A critical look at hadronic b → s penguin modes

Within the Standard Model, the time-dependent CP asymmetry S(t) in hadronic b → s penguin decay modes, such as B → (φ, f₀, η, η, η′, ρ⁰, π⁰, ω)K_S, probes sin(2β) up to small corrections. Any significant deviation from the Standard Model prediction would be a clear hint for new physics. In this context, we consider the branching ratios and CP asymmetries in two theoretically clean modes, namely in B → f₀(980)K_S and B → φK_S decays, to the end of determining the deviation of S(t) from sin(2β) arising from Standard Model physics. We use the QCD factorization framework for the decay amplitudes and employ a parameter scan to probe a broad range of theoretical models, exploring variations in the inputs at the 3σ level and the ill-known O(1/M_B) corrections with 100% uncertainty. If we demand that the theoretical model confronts the empirical branching ratios successfully, the excursions in S(t) from sin(2β) are under sufficient theoretical control to enable the interpretation of experimental results of much higher precision.