Cosmological constraints and phenomenology of a beyondHorndeski model
Abstract
We study observational constraints on a specific dark energy model in the framework of GleyzesLangloisPiazzaVernizzi theories, which extends the Galileon ghost condensate (GGC) to the domain of beyond Horndeski theories. In this model, we show that the Planck cosmic microwave background (CMB) data, combined with datasets of baryon acoustic oscillations, supernovae type Ia, and redshiftspace distortions, give the tight upper bound α_{H}^{(0 )}≤O (10^{6}) on today's beyondHorndeski (BH) parameter α_{H}. This is mostly attributed to the shift of CMB acoustic peaks induced by the earlytime changes of cosmological background and perturbations arising from the dominance of α_{H} in the dark energy density. In comparison to the Λ cold dark matter (Λ CDM ) model, our BH model suppresses the largescale integratedSachsWolfe tail of CMB temperature anisotropies due to the existence of cubic Galileons, and it modifies the smallscale CMB power spectrum because of the different background evolution. We find that the BH model considered fits the data better than Λ CDM according to the χ^{2} statistics, yet the deviance information criterion (DIC) slightly favors the latter. Given the fact that our BH model with α_{H}=0 (i.e., the GGC model) is favored over Λ CDM even by the DIC, there are no particular signatures for the departure from Horndeski theories in current observations.
 Publication:

Physical Review D
 Pub Date:
 September 2019
 DOI:
 10.1103/PhysRevD.100.063509
 arXiv:
 arXiv:1905.11364
 Bibcode:
 2019PhRvD.100f3509P
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology
 EPrint:
 17 pages, 12 figures, accepted version by PRD