Quarkonium Production in an Improved Color Evaporation Model

TL;DR

This paper introduces an improved color evaporation model for heavy quarkonium production, incorporating invariant mass constraints and momentum shifts, resulting in better agreement with experimental charmonium yields and ratios.

Contribution

The paper presents a novel version of the color evaporation model with specific constraints and modifications that enhance its predictive accuracy for quarkonium production.

Findings

Better description of charmonium yields

Improved ratio of $$ over $J/$

Enhanced agreement with experimental data

Abstract

We propose an improved version of the color evaporation model to describe heavy quarkonium production. In contrast to the traditional color evaporation model, we impose the constraint that the invariant mass of the intermediate heavy quark-antiquark pair to be larger than the mass of produced quarkonium. We also introduce a momentum shift between heavy quark-antiquark pair and the quarkonium. Numerical calculations show that our model can describe the charmonium yields as well as ratio of $\psi^\prime$ over $J/\psi$ better than the traditional color evaporation model.