We address and solve the long-standing gauge-invariance problem of the nucleon spin structure. Explicitly gauge-invariant spin and orbital angular momentum operators of quarks and gluons are… (More)

Based on the quark propagator in the instanton dilute liquid approximation, we calculate analytically the quark condensate < q̄q >, the mixed quark gluon condensate gs < q̄Gμνσ q > and the four quark… (More)

A nonlinear realization of SU(2) chiral symmetry spontaneous breaking approach is developed in the composite operator formalism. The properties of nuclear matter, the pion and the quark condensates… (More)

A nonlinear realization of SU(2) chiral symmetry spontaneous breaking approach is developed in the composite operator formalism. A Lagrangian including quark, gluon and Goldstone boson degrees of… (More)

Considering the effect of the volume of nucleons, a Lagrangian density is given and the first order self-energy of the nucleon has been calculated. Furthermore, the equation of state of nuclear… (More)

We examine the conventional picture that gluons carry about half of the nucleon momentum in the asymptotic limit. We show that this large fraction is due to an unsuitable definition of the gluon… (More)