When can hadronic loops scuttle the Okubo-Zweig-Iizuka rule?

We have improved and extended our previous calculations of hadronic loop contributions to meson propagators. As we anticipated from our study of the vector mesons, systematic cancellations among the loops, which are crucial for the preservation of the Okubo-Zweig-Iizuka rule, continue to occur in all the low-lying nonets except $0^{++}$. The failure of the cancellation mechanism in this sector has striking repercussions for the masses and couplings of the scalar mesons. We also present calculations of loop-induced SU(3) violation in the low-lying nonets.