Spin Structure of the Pion in a Light-Cone Representation

Abstract

The spin structure of the pion is discussed by transforming the wave function for the pion in the naive quark model into a light-cone representation. It is shown that there are higher helicity ($λ_{1}+λ_{2}=\pm1$) states in the full light-cone wave function for the pion besides the ordinary helicity ($λ_{1}+λ_{2}=0$) component wave functions as a consequence from the Melosh rotation relating spin states in light-front dynamics and those in instant-form dynamics. Some low energy properties of the pion, such as the electromagnetic form factor, the charged mean square radius, and the weak decay constant, could be interrelated in this representation with reasonable parameters.