Towards new frontiers in the exploration of charmless non-leptonic B decays

Non-leptonic B decays into charmless final states offer an important laboratory to study CP violation and the dynamics of strong interactions. Particularly interesting are B_s⁰ → K⁻K⁺ and B_d⁰ → π⁻π⁺ decays, which are related by the U-spin symmetry of strong interactions, and allow for the extraction of CP-violating phases and tests of the Standard Model. The theoretical precision is limited by U-spin-breaking corrections and innovative methods are needed in view of the impressive future experimental precision expected in the era of Belle II and the LHCb upgrade. We have recently proposed a novel method to determine the Bs0−B¯s0 mixing phase ϕ_s from the B_s⁰ → K⁻K⁺, B_d⁰ → π⁻π⁺ system, where semileptonic B_s⁰ → K⁻ℓ⁺ν_ℓ, B_d⁰ → π⁻ℓ⁺ν_ℓ decays are a new ingredient and the theoretical situation is very favourable. We discuss this strategy in detail, with a focus on penguin contributions as well as exchange and penguin-annihilation topologies which can be probed by a variety of non-leptonic B decays into charmless final states. We show that a theoretical precision as high as O(0.5 °) for ϕ_s can be attained in the future, thereby offering unprecedented prospects for the search for new sources of CP violation.