Exact nature of the lightest U(1)-charged vector states in SU(3) Yang–Mills with a fundamental Higgs

Determine the exact nature and internal structure of the lightest U(1)-charged vector states observed in lattice simulations of SU(3) Yang–Mills theory coupled to a Higgs field in the fundamental representation in the Brout–Englert–Higgs–like regime, and ascertain whether these states can be quantitatively described within Fröhlich–Morchio–Strocchi–augmented perturbation theory.

Background

The paper studies the observable spectrum of SU(3) Yang–Mills theory coupled to a Higgs field in the fundamental representation, focusing on gauge-invariant composite states rather than elementary fields. Lattice results reveal a rich spectrum that differs qualitatively from perturbation theory, consistent with expectations from the Fröhlich–Morchio–Strocchi (FMS) mechanism.

In the charged sector, the authors observe a degenerate pair of stable vector states that are substantially heavier than the lightest uncharged vector state. Simple explanations such as s-channel exchange of elementary particles or a naive constituent model do not account for their mass or degeneracy. Consequently, whether FMS-augmented perturbation theory can quantitatively capture these charged states—and what their precise structure is—remains unresolved.