Massive vector bosons: is the geometrical interpretation as a spontaneously broken gauge theory possible at all scales?

TL;DR

This paper examines whether the geometric interpretation of massive vector bosons as spontaneously broken gauge theories remains valid at all energy scales, revealing that it generally does not under RG flow, but physical consistency persists.

Contribution

It demonstrates that the geometrical interpretation of massive vector bosons is not preserved under RG flow in the U(1)-Higgs model when using minimal subtraction renormalization.

Findings

Geometrical interpretation is lost under RG flow with minimal subtraction.

BRST-invariance of the Lagrangian is not maintained under RG flow.

Physical consistency remains intact under RG flow.

Abstract

The usual derivation of the Lagrangian of a model for massive vector bosons, by spontaneous symmetry breaking of a gauge theory, implies that the prefactors of the various interaction terms are uniquely determined functions of the coupling constant(s) and the masses. Since, under the renormalization group (RG) flow, different interaction terms get different loop-corrections, it is uncertain, whether these functions remain fixed under this flow. We investigate this question for the $U(1)$-Higgs-model to 1-loop order in the framework of Epstein-Glaser renormalization. Our main result reads: choosing the renormalization mass scale(s) in a way corresponding to the minimal subtraction scheme, the geometrical interpretation as a spontaneously broken gauge theory gets lost under the RG-flow. This holds also for the clearly stronger property of BRST-invariance of the Lagrangian. On the other hand we prove that physical consistency, which is a weak form of BRST-invariance of the time-ordered products, is maintained under the RG-flow.