Screening the matter–dilaton interaction without spoiling Hubble-tension alleviation

Develop a screening mechanism for matter–dilaton interactions within the yoga natural relaxation framework that suppresses late-Universe dilaton–matter couplings sufficiently, while preserving the recombination-era effects that help alleviate the Hubble tension, and determine how such screening feeds into axion couplings and the matter-induced axion potential.

Background

In yoga models the dilaton couples to matter with Brans–Dicke–like strength, creating potential conflicts with solar-system tests of gravity. The authors note that screening could resolve this but emphasize that it must not erase the time-variation effects that improve the Hubble tension fit in their framework.

They explicitly identify this as an unresolved issue and indicate that a complete picture must track how any such screening mechanism impacts axion couplings and the matter-induced axion potential that underpins their cosmological conclusions.