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Author Vieri Mastropietro

Title Renormalization Group and Ward Identities in regularized QED in four dimensions

Abstract 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

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Vieri Mastropietro

Last modified: Sat Feb 18 14:42:23 CET 2007