Charm-meson molecules production in a warm hadron gas*

The $X(3872)$ has recently been observed in heavy-ion collisions by the CMS collaboration. Understanding the production rate of $X$ in heavy-ion collision could help resolve its nature. The number of $X$ produced by hadronization of the quark-gluon plasma is modified by hadronic interactions in the expanding hadron gas. We calculate the formation and break-up rates using XEFT for $X$ in a warm pion gas. These rates are used to evolve the number of $X$ from hadronization to past kinetic freeze-out.