Study of $B^\pm \to \pi^\pm \pi^\mp \pi^\pm$ at Belle

Decays of B mesons to three-body charmless final states probe the properties of the weak interaction through their dependence on the complex quark couplings in the CKM matrix. They also test dynamical models for hadronic B decays. Based on a sample of $ (771.581\pm 10.566) \times 10^6 $ $B\bar B$ pairs collected by the Belle experiment at $\sqrt{s} = 10.58 GeV$, we present a study of direct CP nonconservation in $B^\pm \to \pi^\pm \pi^+ \pi^-$.