ar X iv : 0 80 7 . 30 80 v 1 [ he p -

The decay B → Kπ, dominated by a b → s penguin amplitude, holds the potential for exhibiting new physics in this amplitude. In the pure QCD penguin limit one expects CKπ = 0 and SKπ = sin 2β for the coefficients of cos∆mt and sin∆mt in the time-dependent CP asymmetry. Small nonpenguin contributions lead to corrections to these expressions which are calculated in terms of isospin-related B → Kπ rates and asymmetries, using information about strong phases from experiment. We study the prospects for incisive tests of the Standard Model through examination of these corrections, and comment on a recent discussion favoring SKπ ≈ 1.