From C to Parton Sea: Bjorken-x Dependence of the PDFs

TL;DR

This paper presents the first direct calculation of the Bjorken-x dependence of parton distribution functions using LaMET, advancing our understanding of nucleon structure and aiding high-energy physics experiments.

Contribution

The study introduces a novel lattice QCD approach to directly compute the x-dependent PDFs, overcoming previous limitations to moments and enabling detailed nucleon structure analysis.

Findings

First direct calculation of x-dependent PDFs from lattice QCD

Exploratory analysis of antiquark/sea flavor asymmetry

Potential to extend to gluon and transverse-momentum distributions

Abstract

Studying the structure of nucleons is not only important to understanding the strong interactions of quarks and gluons, but also to improving the precision of new-physics searches. Since a broad class of experiments, including the LHC and dark-matter detection, require Standard-Model backgrounds with parton distribution functions (PDFs) as inputs for disentangling SM contributions from potential new physics. For a long time, lattice calculations of the PDFs (as well as many hadron structures) has been limited to the first few moments. In this talk, we present a first direct calculation of the Bjorken-x dependence of the PDFs using Large-Momentum Effective Theory (LaMET). An exploratory study of the antiquark/sea flavor asymmetry of these distributions will be discussed. This breakthrough opens an exciting new frontier calculating more complicated quantities, such as gluon structure and transverse-momentum dependence, which will complement existing theoretical programs for the upcoming Electron-Ion Collider (EIC) or Large Hadron-Electron Collider (LHeC).