Improved Measurements of Branching Fractions for B->Kpi, pipi and KK Decays

Abstract

We report improved measurements of branching fractions for $B\to Kπ$, $π^+π^-$, $π^+π^0$ and $K\bar{K}$ decays based on a data sample of 85.0 million $B\bar{B}$ pairs collected at the $Υ(4S)$ resonance with the Belle detector at the KEKB $e^+e^-$ storage ring. This data sample is almost three times larger than the sample previously used. We observe clear signals for $B\to Kπ$, $π^+π^-$ and $π^+π^0$ decays and set upper limits on $B\to K\bar{K}$ decays. The results can be used to give model-dependent constraints on the CKM angle $ϕ_3$, as well as limits on the hadronic uncertainty in the time-dependent analysis of the angle $ϕ_2$.