The Color Evaporation Model in Diffractive $J/\psi$ Photoproduction

TL;DR

This paper investigates the applicability of the Color Evaporation Model to describe elastic photoproduction of $J/$ and open charm, demonstrating it can do so without relying on a Pomeron.

Contribution

It shows that the Color Evaporation Model can effectively describe elastic $J/$ and open charm photoproduction without Pomeron exchange, expanding its applicability.

Findings

CEM describes elastic $J/$ photoproduction successfully.

CEM can model open charm production elastically.

The model's applicability range is analyzed.

Abstract

Our goal is the study of color effects on the $J/\psi$ and $D$ mesons production, as well as the study of their elastic production. We use the Color Evaporation Model (CEM), where a single factor takes into account the probability that the $c\bar{c}$ produced in a color octet state turns into a physical (colorless) quarkonium or continues as a color octet, producing open charm. The main result of this work, besides investigating the range of applicability of the CEM, is to show that this model can be used to describe the elastic processes of $J/\psi$ and open charm photoproduction without the use of a Pomeron.