Double parton distributions of the proton from basis light-front quantization

TL;DR

This paper uses basis light-front quantization to compute unpolarized and polarized double parton distributions of quarks in the proton, revealing correlations and challenging common factorization assumptions.

Contribution

It introduces a systematic calculation of DPDs using light-front wave functions derived from a Hamiltonian with confinement and one-gluon exchange, providing new insights into quark correlations.

Findings

Significant correlations between quark longitudinal momenta and transverse separation.

Calculations do not support simple $x-\vec{k}_\perp$ factorization of DPDs.

Results align qualitatively with other phenomenological models.

Abstract

Within the basis light-front quantization framework, we systematically investigate the unpolarized and longitudinally polarized double parton distributions (DPDs) of quarks inside the proton. We utilize the light-front wave functions of the proton derived in the valence sector from a Hamiltonian quantized on the light-front. The interaction terms of the Hamiltonian consist of a one-gluon exchange interaction at fixed coupling and a three-dimensional confinement potential. Our current analysis yields significant correlations of the quarks' longitudinal momenta with their transverse separation. We also demonstrate that our calculations do not support the commonly used $x-\vec{k}_\perp$ factorization of the DPDs in $x$ and $k_\perp$. Our results are qualitatively consistent with those of other phenomenological models.