Covariant Level-Classification Scheme and Chiral Symmetry
  Starting from the bi-local Klein-Gordon Equation with spin-independent squared-mass operator, we give a covariant quark representation of general composite meson systems with definite Lorentz transformation properties. For benefit of this representation we are able to deduce automatically the transformation rules of composite mesons for general symmetry operations from those of constituent (exciton) quarks. Applying this we investigate especially physical implication of chiral symmetry for the meson systems, and present a covariant level-classification scheme, leading to a possible existence of new meson multiplets of "chiralons." 
Shin Ishida (Nihon U.), Muneyuki Ishida (TITech) and Tomohito Maeda   (Nihon U.)