X (3872) and Tcc: Structures and productions in heavy ion collisions

We argue why the recently observed Tcc could either be a compact multiquark configuration or a loosely bound molecular configuration composed of charmed mesons, whereas the X (3872) is most likely a molecular configuration. The argument is based on different short range interactions for these tetraquark states coming from the color-color and color-spin interaction in a quark model, and the presence of a common strong D-wave mixing at larger distance similar to the deuteron case, which for the molecular configurations leads to large sizes. Such an analogy at large distance allows us to calculate the transverse momentum dependence of the loosely bound molecular configuration of tetraquarks produced in heavy ion collisions using the coalescence model that successfully reproduces the deuteron data using the proton spectra. The ratio of the integrated X (3872) yield obtained from our method to the psi (2S) yield obtained from the statistical hadronization model method is calculated to be 0.806 +/- 0.234, which is a factor of 2.47 larger than that obtained by using statistical model predictions for both particles and in line with the data from the CMS experiment. As the previously calculated transverse momentum distribution of the Tcc assuming the structure to be a compact multiquark configuration is markedly different, experimental measurements of the transverse distribution of the tetraquark states will discriminate between their two possible structures.

Automated summary

We discuss the possible structures of the observed Tcc and X(3872) states, arguing that Tcc could be a compact multiquark configuration while X(3872) is more likely a molecular configuration. We base our argument on the different short range interactions and the presence of a common strong mixing at larger distances. Using the coalescence model, we calculate the transverse momentum dependence of the tetraquarks produced in heavy ion collisions and compare it with experimental data. Our results suggest that the previously assumed compact multiquark structure of Tcc is significantly different from the observed distribution, providing evidence for its molecular configuration.