Evidence for dark matter interactions in cosmological precision data?

By Julien Lesgourgues, G. Marques-Tavares, M. Schmaltz. 2015

165 citations recorded by the source corpus.

We study a two-parameter extension of the cosmological standard model ΛCDM in which cold dark matter interacts with a new form of dark radiation. The two parameters correspond to the energy density in the dark radiation fluid ΔNfluid and the interaction strength between dark matter and dark radiation. The interactions give rise to a very weak ``dark matter drag'' which damps the growth of matter density perturbations throughout radiation domination, allowing to reconcile the tension between predictions of large scale structure from the CMB and direct measurements of σ8. We perform a precision fit to Planck CMB data, BAO, large scale structure, and direct measurements of the expansion rate of the universe today. Our model lowers the χ-squared relative to ΛCDM by about 12, corresponding to a preference for non-zero dark matter drag by more than 3σ. Particle physics models which naturally produce a dark matter drag of the required form include the recently proposed non-Abelian dark matter model in which the dark radiation corresponds to massless dark gluons.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/4787449733405110118199ca2ee4cfc0c0c1237d

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Nuclear and High Energy Physics

Citations in the corpus

Alleviating the H0 and σ8 anomalies with a decaying dark matter model (2019, background): “Many forms of Γ have been studied in the literature [29, 47–50].”
Evidence for a sublattice weak gravity conjecture (2016, background): “Dark matter coupled to nonabelian dark radiation can damp the matter power spectrum in a specific way [55–57] that has been argued to improve fits to observation by 3σ [56].”
CMB-S4 Science Case, Reference Design, and Project Plan (2019, background): “These possibilities may also play a role in explaining the discrepancies observed in the Hubble constant H0 measurements [160, 161, 162, 163, 164], the amplitude of fluctuations σ8 [165, 166, 167, 168], and clustering on small scales [169, 127].”
Implications of an extended dark energy cosmology with massive neutrinos for cosmological tensions (2018, background): “Interactions in the dark matter sector helps to address the S8 problem [20, 21, 54], but are in tension with Ly-α data [20, 55].”
A fresh look at linear cosmological constraints on a decaying Dark Matter component (2016, background): “Numerous alternative explanations are available in the literature: we can mention a possible interaction between dark matter and dark radiation [37] or in the dark energy sector [38], or adding sterile neutrinos with pseudoscalar self-interactions [39].”
Interacting dark sector and precision cosmology (2017, background): “In the 2015 results of [11], high values of H0 could be reached for models with a significant DR density.”
Gravitational probes of dark matter physics (2017, background): “mental cosmological parameters. Decaying dark matter can reduce the amplitude of matter uctuations with time, as well as change the expansion history of the Universe compared to the standard CDM case [504, 505, 506, 507, 508]. Hidden sector dark matter with a dark photon can also ameliorate these te”