Cosmological Implications of a Scale Invariant Standard Model

TL;DR

This paper explores a scale-invariant extension of the Standard Model coupled with modified gravity, which naturally generates particle masses and dark energy, offering insights into cosmology and particle physics.

Contribution

It introduces a scale-invariant Standard Model with modified gravity, explaining mass generation and dark energy without a cosmological constant.

Findings

Predicts a very small Higgs mass in the simplest model

Disappearance of the Higgs particle in the local scale invariance version

Introduction of a massive vector boson in the local scale invariant model

Abstract

We generalize the standard model of particle physics such it displays global scale invariance. The gravitational action is also suitably modified such that it respects this symmetry. This model is interesting since the cosmological constant term is absent in the action. We find that the scale symmetry is broken by the recently introduced cosmological symmetry breaking mechanism. This simultaneously generates all the dimensionful parameters such as the Newton's gravitational constant, the particle masses and the vacuum or dark energy. We find that in its simplest version the model predicts the Higgs mass to be very small, which is ruled out experimentally. We further generalize the model such that it displays local scale invariance. In this case the Higgs particle disappears from the particle spectrum and instead we find a very massive vector boson. Hence the model gives a consistent description of particle physics phenomenology as well as fits the cosmological dark energy.