Diquark

In quark–diquark models, a diquark, or diquark correlation/clustering, is the hypothetical state of two quarks grouped inside a baryon (that consists of three quarks) (Lichtenberg 1982). The diquark is often treated as a single particle with which the third quark interacts via the strong interaction. The existence of diquarks inside the nucleons is a disputed issue, but it helps to explain some nucleon properties and to reproduce experimental data sensitive to the nucleon structure. Diquark–antidiquark pairs have also been advanced for anomalous particles such as the X(3872).