Nicole Righi (KCL), String axions as ultralight dark matter and beyond

Tuesday 26 Mar 2024, 11:15 → 12:15 Europe/Stockholm

Albano 3: 6228 - Mega (22 seats) (Albano Building 3)

String axions have been proposed as candidates for solving a number of puzzles in cosmology. In this talk, I will focus on ultralight axions and dark matter. After a review on how string axions occur in our universe, I will provide a string theoretical explanation of fuzzy dark matter as composed by axions coming from type IIB string 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 interesting constraints on the UV theory.