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 Plus annual

Presents the access of premium content as premium feature

Premium Content

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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We study the $\eta \to \gamma \gamma$ and $\eta \to \pi^0 \gamma \gamma$decays using an extended three-flavor Nambu-Jona-Lasinio model that includesthe 't~Hooft instanton induced interaction. We find that the $\eta$-meson mass,the $\eta \to \gamma \gamma$ decay width and the $\eta \to \pi^0 \gamma \gamma$decay width are in good agreement with the experimental values when the$U_{A}(1)$ breaking is strong and the flavor $SU(3)$ singlet-octet mixing angle$\theta$ is about zero. The effects of the $U_A(1)$ breaking on the baryonnumber one and two systems are also studied.Comment: 12 pages, LaTeX, 2 eps figures, Talk given at the Joint  Japan-Australia Workshop on Quarks, Hadrons and Nuclei, Adelaide, Australia,  Nov. 15-24, 199

h-Meson Decays and Strong UA(1) Breaking in the Three-flavour Nambu - Jona-Lasinio Model