Search for CP violation in ${D}_{(s)}^{+}$ → K⁻K⁺K⁺ decays

Abstract

A search for direct CP violation in the Cabibbo-suppressed decay ${D}_s^{+}$ → K⁻K⁺K⁺ and in the doubly Cabibbo-suppressed decay D⁺ → 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 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 ${D}_s^{+}$ → K⁻K⁺K⁺ decay and 31.6% for the D⁺ → K⁻K⁺K⁺ decay. No evidence for CP violation is observed in these decays.