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 perform a theoretical analysis of the semileptonic decays $\eta^{(\prime)}\to \pi^0 \ell^+ \ell^-$ and $\eta' \to \eta \ell^+ \ell^-$, where $\ell = e,\mu$, via a charge-conjugation-conserving two-photon mechanism. The underlyingform factors are modeled using vector-meson dominance, phenomenological input,and $\mathrm{U}(3)$ flavor symmetry. We consider both a monopole and a dipolemodel, the latter tailored such that the expected high-energy behavior isensured. Furthermore, we benchmark the effect of $S$-wave rescatteringcontributions to the decays. We infer significant effects of the form factorsneglected in the literature so far, still finding branching ratios of thevarious decays well below the current experimental upper limits.

The semileptonic decays $\eta^{(\prime)} \to \pi^0 \ell^+ \ell^-$ and $\eta' \to \eta \ell^+ \ell^-$ in the standard model