Speaker
Description
I will discuss the high-energy, small-angle limit of two-body classical gravitational scattering amplitudes, focusing on the tower of multi-H diagrams that govern the leading logarithmic behavior. First, I will show that the recently developed SCET forward-scattering framework for gravity is fully equivalent to the multi-Regge expansion of the classical amplitude, reproducing exactly the s-channel multi-H diagrams. I will then compute the single-H diagram at two loops and the double-H diagrams at four loops, matching onto the classical eikonal phase in the ultrarelativistic limit. Finally, using dispersion relations, we establish a novel link between the high-energy logarithmic terms in the real and imaginary parts of the eikonal phase at 5PM order.
