Unified study of Bₛ⁰ X (3872) ^+ ^- (K^+ K^-) and Bₛ⁰ (2S) ^+ ^- (K^+ K^-) processes

Abstract We perform a unified description of the experimental data of the ^+ ^- π + π - invariant mass spectra of Bₛ⁰ (2S) ^+ ^- B s 0 → ψ (2 S) π + π -, the ^+ ^- π + π - and K^+ K^- K + K - invariant mass spectra of Bₛ⁰ X (3872) ^+ ^- (K^+ K^-) B s 0 → X (3872) π + π - (K + K -), and the ratio of branch fractions BBₛ⁰ X (3872) (K^+K^-) ₍₎₍- / BBₛ⁰ X (3872) ^+ ^- 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