Using data acquired with the CLEO-c detector at the CESR e+e- collider, we measure branching fractions for J/ψ, ψ(2S), and ψ(3770) decays to γπ0, γη, and γη′. Defining Rn B[ψ(nS)→γη]/B[ψ(nS)→γη′], we obtain R1=(21.1±0.9)% and, unexpectedly, an order of magnitude smaller limit, R2<1.8% at 90% C.L. We also use J/ψ→γη′ events to determine branching fractions of improved precision for the five most copious η′ decay modes.
ASJC Scopus subject areas
- Nuclear and High Energy Physics