Eur. Phys. J. C (2006) 47: 187-205
https://doi.org/10.1140/epjc/s2006-02537-3

Theoretical Physics

Z^′ and the Appelquist–Carrazzone decoupling

Institute of Theoretical Physics, Warsaw University, Hoża 69, 00-681, Warsaw, Poland

^* e-mail: Piotr.Chankowski@fuw.edu.pl

Received: 23 January 2006
Published online: 19 April 2006

Abstract

We consider the electroweak theory with an additional neutral vector boson Z^′ at one loop. We propose a renormalization scheme which makes the decoupling of heavy Z^′ effects manifest. The proposed scheme justifies the usual procedure of performing fits to the electroweak data by combining the full SM loop corrections to observables with the tree-level corrections due to the extended gauge structure. Using this scheme we discuss in the model with extra an U(1)^′ group factor one-loop results for the ρ parameters defined in several different ways.