We report measurements of the branching fractions for $B^0\to {\pi }^{+}{\pi }^{-}$, $K^{+}{\pi }^{-}$, $K^{+}{K}^{-}$, and $K^0{\pi }^0$ and $B^{+}\to {\pi }^{+}{\pi }^0$, $K^{+}{\pi }^0$, $K^0{\pi }^{+}$, and $K^{+}{\overline{K}}^0$, based on $10.4{\mathrm{fb}}^{-1\mathrm{}}$ of data collected on the $\Upsilon \left(4S\right)$ resonance with the Belle detector. We find $B(B^0\to {\pi }^{+}{\pi }^{-})=\left({0.56}_{-0.20-0.05\mathrm{}}^{+0.23+0.04\mathrm{}}\right)\times {10}^{-5\mathrm{}}$, $B(B^0\to K^{+}{\pi }^{-})=\left({1.93}_{-0.32-0.06\mathrm{}}^{+0.34+0.15\mathrm{}}\right)\times {10}^{-5\mathrm{}}$, $B(B^{+}\to K^{+}{\pi }^0)=\left({1.63}_{-0.33-0.18\mathrm{}}^{+0.35+0.16\mathrm{}}\right)\times {10}^{-5\mathrm{}}$, $B(B^{+}\to K^0{\pi }^{+})=\left({1.37}_{-0.48-0.18\mathrm{}}^{+0.57+0.19\mathrm{}}\right)\times {10}^{-5\mathrm{}}$, and $B(B^0\to K^0{\pi }^0)=\left({1.60}_{-0.59-0.27\mathrm{}}^{+0.72+0.25\mathrm{}}\right)\times {10}^{-5\mathrm{}}$. We also set upper limits on the branching fractions for $B^{+}\to {\pi }^{+}{\pi }^0$, $B^0\to K^{+}{K}^{-}$, and $B^{+}\to K^{+}{\overline{K}}^0$.

• Received 17 April 2001

DOI:https://doi.org/10.1103/PhysRevLett.87.101801