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 ^± 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°, 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° is obtained, which is one of the most precise determinations of γ to date.