A Minimal Axio-dilaton Dark Sector

November 7, 2024
12:00pm to 1:00pm

IFT Seminar Room/Red Room

Specialist level
Speaker: 
Bruno Valeixo Bento
Institution: 
IFT UAM-CSIC
Location&Place: 

IFT Seminar Room/Red Room

Abstract: 

After the usual paper discussion, Bruno Valeixo Bento will give a talk on the paper "A Minimal Axio-dilaton Dark Sector" (2410.11099).

"In scalar-tensor theories it is the two-derivative sigma-model interactions that like to compete at low energies with the two-derivative interactions of General Relativity (GR)  at least once the dangerous zero-derivative terms of the scalar potential are suppressed (such as by a shift symmetry). But nontrivial two-derivative interactions require at least two scalars to exist and so never arise in the single-scalar models most commonly explored. Axio-dilaton models provide a well-motivated minimal class of models for which these self-interactions can be explored. We review this class of models and investigate whether these minimal two fields can suffice to describe both Dark Matter and Dark Energy. We find that they can  the axion is the Dark Matter and the dilaton is the Dark Energy  and that they robustly predict several new phenomena for the CMB and structure formation that can be sought in observations. These include specific types of Dark Energy evolution and small space- and time-dependent changes to particle masses post-recombination that alter the Integrated Sachs-Wolfe effect, cause small changes to structure growth and more."