An asymptotic safety scenario for gauged chiral Higgs-Yukawa models

TL;DR

This paper proposes a new asymptotic safety scenario for gauged chiral Higgs-Yukawa models, revealing a weak-coupling fixed point with nonperturbative features that could lead to ultraviolet complete theories compatible with observed particle physics.

Contribution

It introduces a novel weak-coupling fixed point in chiral Higgs-Yukawa models, enabling ultraviolet completeness with nonperturbative effects and realistic mass ratios.

Findings

Discovery of a weak-coupling fixed point with asymptotic freedom in all couplings.

Ultraviolet stability achieved through nonperturbative threshold effects.

Potential for realistic Higgs and top mass ratios via specific RG trajectories.

Abstract

We investigate chiral Higgs-Yukawa models with a non-abelian gauged left-handed sector reminiscent to a sub-sector of the standard model. We discover a new weak-coupling fixed-point behavior that allows for ultraviolet complete RG trajectories which can be connected with a conventional long-range infrared behavior in the Higgs phase. This non-trivial ultraviolet behavior is characterized by asymptotic freedom in all interaction couplings, but a quasi conformal behavior in all mass-like parameters. The stable microscopic scalar potential asymptotically approaches flatness in the ultraviolet, however, with a non-vanishing minimum increasing inversely proportional to the asymptotically free gauge coupling. This gives rise to nonperturbative -- though weak-coupling -- threshold effects which induce ultraviolet stability along a line of fixed points. Despite the weak-coupling properties, the system exhibits non-Gaussian features which are distinctly different from its standard perturbative counterpart: e.g., on a branch of the line of fixed points, we find linear instead of quadratically running renormalization constants. Whereas the Fermi constant and the top mass are naturally of the same order of magnitude, our model generically allows for light Higgs boson masses. Realistic mass ratios are related to particular RG trajectories with a "walking" mid-momentum regime.