Soft-gluon Factorization at Two-loop in Full Color

Monday, 2 November 2020 at 11:15, in Y36 K08 - Campus Irchel

The factorization properties of gauge-theory amplitudes in the infrared kinematic regime is of great theoretical interests. Understanding the universal factorization behaviors at fixed-order is central to the subjects of IR subtraction in phase-space integrals, resummation of large logarithms in physical observables and bootstrapping the complete scattering amplitudes. Recently we computed the two-loop soft gluon emission factor which captures the leading-power behavior of multi-point scattering amplitude with a single soft gluon in the final state. At two loop it exhibits a new “tripole” structure due to soft gluon coupling to three hard partons. The full tripole contribution is linear combination of single-valued harmonic polylogarithms, and a continuous function in the physical scattering regime. The tri-pole function encodes valuable information about the analytic properties of the full amplitudes, as well as potential factorisation violating effect in the space-like collinear limit.