Poincare Protection for a Natural Electroweak Scale

TL;DR

The paper argues that the electroweak scale can be technically natural if heavy UV sectors are present and coupled weakly to the SM, with an enhanced Poincaré symmetry protecting the light sector in the decoupling limit. It provides a concrete mechanism for naturalness via small mixing couplings $\lambda_{\rm mix}$ that restore a product Poincaré symmetry, and demonstrates this with an explicit invisible axion model that also addresses the strong-CP problem and dark matter. The work further clarifies the relationship between Poincaré protection and scale invariance, showing that scale invariance alone is insufficient to guarantee radiative stability and that the maximal stable hierarchy is set by the largest mixing coupling. Overall, the framework offers a path to embed heavy, well-motivated UV physics into the SM without reintroducing large radiative corrections to the weak scale, consistent with LHC null results.

Abstract

We discuss a class of technically-natural UV extensions of the Standard Model in which the electroweak scale is shielded from large radiative corrections from heavy UV physics due to an enhanced Poincare symmetry. Such heavy sectors can be invoked to provide solutions to known shortcomings of the Standard Model, such the strong-CP problem, the absence of dark matter, and the lack of neutrino masses. We discuss the relationship to scale-invariant models.