Patricia Magalhaes (Bristol)

Challenges and future of 3-body heavy meson decays

Abstract: Three-body decays of heavy-flavoured hadrons into light particles are a natural source of information about two-body scattering amplitudes, as an alternative to the early scattering data. However, the determination of the two-body amplitudes requires the understanding of the role of final-state interactions (FSI) and strong phases from the primary weak vertex. This is also a crucial step to understand the massive localized CP violation observed in B⁺ → h₁^-h₂⁺h₃⁺ (h_i ≡ π, K) decays from LHCb. The gigantic samples of B and D decays collected by the LHCb, BES-III and, in the near future, Belle II experiments motivated theoretical efforts in the past decade towards building models that are based on more solid grounds. These models improve essentially the description of FSI by using coupled-channels formalism and imposing two-body unitarity. In this talk an overview of these models will be presented. In particular, two important results will be discussed, namely D⁺ → K^-K⁺K⁺ and B⁺ → K^-K⁺K⁺. In the first case, the focus is on the determination of the K^-K⁺ scattering amplitudes, whilst in the second decay, the focus is on the underlying mechanisms of the CP asymmetries pattern observed in the Dalitz plot.