Double parton distributions in Light-Front constituent quark models

TL;DR

This paper investigates double parton distribution functions within a relativistic light-front constituent quark model, revealing correlations and symmetries relevant for understanding the 3D structure of protons in high-energy collisions.

Contribution

It introduces a covariant light-front approach to study dPDFs, overcoming previous limitations and analyzing the role of spin and transverse momentum correlations.

Findings

Relativistic light-front scheme improves support of dPDFs.

Transverse momentum correlations are generated by boost treatments.

Spin correlations significantly affect dPDF features.

Abstract

Double parton distribution functions (dPDF), accessible in high energy proton-proton and proton nucleus collisions, encode information on how partons inside a proton are correlated among each other and could represent a tool to explore the 3D proton structure. In recent papers, double parton correlations have been studied in the valence quark region, by means of constituent quark models. This framework allows to understand clearly the dynamical origin of the correlations and to establish which, among the features of the results, are model independent. Recent relevant results, obtained in a relativistic light-front scheme, able to overcome some drawbacks of previous calculations, such as the poor support, will be presented. Peculiar transverse momentum correlations, generated by the correct treatment of the boosts, are obtained. The role of spin correlations will be also shown. In this covariant approach, the symmetries of the dPDFs are unambiguously reproduced. The study of the QCD evolution of the model results has been performed in the valence sector, showing that, in some cases, the effect of evolution does not cancel that of correlations.