Search for CP violation in D(s)+ → K ⁻ K ⁺ K ⁺ decays

A search for direct CP violation in the Cabibbo-suppressed decay Ds+ → 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 Ds+ (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 Ds+ → K ⁻ K ⁺ K ⁺ decay and 31.6% for the D ⁺ → K ⁻ K ⁺ K ⁺ decay. No evidence for CP violation is observed in these decays. [Figure not available: see fulltext.]