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Regular version of the site

Article

“Measurement of the CKM angle gamma from a combination of B->Dh analyses"

Derkach D., Aaij R.

A combination of three LHCb measurements of the CKM angle $\gamma$ is presented. The decays $B^\pm\to DK^\pm$ and $B^\pm\to D\pi^\pm$ are used, where $D$ denotes an admixture of $D^0$ and $\overline{D^0}$ mesons, decaying into $K^+K^-$, $\pi^+\pi^-$, $K^\pm \pi^\mp$, $K^\pm \pi^\mp \pi^\pm \pi^\mp$, $K_S\pi^+\pi^-$, or $K_S K^+K^-$ final states. All measurements use a dataset corresponding to 1.0 fb$^{-1}$ of data. Combining results from $B^\pm\to DK^\pm$ decays alone a best-fit value of $\gamma = 72.0^\circ$ is found, and confidence intervals are set \begin{align*} \gamma \in [56.4,86.7]^\circ \quad &{\rm at\ 68\%\,CL}\,,\\ \gamma \in [42.6,99.6]^\circ \quad &{\rm at\ 95\%\,CL}\,. \end{align*} The best-fit value of $\gamma$ found from a combination of results from $B^\pm\to D\pi^\pm$ decays alone, is $\gamma = 18.9^\circ$, and the confidence intervals \begin{align*} \gamma \in [7.4,99.2]^\circ \quad \cup \quad [167.9,176.4]^\circ \quad &{\rm at\ 68\%\,CL}\, \end{align*} are set, without constraint at $95\%$ CL. The combination of results from $B^\pm\to DK^\pm$ and $B^\pm\to D\pi^\pm$ decays gives a best-fit value of $\gamma = 72.6^\circ$ and the confidence intervals \begin{align*} \gamma \in [55.4,82.3]^\circ \quad &{\rm at\ 68\%\,CL}\,,\\ \gamma \in [40.2,92.7]^\circ \quad &{\rm at\ 95\%\,CL}\, \end{align*} are set. All values are expressed modulo $180^\circ$, and are obtained taking into account the effect of $D^0$--$\overline{D^0}$ mixing.