Study of charmless hadronic B decays into the final states $K\pi, \pi\pi$, and KK, with the first observation of $B \to \pi^+ \pi^$ and $B\to K^0\pi^0$
Abstract
We have studied charmless hadronic decays of B mesons into twobody final states with kaons and pions. We present preliminary results based on 9.66 million $B\bar{B}$ pairs collected with the CLEO detector. We have made the first observation of the decay $B \to \pi^+\pi^$, with the branching fraction of $Br(B \to \pi^+ \pi^) = (4.7^{+1.8}_{1.5} \pm 0.6) \times 10^{6}$. We have also observed for the first time the decay $B \to K^0\pi^0$ with the branching fraction of $Br(B \to K^0 \pi^0) = (14.8^{+5.9+2.4}_{5.13.3}) \times 10^{6}$, thus completing the set of four $K\pi$ branching fraction measurements. We present improved measurements for the decays $B\to K^{\pm}\pi^{\mp}$, $B^{\pm}\to K^0\pi^{\pm}$, and $B^{\pm}\to K^{\pm}\pi^0$. We use these and other charmless hadronic B decays to make a first determination of the value of the weak phase ${\rm Arg}(V^*_{ub})=\gamma = {113^\circ}^{+25^\circ}_{23^\circ}$.
 Publication:

arXiv eprints
 Pub Date:
 August 1999
 arXiv:
 arXiv:hepex/9908039
 Bibcode:
 1999hep.ex....8039C
 Keywords:

 High Energy Physics  Experiment
 EPrint:
 Leppho99 conference submission. All results are preliminary