B}({\ensuremath{\Xi}}_{c}^{0}\ensuremath{\rightarrow}\ensuremath{\Lambda}\ensuremath{\phi})}{\mathcal{B}({\ensuremath{\Xi}}_{c}^{0}\ensuremath{\rightarrow}{\ensuremath{\Xi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+})}=(3.43\ifmmode\pm\else\textpm\fi{}0.58\ifmmode\pm\else\textpm\fi{}0.32)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}$, where …