THE NUCLEAR SPIN-ORBIT FORCE IN CHIRAL EFFECTIVE-FIELD THEORIES

A compelling feature of relativistic mean-field phenomenology has been the reproduction of spin-orbit splittings in finite nuclei after fitt ing only to equilibrium properties of infinite nuclear matter. This su ccessful result occurs when the velocity dependence of the equivalent central potential that leads to saturation arises primarily because of a reduced nucleon effective mass, The spin-orbit interaction is then also specified when one works in a four-component Dirac framework. Her e the nature of the spin-orbit force in more general chiral effective field theories of nuclei is examined, with an emphasis on the role of the tensor coupling of the isoscalar vector meson (omega)to the nucleo n. (C) 1998 Published by Elsevier Science B.V.