Measurement of Branching Fractions for B → ππ , Kπ , and KK Decays

We report measurements of the branching fractions for B0→π+π- , K+π- , K+K- , and K0π0 and B+→π+π0 , K+π0 , K0π+ , and K+ bar K0 , based on 10.4 fb-1 of data collected on the Υ(4S) resonance with the Belle detector. We find B(B0→π+π-)=(0.56+0.23+0.04-0.20-0.0 5) x 10-5 , B(B0→K+π-)=(1.93+0.34 +0.15-0.32-0.06) x 10-5 , B(B+→K+π0)=(1.63+0.35+0.16-0.33-0.1 8) x 10-5 , B(B+→K0π+)=(1.37+0.57+0.19-0.48-0.1 8) x 10-5 , and B(B0→K0π0)=(1.60+0.72+0.25-0.59-0.2 7) x 10-5 . We also set upper limits on the branching fractions for B+→π+π0 , B0→K+K- , and B+→K+bar K0