Dynamical symmetry breaking of U(N)symmetric gauge theory in the 1N expansion
Abstract
A gauge theory with U(N) symmetry is studied in the largeN limit to all orders in the scalar selfcoupling, and to lowest nontrivial order in the gauge coupling. Unlike the 1N expansion of the scalar field theory, the effective potential is found to be always real, although it can be mutiplevalued. Furthermore, there is a region in the couplingconstant space where symmetry is broken spontaneously involving two separate phase transitions, one of the first kind and one of the second kind. This phenomenon persists for arbitrarily small (finite) gauge coupling as a genuine feature of the 1N expansion, exhibiting much more of the nonlinear structure of the complete theory than found in ordinary perturbation expansions. A comparison is made between the spontaneous symmetry breaking found in the 1N expansion and that of other symmetrybreaking schemes, which are of the Goldstone, Higgs, or ColemanWeinberg type. Here the vectorscalarboson mass ratio, M_{V}^{2}M_{S}^{2}, is of O(g^{2}), which is contrasted with Higgs and ColemanWeinberg mechanisms, for which M_{V}^{2}M_{S}^{2} is of O(1) and O(g^{2}), respectively, where g is the gauge coupling.
 Publication:

Physical Review D
 Pub Date:
 September 1976
 DOI:
 10.1103/PhysRevD.14.1587
 Bibcode:
 1976PhRvD..14.1587K