Four quark meson postulated by physicists

Physicists at the Belle experiment in Japan have suggested the possibility of the existence of a four-quark meson. This is being used to explain the results of experiments on colliding electrons and positrons at the KEK and BaBar laboratories in Japan and at the Standford linear accelerator respectively. The decay path of these mesons is such that the original particle observed, dubbed Z(4430), must contain four quarks as opposed to the two-quark model predicted by quantum chromodynamics (QCD).

See Physics World.