Green’s function in the color field of a large nucleus

Abstract

We compute the Green's function for scalars, fermions, and vectors in the color field associated with the infinite momentum frame wave function of a large nucleus. Expectation values of this wave function can be computed by integrating over random orientations of the valence quark charge density. This relates the Green's functions to correlation functions of a two-dimensional, ultraviolet finite, field theory. We show how one can compute the sea quark distribution functions and explicitly compute them in the kinematic range of transverse momenta, ${\mathrm{\ensuremath{\alpha}}}_{\mathit{s}}^{2}$${\mathrm{\ensuremath{\mu}}}^{2}$\ensuremath{\ll}${\mathit{k}}_{\mathit{t}}^{2}$\ensuremath{\ll}${\mathrm{\ensuremath{\mu}}}^{2}$, where ${\mathrm{\ensuremath{\mu}}}^{2}$ is the average color charge squared per unit area. When ${\mathit{m}}_{\mathrm{quark}}^{2}$\ensuremath{\ll}${\mathrm{\ensuremath{\mu}}}^{2}$\ensuremath{\sim}${\mathit{A}}^{1/3}$, the sea quark contribution to the infinite momentum frame wave function saturates at a value that is the same as that for massless sea quarks.