Measurement of CP Observables in $B^- \rightarrow D^0 K^- \pi^+ \pi^-$ Decays

The analysis of the 3 fb$^{-1}$ data set collected by the LHCb experiment in 2011 and 2012 located at the LHC, CERN, Geneva, Switzerland is presented. The data set is comprised of one third taken at center of mass energy $\sqrt{s} = 7$ TeV and the remaining two thirds taken at $\sqrt{s} = 8$ TeV. The data is analyzed for the decays $B^-\to D^0 K^- \pi^+ \pi^-$ and $B^- \to D^0 \pi^- \pi^+\pi^-$, with the $D^0 \rightarrow K^+\pi^-, K^+K^-, \pi^+\pi^- \text{ or } K^-\pi^+$. The $CP$ violation sensitive observables $R_{CP+}$, $A_{CP+}$, and $R_{d,s}^\pm$ are measured, which are sensitive to the CKM Angle $\gamma$. Upper limits are reported for the values of $R_s^\pm$ since the doubly Cabibbo suppressed decay $B^- \to D^0K^-\pi^+\pi^-$ with $D^0 \to K^+\pi^-$ is not observed.