The effect of renormalization in a finite massive theory
The fact that a theory is finite does not preclude the possibility of making finite renormalizations. With this in mind, we consider massive N = 4 super Yang–Mills theory, a model known to have a vanishing β function and to be finite at one-loop order when one uses the formulation using N = 1 superfields. The mass that appears in the Lagrangian is not a pole of the propagator when radiative effects are included; we fix the position of this pole and then discuss how the effective coupling constant in the theory depends on this pole mass. This procedure is akin to the original Gell-Mann–Low approach to the renormalization group. A one-loop calculation indicates that the effective coupling vanishes as the pole mass goes to zero and diverges for large values of the pole mass.