Search for $CP$ violation in $D_{(s)}^{+}\to K^{-}{K}^{+}{K}^{+}$ decays

A search for direct $CP$ violation in the Cabibbo-suppressed decay $D_s^{+}\to K^{-}{K}^{+}{K}^{+}$ and in the doubly Cabibbo-suppressed decay $D^{+}\to K^{-}{K}^{+}{K}^{+}$ is reported. The analysis is performed with data collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 5.6 ${\text{fb}}^{-1}$. The search is conducted by comparing the $D_{(s)}^{+}$ and $D_{(s)}^{-}$ Dalitz-plot distributions through a model-independent binned technique, based on fits to the $K^{-}{K}^{+}{K}^{+}$ invariant-mass distributions, with a total of 0.97 (1.27) million $D_s^{+}$ ($D^{+}$) signal candidates. The results are given as $p$-values for the hypothesis of $CP$ conservation and are found to be 13.3% for the $D_s^{+}\to K^{-}{K}^{+}{K}^{+}$ decay and 31.6% for the $D^{+}\to K^{-}{K}^{+}{K}^{+}$ decay. No evidence for $CP$ violation is observed in these decays.