Eta-eta' mixing from V->Pgamma and J/psi->VP decays

Abstract

The $η$-$η^\prime$ pseudoscalar mixing angle and the gluonium content of the $η^\prime$ meson are deduced from an updated phenomenological analysis of $V\to Pγ$ and $J/ψ\to VP$ decays. In absence of gluonium, the value of the mixing angle in the quark-flavour basis is found to be $ϕ_P=(41.5\pm 1.2)^\circ$ from $V\to Pγ$ and $ϕ_P=(40.5\pm 2.4)^\circ$ from $J/ψ\to VP$. In presence of gluonium, the values for the mixing angle and the gluonic content of the $η^\prime$ wave function are $ϕ_P=(41.4\pm 1.3)^\circ$ and $Z^2_{η^\prime}=0.04\pm 0.09$ from $V\to Pγ$ and $ϕ_P=(44.5\pm 4.3)^\circ$ and $Z^2_{η^\prime}=0.28\pm 0.21$ from $J/ψ\to VP$, respectively.

8 pages, uses appolb style. Talk presented at the Symposium on Meson Physics, Cracow, Poland, 1-4 October 2008