Okubo-Zweig-Iizuka Rule Violation and Possible Explanations

Abstract

Violations of the Okubo-Zweig-Iizuka (OZI) rule in $s\bar{s}<->n\bar{n}=1/2(u\bar{u}+d\bar{d})$ mixing and $\varphi$ production from nucleon-antinucleon annihilation are reviewed. Possible explanations are examined. We conclude that the two-step hadronic loops can explain these OZI violations naturally with proper consideration of cancellations between loops. No conclusive evidence exists for glueball states, $s\bar{s}n\bar{n}$ four quark states, instanton effects, and strange quarks in nucleon.

Comments: 16 pages incluing 3 postscript figures