Several years ago we have proposed a manifestly covariant $\tilde{ U}(12)_{ SF}$-classification scheme of hadrons, which maintains the successful $SU(6)_{ SF}\otimes O(3)_{ L}$ framework in Non-Relativistic Quark Model and is also reconcilable with the mechanism of Spontaneously-Broken Chiral Symmetry in Relativistic Field Theoretical Models. The essential point here is to notice the overlooked freedom of the $SU(2)_{ \rho}$-spin for (confined) light quarks, which leads to existence of new type of ``exotic'' hadrons, called ``chiralons'' and to a selection rule, $\rho_{ 3}$-line rule, on the spectator quark line. A series of puzzling new hadrons recently observed such as X(3872)-meson family and $\Theta (1540)$ and so on are possibly classified mostly as chiralons.
Categories: hep-ph