Observation of the doubly Cabibbo-suppressed decay $Xi_{c}^{+}to pphi$

The doubly Cabibbo-suppressed decay $Xi_{c}^{+}to pphi$ with $phito K^{+}K^{-}$ is observed for the first time, with a statistical significance of more than fifteen standard deviations. The data sample used in this analysis corresponds to an integrated luminosity of 2 fb$^{-1}$ recorded with the LHCb detector in $pp$ collisions at a centre-of-mass energy of 8 TeV. The ratio of branching fractions between the decay $Xi_{c}^{+}to pphi$ and the singly Cabibbo-suppressed decay $Xi_{c}^{+}to pK^{-}pi^{+}$ is measured to be begin{equation*} frac{mathcal{B}(Xi_{c}^{+}to pphi)}{mathcal{B}(Xi_{c}^{+}to pK^{-}pi^{+})} = (19.8 pm 0.7 pm 0.9 pm 0.2) times 10^{-3}, end{equation*} where the first uncertainty is statistical, the second systematic and the third due to the knowledge of the $phito K^{+}K^{-}$ branching fraction.