Topical Seminar: Strong cosmological bounds on ALPs from cosmic strings

por Riccardo Impavido (Università di Ferrara and INFN Ferrara )

lunes 2 mar. 2026 12:00 → 13:00 Europe/Madrid

Primera-1-1-1 - Paterna. Seminario (IFIC)

In this seminar I will focus on axion-like particles (ALPs) produced by a network of topological defects (cosmic strings). Such ALPs enjoy a very peculiar quasi scale-invariant distribution function spread across many orders of magnitude in momentum, allowing them to free-stream and thus to be constrained by cosmological microwave background (CMB) probes, most importantly CMB lensing. The work provides the most stringent bound on ALPs abundance in the mass window 10^-20- 10^-16 eV, where we claim they cannot be more than 10 per cent of Dark Matter.
If time permits I will also briefly touch upon two works, one on a formal result in inflationary cosmology that reaches beyond perturbation theory (2507.17593) and the other on a phenomenological investigation on the chemical potential of cosmological neutrinos.