Self-consistent coupled-channel approach to $D$ and $\bar D$ in hot dense matter

Abstract

A self-consistent coupled-channel approach is used to study the properties of $D$ and $\bar D$ mesons in hot dense matter. The starting point is a broken SU(4) s-wave Tomozawa-Weinberg $DN$ ($\bar DN$) interaction supplemented by an attractive isoscalar-scalar term. The Pauli blocking effects, baryon mean-field bindings, and $\pi$ and open-charm meson self-energies are incorporated in dense matter at finite temperature. In the $DN$ sector, the dynamically generated $\tilde\Lambda_c$ and $\tilde\Sigma_c$ resonances remain close to their free space position while acquiring a remarkable width because of the thermal smearing of Pauli blocking. Therefore, the $D$ meson spectral density shows a single pronounced quasiparticle peak close to the free mass, that broadens with increasing density, and a low energy tail associated to smeared $\tilde\Lambda_c N^{-1}$, $\tilde\Sigma_c N^{-1}$ configurations. In the $\bar DN$ case, the low-density approximation to the repulsive $\bar D$ self-energy is found unreliable already at subsaturation densities. From this study we speculate the possible existence of $D$-mesic nuclei. We also discuss the consequences for $J/\Psi$ suppression at FAIR.