Speaker
Luigi Tizzano
(CERN)
Description
Abstract
In this talk, I will explain how leading soft photon theorems in QED can be understood from the perspective of generalized global symmetries. Using HQET and SCET, the soft sector is described by Wilson lines for massive and massless charged particles, making an emergent electric 1-form symmetry manifest. I will then show that this symmetry enhances to an infinite-dimensional algebra of charges. The corresponding Ward identity reproduces Weinberg’s soft photon theorem, making contact with the asymptotic symmetry interpretation of soft theorems. Finally, I will discuss extensions of this perspective to inclusive observables.