SCET Analysis of B -> K pi, B -> K Kbar, and B -> pi pi Decays

Abstract

B -> K pi and related decays are studied in the heavy quark limit of QCD using the soft collinear effective theory (SCET). We focus on results that follow solely from integrating out the scale mb, without expanding the amplitudes for the physics at smaller scales such as alphas(sqrt{Epi LambdaQCD}). The reduction in the number of hadronic parameters in SCET leads to multiple predictions without the need of SU(3). We find that the CP-asymmetry in $B^-\to pi^0 K^-$ should have a similar magnitude and the same sign as the well measured asymmetry in $\bar B^0 \toπ^+ K^-$. Our prediction for Br(K^+π^-) exceeds the current experimental value at the 2 sigma level. We also use our results to determine the corrections to the Lipkin and CP-asymmetry sum rules in the standard model and find them to be quite small, thus sharpening their utility as a tool to look for new physics.