Precision Tests of Flavor and CP violation in B Decays

Abstract

Isospin and flavor SU(3) set stringent bounds on penguin pollution in $B^0(t)\to ρ^+ρ^-$, providing a theoretically precise determination of $α\equiv ϕ_2 $, $α= (91\pm 7_{\rm exp}\pm 3_{\rm th})^\circ$. Isospin breaking in a sum rule for $B\to Kπ$ rates is shown to be suppressed. A similar sum rule holds for CP asymmetries in $B\to Kπ$. Violation of these sum rules would be evidence for an anomalous $ΔI=1$ piece in ${\cal H}_{\rm eff}$.