出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：Since the early days of QCD, it has been argued that inside hadrons quarks organise into substructures.
Among those, popular pictures of various phenomena (including exotica and colour
superconductivity) give a prominent role to diquarks, i.e. to colour antitriplet combinations of
two quarks. Using a gauge-invariant setup, which combines the diquark with a static quark, we
study spatial correlations of the two light quarks inside the diquark. After illustrating the setup,
we discuss our first results for both the scalar (“good”) and the spin one (“bad”) diquark channels.
In a regime in which mp ' 830 MeV, our data show unambiguously that a scalar diquark forms
with a size of ' 0.9 fm. For the vector diquark we are able to put a lower bound of 4.1(7) fm on
its size. We also investigate the mass splitting between the good and the bad diquark; our findings
are compatible with phenomenologically inspired predictions for this quantity.
