Determining the unitarity triangle angle $\gamma$ with a four-body   amplitude analysis of $\rm B^\pm \to (K^+K^-\pi^+\pi^-)_D K^\pm$ decays
  We explain how a four-body amplitude analysis of the $\rm D$ decay products in the mode $\rm B^\pm \to (K^+K^-\pi^+\pi^-)_D K^\pm$ is sensitive to the unitarity triangle angle $\gamma$. We present results from simulation studies which show that a precision on $\gamma$ of $15^\circ$ is achievable with 1000 events and assuming a value of 0.10 for the parameter $r_B$. 
J. Rademacker, G. Wilkinson