Resolving the ϕ 2 (α) ambiguity in B 0 → a 1 ± π ∓ $$ {\ rm{a}}_1^{\pm }{\uppi}^{\mp }

Abstract I propose an alternative method for measuring the CP violating phase ϕ 2(α) without ambiguity in an extended SU (3) flavour symmetry analysis, which can ultimately be achieved by exploiting interference effects between B → AP and B → VV decay channels, where A, V, P indicates an axial-vector, vector and pseudo-scalar meson, respectively. Under certain assumptions on the relevant decays based on current experimental results and minimal theoretical input, I demonstrate with an idealised amplitude model that a programme to extract a single solution for ϕ 2 in the range [0, π], with the added possibility to simultaneously constrain non-factorisable SU(3)-breaking effects, could be executed to similar precision using Run 3 data at LHCb and the final Belle II sample.