We investigate how a dense nuclear medium affects the  D_s (2317)^±  and  T_cc (3875)^±  states. In vacuum, these states are modeled as isoscalar DK  (D ̅K ̅) and  DD*  (D ̅D ̅^*) S-wave bound states, formed through effective interactions that correspond to different Weinberg compositeness models. Matter effects are introduced via two-meson loop functions, incorporating the self-energies acquired by D^((*)),  D ̅^((*)),  K, and K ̅ mesons when they interact in a nuclear medium. Although D_s (2317) and T_cc (3875)  have identical particle-antiparticle lineshapes in vacuum, they display highly distinct density patterns in nuclear matter. This charge-conjugation asymmetry mainly arises from the differing interactions of kaons (D ̅ and D ̅^*) and antikaons (D and D*) with the nucleons in the dense medium. Our findings demonstrate that the in-medium lineshapes of these resonances are closely tied to their molecular DK and DD* components, offering a new approach to determine/constrain the internal structure of these exotic states.

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郭奉坤 研究员