Heavy-light susceptibilities in a strongly coupled quark-gluon plasma

Quark number susceptibilities as computed in lattice QCD are commonly believed to provide insights into the microscopic structure of QCDmatter, in particular its degrees of freedom. We generalize a previously constructed partonic T -matrix approach to finite chemical potential to calculate various susceptibilities, in particular for configurations containing a heavy charm quark. At vanishing chemical potential and moderate temperatures, this approach predicts large collisional widths of partons generated by dynamically formed hadronic resonance states which lead to transport parameters characteristic for a strongly coupled system. The quark chemical potential dependence is implemented into the propagators and the in-medium color potential, where two newly introduced parameters for the thermal and screening masses are fixed through a fit to the baryon number susceptibility, chi(B)(2). With this setup, we calculate heavy-light susceptibilities without further tuning; the results qualitatively agree with the lattice-QCD (lQCD) data for both chi(uc)(11) and chi(uc)(22). This implies that the lQCD results are compatible with a significant content of broad D-meson and charm-light diquark bound states in a moderately hot quark-gluon plasma.

Automated summary

In this study, quark number susceptibilities, especially those involving heavy charm quarks, were computed using lattice QCD. The results indicate that at moderate temperatures, this approach can predict particles with large collisional widths, which characterize a strongly coupled system. Furthermore, the study found that the lattice QCD results are consistent with the existence of broad D-meson and charm-light diquark bound states in a quark-gluon plasma at moderately high temperatures.