Tomography of Pions and Kaons in the QCD Vacuum: Transverse Momentum Dependent Parton Distribution Functions

TL;DR

This paper computes the transverse momentum dependent parton distribution functions for pions and kaons within the instanton liquid model, incorporating evolution and comparing results to experimental data, advancing understanding of QCD vacuum structure.

Contribution

It introduces a novel calculation of pion and kaon TMDPDFs using the ILM, including evolution with the Collins-Soper kernel and comparison to Drell-Yan data.

Findings

TMDPDFs are successfully modeled within the ILM framework.

Results are evolved to match experimental conditions.

Comparison shows consistency with existing Drell-Yan extractions.

Abstract

We evaluate the pion and kaon transverse momentum dependent parton distribution functions (TMDPDFs) in the instanton liquid model (ILM), a model of the QCD vacuum at low resolution. The relevant TMDs are factored into a constituent quark distribution times a rapidity dependent soft factor from staple-shaped Wilson lines, for fixed parton longitudinal momentum and transverse separation. The results are evolved to higher rapidities using the Collins-Soper (CS) kernel and higher resolution using renormalization group evolution. The comparison to existing extractions of pion TMDs from Drell-Yan (DY) data is briefly discussed.