Probing nonperturbative transverse momentum dependent PDFs with chiral perturbation theory: the $\bar{d}-\bar{u}$ asymmetry

TL;DR

This paper employs chiral perturbation theory to analyze the nonperturbative aspects of transverse momentum dependent PDFs, specifically predicting a natural exponential suppression and the $ar{d}-ar{u}$ asymmetry in the proton.

Contribution

It introduces a novel application of chiral perturbation theory to TMD PDFs, providing predictions for the $ar{d}-ar{u}$ asymmetry and long-distance behavior.

Findings

Predicts exponential suppression of TMD PDFs at long distances.

Provides a theoretical estimate of the $ar{d}-ar{u}$ asymmetry.

Explores effects of additional nonperturbative physics on TMD PDFs.

Abstract

We use chiral perturbation theory to study the long distance regime of transverse momentum dependent parton distribution functions (TMD PDFs). Chiral corrections to the TMD PDFs are computed from proton to pion/baryon splittings. For consistent power counting, we find that the fraction of the proton's momentum that a pion may carry must be kept small. We make predictions for a $\bar{d}-\bar{u}$ asymmetry in the proton's TMD PDFs and find that the effective theory gives a natural exponential suppression of the TMD PDF at long distances. We then explore the effects that additional nonperturbative physics may have on the TMD $\bar{d}-\bar{u}$ asymmetry.