A model-independent measurement of the CKM angle γ in the decays B^± → [K⁺K⁻π⁺π⁻]_Dh^± and B^± → [π⁺π⁻π⁺π⁻]_Dh^± (h = K, π)

A model-independent determination of the CKM angle γ is presented, using the B^± → [K⁺K⁻π⁺π⁻]_Dh^± and B^± → [π⁺π⁻π⁺π⁻]_Dh^± (h = K, π) decays, with h = K, π. This measurement is the first phase-space binned study of these decay modes, and uses a sample of proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb⁻¹. The phase-space bins are optimised for sensitivity to γ, and in each bin external inputs from the BESIII experiment are used to constrain the charm strong-phase parameters. The result of this binned analysis is γ = (53.9_-8.9^+9.5)^º, where the uncertainty includes both statistical and systematic contributions. Furthermore, when combining with existing phase-space integrated measurements of the same decay modes, a value of γ = (52.6_-6.4^+8.5)^º is obtained, which is one of the most precise determinations of γ to date.