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 − ] D h ± and B ± → [ π + π − π + π − ] D h ± 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 $\gamma ={\left(53.{9}_{-8.9}^{+9.5}\right)}^{{}^{\circ}}$ , 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 $\gamma ={\left(52.{6}_{-6.4}^{+8.5}\right)}^{{}^{\circ}}$ is obtained, which is one of the most precise determinations of γ to date.