Measurement of the CKM angle $\gamma$ from a combination of $B\to DK$ analyses

A combination is made of tree-level measurements of the CKM angle $\gamma$ from $B \to DK$ decays at LHCb. The results are obtained from time-integrated analyses of $B^{+}\to D K^+$, $B^0\to D K^{*0}$ and $B^+ \to D K^+\pi^+\pi^-$ decays, where the $D$ meson decays into $K^+K^-$, $\pi^+\pi^-$, $K^+K^-\pi^0$, $K^\pm\pi^\mp\pi^0$, $\pi^+\pi^-\pi^0$, $K^\pm \pi^\mp$, $K^0_S K^\pm\pi^\mp$, $K^0_S\pi^+\pi^-$, $K^0_S K^+K^-$, $K^\pm\pi^\mp \pi^+\pi^-$ and $\pi^+\pi^-\pi^+\pi^-$ final states. In addition, results obtained from a time-dependent analysis of $B_s^0 \to D_s^\mp K^\pm$ decays are included. The combination gives a best fit value of $\gamma = 70.9^\circ$ and confidence intervals are set using a frequentist procedure: $\gamma \in [62.4,78.0]^\circ$ at 68$\%$ CL and $\gamma \in [51.0,85.0]^\circ$ at 95$\%$ CL, where all values are modulo $180^\circ$. Using the best fit value and the 68$\%$ CL interval, $\gamma$ is measured to be \begin{align*} \gamma = (70.9\,^{+7.1}_{-8.5})^\circ\,, \end{align*} where the quoted uncertainty includes the statistical and systematic combined. This is the most precise single-experiment measurement of the CKM angle $\gamma$ to date.