  In this paper we study CP violation in $B\to PP$ decays in the Standard Model
using SU(3) flavor symmetry. With SU(3) symmetry only seven hadronic parameters
are needed to describe $B\to PP$ decays in the SM when annihilation
contributions are neglected. The relevant hadronic parameters can be determined
using known experimental data from $B\to \pi\pi$ and $B\to K \pi$. We predict
branching ratios and CP asymmetries for some of the unmeasured $B \to PP$
decays. Some of the CP asymmetries can be large and measured at B factories.
The effects of annihilation contributions can also be studied using present
experimental data. Inclusion of annihilation contributions introduces six more
hadronic parameters. We find that annihilation contributions are in general
small, but can have significant effects on CP asymmetries and some $B_s \to
PP$.

High Energy Physics - Phenomenology