  Predictions of glueball decay rates in the holographic Witten-Sakai-Sugimoto
model for low-energy QCD can be uniquely extended to include finite quark
masses up to an as yet undetermined parameter in the coupling of glueballs to
the nonanomalous part of the pseudoscalar mass terms. The assumption of a
universal coupling of glueballs to mass terms of the full nonet of pseudoscalar
mesons leads to flavor asymmetries in the decay rates of scalar glueballs that
agree well with experimental data for the glueball candidate $f_0(1710)$ and
implies a vanishing decay rate into $\eta\eta'$ pairs, for which only upper
bounds for the $f_0(1710)$ meson are known at present from experiment. Relaxing
this assumption, the holographic model gives a tight correlation between the
decay rates into pairs of pseudo-Goldstone bosons of same type and $\eta\eta'$
pairs. If $\Gamma(G\to KK)/\Gamma(G\to\pi\pi)$ is kept within the range
reported currently by the Particle Data Group for the $f_0(1710)$ meson, the
rate $\Gamma(G\to\eta\eta')/\Gamma(G\to\pi\pi)$ is predicted to be $\lesssim
0.04$. The corresponding situation for $f_0(1500)$ is also discussed, which
however is found to be much less compatible with the interpretation of a
largely unmixed glueball.
