Improved Method for CKM Constraints in Charmless Three-body B and Bs Decays

Recently Ciuchini, Pierini and Silvestrini proposed a method for constraining CKM parameters in B → Kππ and Bs → Kππ through phase measurements of amplitudes involving I = 3/2 K*π final states. We show that complementary information on CKM parameters may be obtained by studying the phases of ΔI = 1 B → (K*π)I=1/2, Bs → (K*(bar K))I=1 and Bs → ((bar K)*K)I=1 amplitudes. Hadronic uncertainties in these constraints from electroweak penguin operators O9 and O10, studied using flavor SU(3), are shown to be very small in B → Kππ and Bs → Kππ and somewhat larger in Bs → K(bar K)π. The first processes imply a precise linear relation between (bar ρ) and (bar η), with a measurable slope and an intercept at (bar η) = 0 involving a theoretical error of 0.03. The decays Bs → Kππ permit a measurement of involving a theoretical error below a degree. We note that while time-dependence is required when studying B0 decays at the Υ(4S), it is not needed when studying Bs decays at hadronic colliders