English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Effects of charge symmetry breaking associated with the $u$ and $d$ quarkmass difference in the elastic form factors of the pion and kaon are presented.We use a confining version of the Nambu--Jona-Lasinio model. The pion and kaonare described as a dressed quark and antiquark bound states governed by theBethe-Salpeter equation, and exhibit the properties of Goldstone bosons, withthe pion mass difference given by $m_{\pi^{+}}^2 - m_{\pi^{0}}^2 \propto (m_u-m_d)^2$ as demanded by dynamical chiral symmetry breaking. We foundsignificant charge symmetry breaking effects for realistic current quark massratios ($m_u/m_d \sim 0.5$) in the quark electromagnetic form factors of thepion and kaon. We also report the effects of charge symmetry breaking on theparton distribution functions, which are rather smaller than those found in theelectromagnetic form factors.

Effects of charge symmetry breaking on form factors of the pion and kaon