8 AdS / QCD at the correlator level

We derive and analyze predictions of both the hard-wall and dilaton soft-wall AdS/QCD approximations for the scalar glueball correlator and decay constants. We confront the results with QCD information from the lattice, the operator product expansion (OPE), a hypothetical UV gluon mass associated with the short-distance behavior of the heavy-quark potential, and a low-energy theorem based on the anomalous dilatational Ward identity. Both duals turn out to encode complementary aspects of the above, nonperturbative QCD physics. The OPE Wilson coefficients, in particular, are shown to provide a challenging testing ground for the impact of the strongly coupled holographic UV dynamics on dual gravity predictions.