Speaker
Description
In this talk, we present a framework for computing the maximally transcendental part of planar QCD scattering amplitudes. By analyzing the maximal-weight projection of amplitudes at the integrand level, we relate these contributions to prescriptive unitarity integrals and uncover a novel analytic structure: the rational prefactors multiplying functions of maximal transcendental weight coincide with the four-dimensional leading singularities of the theory. This observation implies that the pre-factors admit a complete classification and can be systematically computed using on-shell methods. As an application, we determine the two-loop pre-factors for planar MHV gluon amplitudes at arbitrary multiplicity. Combining these results with the known six-point function space, we bootstrap the symbol of the two-loop six-gluon MHV amplitude in QCD in the planar limit.
