On string axions and the dark universe

by Nicole Righi (SNS)

Thursday 16 Apr 2026, 15:00 → 17:00 Europe/Rome

room 248 Ed. C Pisa

String axions have been proposed as candidates for solving a number of puzzles in cosmology. In this talk, I will focus on ultralight axions as dark matter. After a review on why and how string axions can occur in our universe, I will provide a string theoretical explanation of dark matter as composed by axions coming from superstring theory on Calabi-Yau manifolds. Based on the latest bounds, I will show how likely it is for dark matter to be composed of such particles and in which abundance, and I will provide predictions on the preferred ranges of masses and decay constants. On the contrary, requiring the axions to lie in a particular range of the parameter space imposes constraints on the UV theory. I will focus both on the role of moduli stabilization and on the statistical properties of the string landscape. In the end, I will present some interesting future directions in axion theory.