We study chiral symmetry breaking in nuclear matter. For the dynamics we use a class of quark models with a chiral invariant confining potential. The mass gap equation is obtained when we minimize the energy of the matter with respect to the chiral angle φ and to the quark wave function in the nucleon. At low nuclear density ρ, we find that the chiral angle decreases slightly, the nucleon swells and the nucleon mass decreases. However, for the density of nuclear matter, we find that the chiral angle suffers an enhancement. We briefly discuss the physical consequences of this effect and its independence of the microscopic quark model.

• Received 6 April 1993

DOI:https://doi.org/10.1103/PhysRevLett.72.1600