Penguin Effects in B⁰_d→ J/φK⁰_Sand B⁰_s→ J/Φφ

Controlling the contributions from doubly Cabibbo-suppressed penguin topologies in the decays B⁰_d→ J/φK⁰_Sand B⁰_s→ J/Φφ is mandatory to reach the highest possible precision in the measurement of the B⁰_q-B⁰_q(q = d, s) mixing phases Φd and φs. The penguin contributions can be determined using a strategy based on the SU(3) flavour symmetry of QCD. Using the latest experimental data, we update our combined analysis of the decays B⁰_d→ J/φK⁰_S, B⁰_s→ J/Φφ and their control channels B⁰_d→ J/φK⁰_S, B⁰_d→ J/φπ⁰and B⁰_d→ J/φρ⁰. This allows us to simultaneously determine the penguin parameters and both mixing phases. We discuss how the branching fractions of these decays can be used to probe the size of non-factorisable SU(3)- breaking effects, which form the main theoretical uncertainty associated with our SU(3)-based strategy, and provide new insights into the factorisation approach.