Parton Distribution in Pseudoscalar Mesons with a Light-Front Constituent Quark Model

TL;DR

This paper calculates the pion and kaon distribution amplitudes using a light-front constituent quark model, explicitly incorporating flavor-SU(3) symmetry breaking via quark masses, and compares different on-shell conditions for the kaon PDFs.

Contribution

It introduces a detailed calculation of meson distribution amplitudes with explicit flavor symmetry breaking in a light-front framework, comparing different on-shell conditions for the kaon.

Findings

Kaon PDFs show asymmetry due to flavor-SU(3) symmetry breaking.

Comparison of on-shell conditions reveals differences in kaon distribution functions.

Explicit inclusion of quark mass effects impacts the shape of the distribution amplitudes.

Abstract

We compute the distribution amplitudes of the pion and kaon in the light-front constituent quark model with the symmetric quark-bound state vertex function. In the calculation we explicitly include the flavor-SU(3) symmetry breaking effect in terms of the constituent quark masses of the up (down) and strange quarks. To calculate the kaon parton distribution functions~(PDFs), we use both the conditions in the light-cone wave function, i.e., when $\bar{s}$ quark is on-shell, and when $u$ quark is on-shell, and make a comparison between them. The kaon PDFs calculated in the two different conditions clearly show asymmetric behaviour due to the flavor SU(3)-symmetry breaking implemented by the quark masses.