FIELD-THEORETICAL DESCRIPTION OF NUCLEAR-MATTER WITH ONLY THE PION-NUCLEON INTERACTION

A relativistic Lagrangian for the nuclear matter consisting of nucleon s and pions with a pseudoscalar interaction term. is considered. It is shown that a nonrelativistic reduction of the problem automatically i ntroduces a Lorentz scalar, isoscalar coupling of nucleons with two co rrelated pions. The corresponding Hamiltonian is used to study the pro perties of infinite nuclear matter nonperturbatively, treating both th e nucleons and pions as quantized fields. The model is shown to reprod uce the characteristic nuclear matter properties very nicely without t he necessity of sigma and omega fields, as is usually done in the mean field Walecka model. The corresponding equation of state for zero tem perature nuclear matter is calculated and is shown to be consistent wi th the known phenomenological equations of state. The binding energy o f nuclear matter is calculated to be 15.3 MeV at a saturation density of 0.153 fm(-3). The model reproduces a softer nuclear matter with the incompressibility of 134 MeV.