The role of the η, η′ and ε mesons in the decays of the γ-family is investigated. By analogy with the ψ system these light mesons, because of their heavy-quark content, are expected to exhibit special affinity for γ. The effect, however, is anticipated to be much less pronounced, for γ than it is for ψ. We predict Γ (γ′→(η, ππ)γ)≲2 keV, a value consistent with a bound of ≅10 keV derived from the observed ratio of the μ+μ- signal for γ and γ′. The latter data also favor a value of Λ(γ→direct hadrons) of at least 1 keV in contrast to expectations from duality.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Nuclear and High Energy Physics
- Astronomy and Astrophysics