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

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.

Comments: 23 pages, 13 figures, typo fixed and plots corrected