Fifth forces and discrete symmetry breaking

Millington, P

Abstract

Modifications of general relativity often involve coupling additional scalar fields to the Ricci scalar, leading to scalar-tensor theories of Brans-Dicke type. If the additional scalar fields are light, they can give rise to long-range fifth forces, which are subject to stringent constraints from local tests of gravity. In this talk, we show that Yukawa-like fifth forces only arise for the Standard Model (SM) due to a mass mixing of the additional scalar with the Higgs field, and we emphasise the pivotal role played by discrete and continuous symmetry breaking. Quite remarkably, if one assumes that sufficiently light, non-minimally coupled scalar fields exist in nature, the non-observation of fifth forces has the potential to tell us about the structure of the SM Higgs sector and the origin of its symmetry breaking. Moreover, with these observations, we argue that certain classes of scalar-tensor theories are, up to and including their dimension-four operators, equivalent to Higgs-portal theories. In this way, ultra-light dark matter models may also exhibit fifth-force phenomenology, and we consider the impact on the dynamics of disk galaxies as an example.

Citation

Millington, P. Fifth forces and discrete symmetry breaking. Presented at 6th Symposium on Prospects in the Physics of Discrete Symmetries - DISCRETE 2018, Vienna, Austria

• Presentation Conference Type: Conference Paper (published)
• Conference Name: 6th Symposium on Prospects in the Physics of Discrete Symmetries - DISCRETE 2018
• Acceptance Date: Jun 30, 2020
• Online Publication Date: Sep 11, 2020
• Publication Date: 2020
• Deposit Date: Sep 13, 2020
• Publicly Available Date: Sep 14, 2020
• Journal: Journal of Physics: Conference Series
• Print ISSN: 1742-6588
• Electronic ISSN: 1742-6596
• Publisher: IOP Publishing
• Volume: 1586
• Article Number: 012024
• DOI: https://doi.org/10.1088/1742-6596/1586/1/012024
• Keywords: General Physics and Astronomy
• Public URL: https://nottingham-repository.worktribe.com/output/4902076
• Publisher URL: https://iopscience.iop.org/article/10.1088/1742-6596/1586/1/012024