$B\to \pi \pi$ decays: branching ratios and CP asymmetries

Abstract

Theoretically motivated smallness of the penguin amplitude in $B\to \pi \pi$ decays allowes to calculate the value of the unitarity triangle angle $\alpha ({\varphi }_2)$ with good accuracy. The relatively large branching ratio of the decay into ${\pi }^0{\pi }^0$ is explained by the large value of FSI phase difference between $\Delta I=1/2$ and $\Delta I=3/2$ tree amplitudes.

Comments: Analysis of direct CPV asymmetries is expanded; the relation with that in $K\pi$ decays is discussed. Submitted to Yad. Fiz