NJL model on the light cone and pion structure function

Abstract

The NJL model is formulated on the light cone. Using the 1/N expansion to solve the fermionic constraint, an effective 4-fermi lagrangian is derived. Pionic properties are investigated using this lagrangian, and the formal equivalence to the equal-time formulation is demonstrated. Two regularization schemes in terms of light-cone variables are discussed: An extension of the 'invariant mass cut-off scheme', and a transverse momentum cut-off scheme. It is shown that the first one is equivalent to the covariant 3-momentum cut-off (dispersion cut-off) scheme in the equal-time formulation. As an application the structure function of the pion is studied in both regularization schemes.