Penguins in B decays

Abstract

We report on recent progress in studying two aspects of $B$ physics, in which penguin amplitudes play an important role: (1) Bounds on penguin pollution in $B^0(t) \to π^+π^-$ constraining CKM parameters, and a lower bound on $B^0 \to π^0π^0$ improving precision in $\sin 2α$. (2) A suggestion for measuring the photon polarization in electroweak penguin decay, $B \to K_1(1400)γ$, providing a precision test of the Standard Model and a probe for new physics.