Scale-Invariant Scalar Field Dark Matter
Through the Higgs-Portal
Catarina Cosme
Abstract We introduce an oscillating scalar field coupled to the Higgs that can
account for all dark matter in the Universe. Due to an underlying scale invariance of
this model, the dark scalar only acquires mass after the electroweak phase transition.
We discuss the dynamics of this dark matter candidate, showing that it behaves like
dark radiation until the electroweak phase transition and like non-relativistic matter
afterwards. In the case of a negative coupling to the Higgs field, the scalar gets a
vacuum expectation value after the electroweak phase transition and may decay into
photons although being sufficiently long-lived to account for dark matter. We show
that, within this scenario, for a mass of 7 keV, the model can explain the observed
galactic and extra-galactic 3.5 keV X-ray line. Nevertheless, it will be very difficult
to probe this model in the laboratory in the near future. This proceedings paper is
based on Refs. Cosme et al. (J High Energy Phys 1805, 129, 2018; Phys Lett B 781,
639, 2018).
Keywords Dark matter · Scalar field · Higgs boson
1 Introduction
Dark matter (DM) is one of the greatest unsolved questions in Physics. This
invisible form of matter constitutes almost 27% of the Universe’s energy density
content and is required to explain its structure on large scales, the anisotropies
in the Cosmic Microwave Background (CMB), and the galaxy rotation curves.
Despite a large number of candidates that arise in theories beyond the Standard
Model of Particle Physics (SM), the origin and the constitution of DM remain
unknown. Although Weakly Interacting Massive Particles (WIMPs) are among the
best-motivated thermally produced DM candidates, they have not been detected so
C. Cosme ()
Ottawa-Carleton Institute for Physics, Carleton University, Ottawa, ON, Canada
e-mail: ccosme@physics.carleton.ca
© Springer Nature Switzerland AG 2021
M. B. Paranjape et al. (eds.), Quantum Theory and Symmetries, CRM Series in
Mathematical Physics, https://doi.org/10.1007/978-3-030-55777-5_38
417
Through the Higgs-Portal
Catarina Cosme
Abstract We introduce an oscillating scalar field coupled to the Higgs that can
account for all dark matter in the Universe. Due to an underlying scale invariance of
this model, the dark scalar only acquires mass after the electroweak phase transition.
We discuss the dynamics of this dark matter candidate, showing that it behaves like
dark radiation until the electroweak phase transition and like non-relativistic matter
afterwards. In the case of a negative coupling to the Higgs field, the scalar gets a
vacuum expectation value after the electroweak phase transition and may decay into
photons although being sufficiently long-lived to account for dark matter. We show
that, within this scenario, for a mass of 7 keV, the model can explain the observed
galactic and extra-galactic 3.5 keV X-ray line. Nevertheless, it will be very difficult
to probe this model in the laboratory in the near future. This proceedings paper is
based on Refs. Cosme et al. (J High Energy Phys 1805, 129, 2018; Phys Lett B 781,
639, 2018).
Keywords Dark matter · Scalar field · Higgs boson
1 Introduction
Dark matter (DM) is one of the greatest unsolved questions in Physics. This
invisible form of matter constitutes almost 27% of the Universe’s energy density
content and is required to explain its structure on large scales, the anisotropies
in the Cosmic Microwave Background (CMB), and the galaxy rotation curves.
Despite a large number of candidates that arise in theories beyond the Standard
Model of Particle Physics (SM), the origin and the constitution of DM remain
unknown. Although Weakly Interacting Massive Particles (WIMPs) are among the
best-motivated thermally produced DM candidates, they have not been detected so
C. Cosme ()
Ottawa-Carleton Institute for Physics, Carleton University, Ottawa, ON, Canada
e-mail: ccosme@physics.carleton.ca
© Springer Nature Switzerland AG 2021
M. B. Paranjape et al. (eds.), Quantum Theory and Symmetries, CRM Series in
Mathematical Physics, https://doi.org/10.1007/978-3-030-55777-5_38
417