Improved constraints on $\gamma$ from $B^\pm\to DK^\pm$ decays including first results on 2012 data

Preliminary results for the CKM angle $\gamma$ are presented, from a combination of measurements using $B^\pm\to DK^\pm$ decays, where $D$ denotes an admixture of $D^0$ and $\overline{D}^0$ mesons. Results for the $D$ final states $K^+K^-$, $\pi^+\pi^-$, $K^\pm \pi^\mp$, and $K^\pm \pi^\mp \pi^\pm \pi^\mp$ are based on a dataset corresponding to $1\,{\rm fb}^-1$ of integrated luminosity recorded at $\sqrt{s}=7\,{\rm TeV}$ in 2011. Results for the $D$ decays into $K_S\pi^+\pi^-$ and $K_S K^+K^-$ are based on a dataset corresponding to $3\,{\rm fb}^{-1}$ recorded at $\sqrt{s}=7$ and $8\,{\rm TeV}$ in 2011 and 2012, respectively. A best fit value of $\gamma = 67.2^\circ$ is found, and confidence intervals are set: \begin{align*} \gamma \in [55.1, 79.1]^\circ &~{\rm at~68\%~CL}\,,\\ \gamma \in [43.9, 89.5]^\circ &~{\rm at~95\%~CL}\,, \end{align*} where the first interval is translated into $\gamma = (67 \pm 12)^\circ$ at 68 % CL, and all quoted values are modulo $180^\circ$.