Takemichi Okui, Florida State University

"Soft collinear effective theory for gravity"

Abstract: I will discuss how to construct a Soft Collinear Effective Theory (SCET) for gravity at the leading and next-to-leading powers from the ground up. You will see that the effective lagrangian is highly constrained by effectively multiple copies of diffeomorphism invariance that are inevitably present in gravity SCET due to mode separation, an essential ingredient of any SCET. The soft graviton theorem and decoupling of collinear gravitons at the leading power will be manifest from the outset in the effective symmetries of the theory. At the next-to-leading power, the gravity SCET will reveal some simple structures of amplitudes that are completely obscure in Feynman diagrams of the full theory, which can greatly simplify calculations.