Applied Physics/Physics Colloquium: Benjamin Safdi - " The Search for Axion Dark Matter"

Abstract: Axions are some of the best-motivated beyond the Standard Model particle candidates at present. These ultralight particles may account for the cosmological dark matter and explain other outstanding problems in nature, such as the strong-CP problem; they also are now known to emerge generically in string theory. Axions are expected to couple ultra-weakly with ordinary matter, which complicates their detection. However, thanks to recent theoretical, experimental, and observational progress these particles may be discovered or ruled out within the near future. I will review some of the recent ideas that may soon play a role in axion discovery, including theoretical predictions for the axion mass and novel observational signatures of axions that emerge in extreme astrophysical environments such as supernovae.

Benjamin Safdi received his undergraduate degree from the University of Colorado at Boulder, a Master of Advanced Study from Cambridge University, as a Churchill Scholar, and his PhD from Princeton University in 2014. He was then a Pappalardo Fellow at the Massachusetts Institute of Technology until 2017, when he started as an assistant professor at the University of Michigan, Ann Arbor. Dr. Safdi moved to LBNL in 2020 and then to UC Berkeley in 2021. He received the Department of Energy Early Career Award in 2018, the IUPAP C11 Young Scientist Prize in Particles and Fields in 2020, the Sloan Research Fellowship in 2023, and the New Horizons in Physics Prize in 2026 for his contributions to the search for the axion.