Robust cosmological constraints on axion-like particles

Understand

Axion-like particles with masses in the keV-GeV range have a profound impact on the cosmological evolution of our Universe, in particular on the abundance of light elements produced during Big Bang Nucleosynthesis.

• The resulting limits are complementary to searches in the laboratory and provide valuable additional information regarding the validity of a given point in parameter space.
• A potential drawback is that altering the cosmological history may potentially weaken or even fully invalidate these bounds.
• The main objective of this article is therefore to evaluate the robustness of cosmological constraints on axion-like particles in the keV-GeV region, allowing for various additional effects which may weaken the bounds of the standard scenario.