The QCD Axion Mass in String TheoryConfirmed

by Benjamin Safdi (University of California, Berkeley)

Tuesday Apr 14, 2026, 1:00 PM → 2:30 PM America/Toronto

PI/3-394 - Skyroom (Perimeter Institute for Theoretical Physics)

Axions, grand unification, and string theory are each compelling extensions of the Standard Model. I will show that combining these frameworks imposes strong constraints on the QCD axion mass. Using unitarity arguments and explicit string compactifications - such as those from the Kreuzer-Skarke (KS) type IIB ensemble - I will discuss why the axion mass is favored to lie within the range 1e-11 eV < m_a < 1e-8 eV.