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 $B^0(t)\to {\pi }^{+}{\pi }^{-}$ constraining CKM parameters, and a lower bound on $B^0\to {\pi }^0{\pi }^0$ improving precision in $\sin 2\alpha$. (2) A suggestion for measuring the photon polarization in electroweak penguin decay, $B\to K_1(1400)\gamma$, providing a precision test of the Standard Model and a probe for new physics.

Comments: 12 pages, invited talk at the Ninth International Symposium on Heavy Flavor Physics, Caltech, Pasadena, CA, Sept. 2001