Unveiling dark fifth forces with linear cosmology
- ,
- ,
- ,
- Ennio Salvioni()
- CERN and
- Padua U. and
- INFN, Padua
54 pages
Published in:
- JCAP 10 (2022) 074,
- JCAP 10 (2022) 074
- Published: Oct 24, 2022
e-Print:
- 2204.08484 [astro-ph.CO]
Report number:
- CERN-TH-2022-066
Citations per year
Abstract: (IOP)
We initiate the exploration of the cosmology of dark fifth forces: new forces acting
solely on Dark Matter. We focus on long range interactions which lead to an effective violation of
the Equivalence Principle on cosmological scales today. At the microscopic level, the dark fifth
force can be realized by a light scalar with mass smaller than the Hubble constant today
(≲ 10 eV) coupled to Dark Matter. We study the behavior of the background
cosmology and linear perturbations in such a Universe. At the background level, the new force
modifies the evolution of the Dark Matter energy density and thus the Hubble flow. At linear
order, it modifies the growth of matter perturbations and generates relative density and velocity
perturbations between Dark Matter and baryons that grow over time. We derive constraints from
current CMB and BAO data, bounding the strength of the dark fifth force to be less than a percent
of gravity. These are the strongest constraints to date. We present potential implications of this
scenario for the Hubble tension and discuss how our results are modified if the light scalar
mediator accounts for the observed density of the Dark Energy. Finally, we comment on the
interplay between our constraints and searches for violations of the Equivalence Principle in the
visible sector.Note:
- 54 pages, 15 figures. v2: revision of Section 6, now including atomic clock constraints; added Table 1 summarizing the main results; extended discussion of BAO; added several references. Matches version to appear in JCAP. v3: fixed some incorrect equations, all results and figures unaffected. Updated with latest experimental constraints from MICROSCOPE and atomic clocks
- baryon acoustic oscillations
- cosmological perturbation theory
- dark matter theory
- particle physics - cosmology connection
- equivalence principle: violation
- dark energy: density
- matter: perturbation
- interaction: long-range
- velocity: perturbation
- perturbation: linear
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Figures(26)
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