Diquark-induced Short-Range Correlations and Hidden-Color Singlets in Nuclear Wavefunctions

A diquark bond formed from valence quarks across a nucleon-nucleon pair has been proposed as the fundamental quantum chromodynamics (QCD) physics causing short-range correlations (SRC) in nuclei. SRC nucleon-nucleon pairs and the nucleon shell model are the basis for most of nuclear structure, with SRC accounting for 20% of the nucleons in a nucleus. While SRC have been extensively studied both experimentally and theoretically, notably by the CLAS collaboration in recent years, their underlying cause at the QCD level has remained a mystery. The diquark formation model, if shown to be the cause of SRC, represents a breakdown of the assumption of scale separation in effective field theories. Rather than a boundary between scales, however fuzzy and broad, a case is made in this work for diquark formation as a direct breakthrough of the underlying theory, capturing 20% of the physics of nuclear structure and causing the distortion of structure functions as observed in the EMC effect. Diquark based hidden-color singlets in nuclear wavefunctions are also discussed, in particular the "hexadiquark" Fock state in helium-4.