Attracted to de Sitter II: cosmology of the shift-symmetric Horndeski models

Understand

Horndeski models with a de Sitter critical point for any kind of material content may provide a mechanism to alleviate the cosmological constant problem.

• Moreover, they could allow us to understand the current accelerated expansion of the universe as the result of the dynamical approach to the critical point when it is an attractor.
• We show that this critical point is indeed an attractor for the shift- symmetric subfamily of models with these characteristics.
• We study the cosmological scenario that results when considering radiation and matter content, and conclude that their background dynamics is compatible with the latest observational data.