DESY/Hamburg U. String Theory Seminar

Four Graviton Scattering Amplitudes at Two Loops

by Harald Ita (University of Freiburg)

Europe/Berlin
Online

Online

Description

We apply the unitarity method to obtain the analytic form of the two-loop four-graviton scattering amplitudes in Einstein gravity. The theory's S-matrix elements have been known to diverge in the ultraviolet at two-loop order which we confirm. To deal with the ultraviolet divergences we include counter terms quadratic and cubic in the Riemann curvature tensor and work in the effective field theory with additional coupling parameters. We show that four graviton scattering observables depend on fewer couplings than naively expected.

https://zoom.us/j/99321745504?pwd=NHFuWkRxL0trcGZxQTNrUHQxNFpZQT09