Physical parameters and renormalization of U(1) ^{a} × U (1) ^{b} models
Abstract
We analyze the structure of models with unbroken and spontaneously broken U(1) ^{a} × U(1) ^{b} gauge symmetry. We show that the quantum corrections to the 2 N gauge charges, with N = number of fermions + number of scalars, can be absorbed in the redefinition of three independent gauge couplings ( g^{a}, g^{b}, and g^{ab}). We establish the (oneloop) conditions on the matter content for g^{ab} = 0 (a value usually assumed in the literature) and we show that in the minimal extensions of the Standard Model with an extra U(1) symmetry the choice g^{ab} = 0 is not stable under radiative corrections induced by the standard Higgs fields. Moreover, g^{ab} = 0 to all orders seems to require an exact symmetry. The spontaneous breaking of the gauge symmetry induces further mixing between the two gauge bosons and introduces a fourth independent physical parameter. A consequence of our analysis is that the usual treelevel description with only three physical parameters (i.e., two gauge couplings and one gauge boson mixing angle) is not in general a justified zero order limit of the treatment including radiative corrections.
 Publication:

Nuclear Physics B
 Pub Date:
 February 1995
 DOI:
 10.1016/05503213(95)005116
 arXiv:
 arXiv:hepph/9507455
 Bibcode:
 1995NuPhB.456..531D
 Keywords:

 High Energy Physics  Phenomenology
 EPrint:
 24 pages, tex, 1 figure