Update of the LHCb combination of the CKM angle $\gamma$ using $B\to DK$ decays

A combination of tree-level measurements of the CKM angle $\gamma$ from $B \to DK$ decays at LHCb is performed. The results are obtained from time-integrated measurements of $B^+\to D K^+$, $B^+ \to D^* K^+$, $B^+ \to D K^{*+}$, $B^0 \to D K^{*0}$, $B^0 \to D K^+ \pi^-$ and $B^+ \to D K^+ \pi^+ \pi^-$ decays. In addition, inputs from a time-dependent analysis of \BsDsK decays are included. This combination uses both new and updated results compared to an earlier LHCb combination, and gives a best fit value of $\gamma = 76.8^\circ$ with confidence intervals, set using a frequentist procedure, of $\gamma \in [71.1,81.9]^\circ$ at 68.3 % confidence level (CL) and $\gamma \in [64.3,86.6]^\circ$ at 95.5 % CL, where all values are modulo $180^\circ$. Using the best fit value and the 68.3 % CL interval, $\gamma$ is measured to be \begin{align*} \gamma = (76.8\,^{+5.1}_{-5.7})^\circ\,, \end{align*} where the uncertainty includes statistical and systematic contributions. This is the most precise measurement of the CKM angle $\gamma$ to date.