Production of $\psi (4040)$, $\psi (4160)$, and $\psi (4415)$ mesons in hadronic matter

TL;DR

This study investigates the production of specific charmonium states in hadronic matter through quark interchange, providing cross sections and rate equations, and predicts their relative abundances at the kinetic freeze-out in high-energy heavy-ion collisions.

Contribution

It introduces the first calculation of production cross sections for $\\psi$ mesons in hadronic matter and develops master rate equations to predict their yields in Pb-Pb collisions.

Findings

Peak cross sections for $\\psi(4040)$ are comparable or larger than those for $\\psi(4415)$.

The $\\psi(4040)$ has a higher number density at freeze-out than $\\psi(4415)$ and $\\psi(4160)$.

The order of meson abundances at freeze-out is $\\psi(4040)$ > $\\psi(4415)$ > $\\psi(4160)$.

Abstract

We present the first study of production of $\psi (4040)$, $\psi (4160)$, and $\psi (4415)$ mesons in hadronic matter. Quark interchange between two colliding charmed mesons leads to the production of the three mesons. We calculate unpolarized cross sections for the reactions, $D\bar{D} \to \rho R$, $D\bar{D}^* \to \pi R$, $D\bar{D}^* \to \rho R$, $D^*\bar{D} \to \pi R$, $D^*\bar{D} \to \rho R$, $D^*\bar{D}^* \to \pi R$, and $D^*\bar{D}^* \to \rho R$, where $R$ stands for $\psi (4040)$, $\psi (4160)$, and $\psi (4415)$. In the temperature region covering hadronic matter the peak cross sections of producing $\psi (4040)$ are similar to or larger than the ones of producing $\psi (4415)$, and the latter are generally larger than those of producing $\psi (4160)$. With the cross sections we establish new master rate equations for $\psi (4040)$, $\psi (4160)$, and $\psi (4415)$. The equations are solved for central Pb-Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV at the Large Hadron Collider. Solutions of the equations show that the $\psi (4040)$ number density at kinetic freeze-out of hadronic matter is larger than the $\psi (4415)$ number density which is larger than the $\psi (4160)$ number density.