An estimate for 12-quark cluster probabilities

The discovery of the European Muon Collaboration (EMC) effect (1) was a surprise. It showed that the ratio of the structure function for iron and that for deuteron was significantly different from unity. This contradicted the then prevailing nuclear picture that a nucleus could be considered as an ensemble of individual nucleons, which retained their identity. Subsequent deep inelastic experiments with both muons and electrons have confirmed this effect both in iron and other nuclei (2-6).