Dynamical Lorentz and CPT symmetry breaking in a 4D four-fermion model

Abstract

In a 4D chiral Thirring model we analyse the possibility that radiative corrections may produce spontaneous breaking of Lorentz and CPT symmetry. By studying the effective potential, we verified that the chiral current $\barψγ^μ γ_5 ψ$ may assume a nonzero vacuum expectation value which triggers the Lorentz and CPT violations. Furthermore, by making fluctuations on the minimum of the potential we dynamically induce a bumblebee like model containing a Chern-Simons term.

Small modifications in the text and new references added, 12 pages, 4 figures, revtex4. To appear in Phys. Rev. D