Observation of $\mathit{B}\to {\mathit{K}}^{\pm }{\pi }^0$ and $\mathit{B}\to {\mathit{K}}^0{\pi }^0$, and Evidence for $\mathit{B}\to {\pi }^{+}{\pi }^{-}$

We have studied charmless hadronic decays of $B$ mesons into two-body final states with kaons and pions and observe three new processes with the following branching fractions: $B(B\to {\pi }^{+}{\pi }^{-})=({4.3}_{-1.4\mathrm{}}^{+1.6\mathrm{}}\pm 0.5)\times {10}^{-6\mathrm{}}$, $B(B\to K^0{\pi }^0)=\left({14.6}_{-5.1-3.3\mathrm{}}^{+5.9+2.4\mathrm{}}\right)\times {10}^{-6\mathrm{}}$, and $B(B\to K^{\pm }{\pi }^0)=\left({11.6}_{-2.7-1.3\mathrm{}}^{+3.0+1.4\mathrm{}}\right)\times {10}^{-6\mathrm{}}$. We also update our previous measurements for the decays $B\to K^{\pm }{\pi }^{\mp }$ and $B^{\pm }\to K^0{\pi }^{\pm }$.