Annihilation contribution and B→a0π,f0K decays

We analyze the B0→a±0 π-+ and B-,0 →f0K-,0 decays and show that a consistent phenomenological picture can be obtained within the factorization approximation. In this approach the O6 operator provides the dominant contributions to the suppressed channel B0→a+0π-. An estimate of the annihilation form factor using perturbative QCD indicates that this contribution is not negligible, moreover interference with other penguin contributions includes a free parameter since the phase of the annihilation amplitude is not determined. Assumptions based on SU(2) isospin symmetry provide relations between different B decays involving one scalar and one pseudoscalar meson. (orig.)