  The OZI rule is prominent in hadronic phenomena only because OZI violation is
typically an order of magnitude smaller than expected from large N_c arguments.
With its standard ^3P_0 pair creation operator for hadronic decays by flux tube
breaking, the quark model respects the OZI rule at tree level and exhibits the
cancellations between OZI-violating meson loop diagrams required for this
dramatic suppression. However, if the quark model explanation for these
cancellations is correct, then OZI violation would be expected to be large in
the nonet with the same quantum numbers as the pair creation operator: the
0^{++} mesons. Experiment is currently unable to identify these mesons, but we
report here on a lattice QCD calculation which confirms that the OZI rule
arises from QCD in the vector and axial vector mesons as observed, and finds a
large violation of the rule in the scalar mesons as anticipated by the quark
model. In view of this result, we make some remarks on possible connections
between the ^3P_0 pair creation model, scalar mesons, and the U_A(1) anomaly
responsible for the large OZI violation which drives the \eta' mass. In
particular, we note that our result favors the large N_c and not the instanton
interpretation of the solution to the \eta' mass problem.
