OZI rule

The OZI rule or Zweig's rule is a rule of quantum chromodynamics and explains why some particle decays occur less often than expected. It was proposed independently by Susumu Ōkubo , George Zweig, and Jugoro Iizuka in the 1960s. It says that any process of strong interaction is suppressed, the Feynman diagram of which can be split into two parts, connected only by the internal lines of gluons .

One example is the decay of the φ meson into three pions , . One would expect that this would cause the other decays of the φ meson with lower energy transfers such as As the decay into two kaons , dominated. Experimentally, however, it is found that the φ meson decays into kaons in 84% of all cases, so the decay into pions is suppressed. ${\displaystyle \phi \rightarrow \pi ^{+}+\pi ^{-}+\pi ^{0}}$ ${\displaystyle \phi \rightarrow K^{+}+K^{-}}$

An explanation for the OZI rule can be derived from the current coupling constant of the QCD. The “constant” decreases with increasing energy, and for the decays mentioned in the OZI rule, the gluons require high energies (at least the energy of the masses of the hadrons that arise from them).

See also

• J / ψ meson

literature

• David Griffiths, Elementary Particle Physics , Akademie Verlag, Berlin, 1996