Charmonium production in high multiplicity p p collisions and the structure of the proton

TL;DR

This paper explores how the spatial distribution of partons within a proton, modeled as a Y-shape, influences charmonium production in high multiplicity proton-proton collisions, explaining observed data trends.

Contribution

It introduces a model considering the Y-shaped proton structure and analyzes how quark and gluon distributions affect charmonium production in different collision centralities.

Findings

Gluon-gluon collisions dominate charm production at high multiplicity.

Proton structure affects the growth of charmonium production cross sections.

Model explains the increase in charmonium yields with collision centrality.

Abstract

In this work we study charmonium production in high multiplicity proton-proton collisions. We investigate the role of the spatial distribution of partons in the protons and assume that the proton has a Y shape. In this configuration quarks are more at the surface and gluons in the inner part of the proton. Going from peripheral to more central and then to ultra-central proton-proton collisions, we go from quark-quark collisions to gluon-gluon collisions. Since gluons are much more abundant, the cross sections grow. In the case of charm production this growth is enhanced by the fact that, $\sigma( g + g \to c + \bar{c}) >> \sigma( q + \bar{q} \to c + \bar{c})$. These effects can explain the growth seen in the data.