A First Look at Bootstrapping QCD Amplitudes

Qinglin Yang (MPP, Munich)

Mar 19. 2026, 10:30 — 11:30

In this talk, we present a bootstrap construction of planar two-loop six-gluon scattering amplitudes in massless QCD, focusing on their maximally transcendental parts. The procedure proceeds in two steps. First, we identify a complete, conformally invariant set of prefactors using on-shell diagram techniques. Combining these results with the recently constructed space of two-loop planar hexagon functions, we then find that the relevant helicity amplitudes are uniquely determined by imposing the correct physical limits. This provides the first detailed description of two-loop six-gluon amplitudes at the symbol level. We also identify a tightly constrained function alphabet for six-point MHV processes. Finally, we discuss deeper connections between these bootstrapped results, the prescriptive unitarity approach, and the principle of maximal transcendentality. Our results suggest a deeper organizing principle for QCD amplitudes, similar to that observed in maximally supersymmetric Yang–Mills theory.

Further Information
Venue:
ESI Boltzmann Lecture Hall
Associated Event:
Amplitudes and Algebraic Geometry (Thematic Programme)
Organizer(s):
Daniele Agostini (U Tübingen)
Lara Bossinger (UNAM, Oaxaca)
Ruth Britto (Trinity College, Dublin)
Johannes Henn (MPP, Munich)
Jianrong Li (U of Vienna)
Anna-Laura Sattelberger (MPI MIS, Leipzig)
Oliver Schlotterer (Uppsala U)