Unified study of Bₛ⁰ → X(3872) π ⁺π ⁻ (K⁺ K⁻) and Bₛ⁰ → ψ (2S) π ⁺π ⁻ (K⁺ K⁻) processes

We perform a unified description of the experimental data of the π ⁺π ⁻ π + π - invariant mass spectra of Bₛ⁰ → ψ (2S) π ⁺π ⁻ B s 0 → ψ ( 2 S ) π + π - , the π ⁺π ⁻ π + π - and K⁺ K⁻ K + K - invariant mass spectra of Bₛ⁰ → X(3872) π ⁺π ⁻ (K⁺ K⁻) B s 0 → X ( 3872 ) π + π - ( K + K - ) , and the ratio of branch fractions B[Bₛ⁰ → X(3872)(K⁺K⁻)non-φ]/ B[Bₛ⁰ → X(3872)π ⁺ π ⁻] B [ B s 0 → X ( 3872 ) ( K + K - ) non - ϕ ] / B [ B s 0 → X ( 3872 ) π + π - ] . The strong final state interactions between the two pseudoscalars are taken into account using a parametrization fulfilling unitarity and analyticity. We find that there is universality in the coupling constants for <jats:tex-math