Author Vieri Mastropietro
Title Renormalization Group and Ward Identities in regularized
QED in four dimensions
We analyze, by Renormalization Group methods, Euclidean
QED in four dimensions with any value, including zero, of the fermion mass
and an ultraviolet momentum cut-off.
The $n$-point functions, expressed by convergent series, do not verify the
Ward Identities, as a consequence of the breaking of the local gauge symmetry
due to the momentum regularizations. We will prove nevertheless that,
if the charge renormalization is taken into account,
Ward Identities are "almost" restored for momenta far enough from the cut-off scale, in the sense that
their violation is of the order of the inverse of the cut-off.
Keywords QED, Ward Identities, Constructive QFT
Last modified: Sat Feb 18 14:42:23 CET 2007