OZI rule

The OZI rule or branch - rule is a rule of quantum chromodynamics and explains why some Teilchenzerfälle occur less often than expected. She became independent by Susumu Okubo, George Zweig proposed and Jugoro Iizuka in the 1960s. It says that every process of the strong interaction is suppressed, the Feynman diagram can be divided into two parts, which are connected only by the internal lines of gluons.

An example of this is the decay of the φ - meson into three pions. One would expect that these other decays of the φ meson with lower energy carries, such as the decay into two kaons, dominates. Experimentally, however, notes that the φ -meson decays in 84 % of cases in kaons, the decay is thus suppressed in pions.

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