Analysis of the Pion Wave Function in Light-Cone Formalism
  Several general constraints are suggested to analyze the pionic valence-state wave function. It is found that the present model wave functions used in light-cone formalism of perturbative quantum chromodynamics have failed these requirements to fit the pionic form factor data and the reasonable valence-state structure function which does not exceed the pionic structure function data for $x \rightarrow 1$ simultaneously. Furthermore, it is pointed out that there is a possibility to find model wave functions which can satisfy all of general constraints. Also we show that there are two higher helicity $(\lambda_{1} + \lambda_{2} =\pm1)$ components in the light-cone wave function for the pion as a natural consequence from the Melosh rotation and it is speculated that these components should be incorporated into the perturbative quantum chromodynamics. 
Tao Huang, Bo-Qiang Ma and Qi-Xing Shen