Renormalization and radiative corrections to masses in a general Yukawa model

M. Fox, W. Grimus, M. Loeschner

We consider a model with arbitrary numbers of Majorana fermion fields and real scalar fields phi(a), general Yukawa couplings and a Z(4) symmetry that forbids linear and trilinear terms in the scalar potential. Moreover, fermions become massive only after spontaneous symmetry breaking of the Z(4) symmetry by vacuum expectation values (VEVs) of the phi(a). Introducing the shifted fields h(a) whose VEVs vanish, (MS) over bar renormalization of the parameters of the unbroken theory suffices to make the theory finite. However, in this way, beyond tree level it is necessary to perform finite shifts of the tree-level VEVs, induced by the finite parts of the tadpole diagrams, in order to ensure vanishing one point functions of the h(a). Moreover, adapting the renormalization scheme to a situation with many scalars and VEVs, we consider the physical fermion and scalar masses as derived quantities, i.e. as functions of the coupling constants and VEVs. Consequently, the masses have to be computed order by order in a perturbative expansion. In this scheme, we compute the self-energies of fermions and bosons and show how to obtain the respective one-loop contributions to the tree-level masses. Furthermore, we discuss the modification of our results in the case of Dirac fermions and investigate, by way of an example, the effects of a flavor symmetry group.

Particle Physics
International Journal of Modern Physics A
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Publication date
Peer reviewed
Austrian Fields of Science 2012
103012 High energy physics, 103034 Particle physics, 103036 Theoretical physics
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