Novel Six-Quark Hidden-Color Dibaryon States in QCD

The recent observation of a hadronic resonance $d^{\ast }$ in the proton-neutron system with isospin $I=0$ and spin-parity $J^P=3^{+}$ raises the possibility of producing other novel six-quark dibaryon configurations allowed by QCD. A dramatic example of an exotic six-quark color-singlet system is the charge $Q=+4$, isospin I=3, $I^z=+3$ $\mathrm{\mid }uuuuuu>$ state which couples strongly to ${\mathrm{\Delta }}^{++}$ + ${\mathrm{\Delta }}^{++}\mathrm{.}$ The width and decay properties of such six-quark resonances could be regarded as manifestations of “hidden-color” six-quark configurations, a first-principle prediction of QCD – SU(3)-color gauge theory for the deuteron distribution amplitude. Other implications and possible future experiments are discussed.