Diquarks as a solution to some difficulties of the quark model

As a reaction to the difficulties of the ordinary quark model we propose the diquark model for hadrons. The number of elementary objects in the diquark model is larger than in the quark model, for aside from the usual three quarks one finds here 18 new objects—diquarks—that can be regarded as two quarks glued together. The spin of quarks is ${\frac{1}{2}}^{+}$. The spins of diquarks are $0^{+}$ and $1^{+}$. From the point of view of unitary symmetry the diquarks are the spinors from the irreducible representations $\overline{3}$ and 6 in $3\times 3=\overline{3}+6$. In a larger group-theoretical framework of SU(6) symmetry (that mixes unitary and spin degrees of freedom), the diquarks are spinors from the irreducible representations 15 and 21 in 6 × 6 = 15 + 21.