The T₂ₒ state observed in the decay Dₒ₁ (2460) ^+ Dₛ^+π^+π^- provides direct evidence for an isovector open-charm tetraquark state with strangeness. We develop a unified theoretical framework that consistently incorporates triangle loops and DK-Dₛπ rescattering. Especially, DK-Dₛπ coupled-channel interactions through off-diagonal potential terms provide a novel perspective on the origin of the T₂ₒ pole. Based on the systematic description of the Dₒ₁ mass spectrum, the two-peak structure in Dₒ₁ (2460) decay is perfectly reproduced, and explained by the interference of the f₀ resonance and rescattering diagrams. In contrast, only one-peak structure is predicted in Dₒ₁ (2536) decay, since it is dominated by rescattering only. This difference originates from the S- and D-wave dominance for Dₒ₁ (2460) and Dₒ₁ (2536) coupling with D^*K channel, respectively, which reflects the internal structures of the two Dₒ₁ states. This unified approach demonstrates how decay and production mechanisms encode different aspects of dynamics, offering an opportunity to disentangle the nature of exotic hadrons.
Yang et al. (Thu,) studied this question.