A many-body system that includes loosely bound molecules can be described by an effective field theory with a relevant interaction whose strength is proportional to the small inverse scattering length of the constituents.  The “contact” for such a system is the thermodynamic variable conjugate to the large scattering length.  In the dilute limit, the number density of loosely bound molecules is proportional to the contact.  A central relativistic heavy-ion collision produces an expanding hadron gas in which charm mesons are in thermal equilibrium.  As a consequence,  the production rate of loosely bound charm-meson molecules, such as X(3872), can be determined from the contact at the time of the kinetic freezeout of charm mesons.

TUM Physics Dept., Room 3344
Room 3344 (Theory Library)
Go to map

Prof. Eric Braaten, Ohio State University, is an ORIGINS guest from 15. April - 3. May, 2024,  hosted by Prof. Nora Brambilla, TUM