Generalized parton distributions of sea quarks in the proton from nonlocal chiral effective theory

TL;DR

This paper computes the sea quark generalized parton distributions in the proton using a nonlocal covariant chiral effective theory, incorporating one-loop contributions and ensuring gauge invariance, to compare with phenomenology and lattice QCD.

Contribution

It introduces a nonlocal covariant chiral effective theory approach to calculate sea quark GPDs, including gauge invariance and charge conservation, providing new insights into flavor asymmetries and strange form factors.

Findings

Flavor asymmetries for sea quarks are quantified at zero and finite momentum transfer.

Strange form factors are extracted and compared with phenomenological and lattice QCD results.

The approach ensures gauge invariance through a gauge link expansion in the nonlocal Lagrangian.

Abstract

We calculate the spin-averaged generalized parton distributions (GPDs) of sea quarks in the proton at zero skewness from nonlocal covariant chiral effective theory, including one-loop contributions from intermediate states with pseudoscalar mesons and octet and decuplet baryons. A relativistic regulator is generated from the nonlocal Lagrangian where a gauge link is introduced to guarantee local gauge invariance, with additional diagrams from the expansion of the gauge link ensuring conservation of electric charge and strangeness. Flavor asymmetries for sea quarks at zero and finite momentum transfer, as well as strange form factors, are obtained from the calculated GPDs, and results compared with phenomenological extractions and lattice QCD.