The production of the $$X(3872)$$ X ( 3872 )  particle in heavy-ion collisions has been contemplated as an alternative probe of its internal structure. To investigate this conjecture, we perform transport calculations of the $$X(3872)$$ X ( 3872 )  through the fireball formed in nuclear collisions at the LHC. Within a kinetic-rate equation approach as previously used for charmonia, the formation and dissociation of the $$X(3872)$$ X ( 3872 )  is controlled by two transport parameters, i.e., its inelastic reaction rate and thermal-equilibrium limit in the evolving hot QCD medium. While the equilibrium limit is controlled by the charm production cross section in primordial nucleon-nucleon collisions (together with the spectra of charm states in the medium), the structure information is encoded in the reaction rate. We study how different scenarios for the rate affect the centrality dependence and transverse-momentum ($$p_T$$ p T ) spectra of the $$X(3872)$$ X ( 3872 ) . Larger reaction rates associated with the loosely bound molecule structure imply that it is formed later in the fireball evolution than the tetraquark and thus its final yields are generally smaller by around a factor of two, which is qualitatively different from most coalescence model calculations to date. The $$p_T$$ p T  spectra provide further information as the later decoupling time within the molecular scenario leads to harder spectra caused by the blue-shift from the expanding fireball.

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The production yields of the X(3872) particle in heavy-ion collisions have been suggested to be sensitive to its internal structure. While the thermal equilibrium limit of the X(3872)abundance only depends on its mass, its inelastic reaction rates in a hot medium are expected to be different depending on whether it is a loosely bound hadronic molecule or a compact tetraquark dominated by colored diquark-antidiquark configurations. Here we implement these scenarios into a kinetic rate equation as previously used in applications to charmonium and bottomonium observables. While the equilibrium limit, controlled by the charm-quark content in the fireball, is universal for both scenarios (and decreases with temperature), the molecular scenario is characterized by a much larger width in the hadronic medium than for the tetraquark. Consequently, the average production time of the molecular X(3872)is significantly later than for the tetraquark, leading to to a factor of ∼2 smaller production of the former compared to the latter. This outcome is qualitatively different from most coalescence model calculations to date. In addition, we calculate pertinent transverse-momentum spectra, which turn out to be harder for the molecular scenario due to the larger blue-shift caused by the collective flow in the fireball at later times.