26-30 July 2021
Europe/Berlin timezone

Cosmic Axion Background: the QCD axion as a hot relic

27 Jul 2021, 16:20


Parallel session talk Cosmology T02: Cosmology


Alessio Notari


QCD Axions can be produced in various ways in the Early Universe by scatterings and decays from Standard Model particles, forming thus a Cosmic Axion Background that contributes to the abundance of relativistic relics (N_eff). We review in various setups how this is already constrained by present experiments and how it could be observed by future CMB experiments, in particular focusing on the coupling to quarks and leptons, the bounds on the DFSZ model, and also the connection with the Xenon1T excess.

Collaboration / Activity Theory

Primary author

Presentation Materials