Two Stories About Axion Physics
Matthew Reece (Harvard U.)

This talk will take the form of two mini-talks, which are loosely related in that both involve axion (or ALP) fields. First, I will discuss challenges when fitting the muon g-2 anomaly with axion-like fields in an EFT setting. I will argue that new particles are required near the weak scale to UV complete these models, and these are subject to experimental constraints and can also affect the muon g-2 directly. This is based on arXiv:2104.03267 with Manuel Buen-Abad, JiJi Fan, and Chen Sun. Second, I will discuss how axions interacting with abelian gauge fields acquire a potential through a nonperturbative, semiclassical effect involving loops of monopoles and dyons. This is an application of the Witten effect. This is based on arXiv:2105.09950 with JiJi Fan, Katie Fraser, and John Stout.