Properties of $Z_c(3900)$ tetraquark in a cold nuclear matter

Abstract

The study of medium effects on properties of particles embedded in nuclear matter is of great importance for understanding the nature and internal quark-gluon organization as well as exact determination of the quantum numbers, especially of the exotic states. In this context, we study the physical properties of one of the famous charmonium-like states, $Z_c(3900)$, in a cold dense matter. We investigate the possible shifts in the mass and current-meson coupling of the $Z_c(3900)$ state due to the dense medium at saturation density, ${\rho }^{sat}$, by means of the in-medium sum rules. We also estimate the vector self-energy of this state at saturation nuclear matter density. We discuss the behavior of the spectroscopic parameters of this state with respect to the density up to a high density corresponding to the core of neutron stars, $\rho \approx 5{\rho }^{sat}$. Both the mass and current-coupling of this state show nonlinear behavior and decrease with respect to the density of the medium: the mass reaches roughly $30\%$ of its vacuum value at $\rho =5{\rho }^{sat}$, while the current-coupling approaches zero at $\rho \approx 2.1{\rho }^{sat}$, when the central values of the auxiliary and other input parameters are used.

Comments: 13 Pages, 7 Figures and 2 Tables. Some typos were corrected