Abelian InstantonsConfirmed

by John Terning (University of California, Davis)

Friday Feb 28, 2025, 1:00 p.m. → 2:30 p.m. America/Toronto

PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)

It is usually assumed that 4D instantons can only arise in non-Abelian theories. One can, however, explicitly construct instantons for QED in the background of a Dirac monopole. This is the low-energy effective field theory for fermions interacting with a 't Hooft-Polyakov monopole. This theory posesses both a topological instanton number and 't Hooft zero modes. I will show how such instantons provide the underlying mechanism for the Callan-Rubakov process: monopole-catalyzed baryon decay with a cross section that saturates the unitarity bound.