Meson cloud effects on kaon quark distribution functions and the SU(3) flavor symmetry

TL;DR

This paper investigates how meson cloud effects influence the valence quark distributions in the kaon, revealing a smaller SU(3) flavor symmetry breaking than previously thought, using a chiral constituent quark model and QCD evolution.

Contribution

It introduces a detailed analysis of meson cloud effects on kaon quark distributions within the chiral constituent quark model, highlighting a reduced SU(3) flavor symmetry breaking.

Findings

Meson cloud effects significantly modify bare quark distributions.

The observed SU(3) flavor symmetry breaking is smaller than in previous models.

The model successfully reproduces experimental valence quark distribution ratios.

Abstract

We present our analysis on the valence quark distribution functions of the $K^{+}$ meson, $v^{K (u)} (x, Q^2)$ and $v^{K (\bar{s})} (x, Q^2)$, taking into account the meson cloud effects in the framework of the chiral constituent quark model. Assuming appropriate bare quark distribution functions at the initial scale, evaluating the Goldstone boson dressing corrections with the model, and performing the QCD evolution, one can obtain the realistic dressed distributions at a certain scale. The phenomenologically satisfactory valence quark distribution of the pion was obtained in the previous study and there are available experimental data of the valence $u$ quark distribution ratio $v^{K(u)} (x, Q^2) / v^{\pi (u)} (x, Q^2)$, which enable us to obtain the kaon quark distribution functions. Besides presenting the resulting dressed distributions, we also show how the meson cloud effects affect the bare distributions in detail. A striking result is that the observed size of the SU(3) flavor symmetry breaking is considerably smaller than those seen in the preceding works based on other approaches.