Charm mesons at FAIR

TL;DR

This paper investigates how charm mesons behave in hot, dense matter using a coupled-channel approach, revealing broadening spectral functions and implications for $J/ ext{Psi}$ suppression at FAIR.

Contribution

It provides a self-consistent model of charm mesons in medium, including medium effects and resonance behavior, with implications for heavy-ion collision experiments.

Findings

$D$ meson spectral function broadens with density.

Resonances $ ilde\Lambda_c$ and $ ilde\\Sigma_c$ remain near free space but gain large widths.

Low-density approximation for $ar D N$ interactions is unreliable at subsaturation densities.

Abstract

The in-medium properties of charm mesons ($D$ and $\bar D$) in a hot and dense matter are studied. A self-consistent coupled-channel approach is driven by a broken SU(4) s-wave Tomozawa-Weinberg interaction supplemented by an attractive isoscalar-scalar term. As medium effects, we include Pauli blocking, baryon mean-field bindings, and $\pi$ and open-charm meson self-energies. The dynamically generated $\tilde\Lambda_c$ and $\tilde\Sigma_c$ resonances in the $DN$ sector remain close to their free space position but acquire large widths. The resultant $D$ meson spectral function, which shows a single pronounced quasiparticle peak close to the free mass that broadens with increasing density, also has a long low energy tail associated with smeared $\tilde\Lambda_c N^{-1}$, $\tilde\Sigma_c N^{-1}$ configurations. The low-density approximation for the $\bar D N$ is questionable already at subsaturation densities. We touch upon the implication of our study for $J/\Psi$ suppression at FAIR.