Abstract
We present an analytic computation of the gluon-initiated contribution to diphoton plus jet production at hadron colliders up to two loops in QCD. We reconstruct the analytic form of the finite remainders from numerical evaluations over finite fields including all colour contributions. Compact expressions are found using the pentagon function basis. We provide a fast and stable implementation for the colour- and helicity-summed interference between the one-loop and two-loop finite remainders in C++ as part of the NJet library.
Highlights
We present an analytic computation of the gluon-initiated contribution to diphoton plus jet production at hadron colliders up to two loops in QCD
The analytic computation of the scattering amplitudes in a form suitable for phenomenological applications requires a number of major technical bottlenecks to be overcome
We approach the problem through a direct analytic reconstruction of the amplitudes at the level of the pentagon functions performing all intermediate steps numerically over finite fields
Summary
We consider the production of a pair of photons in association with a gluon from gluon fusion, g(−p1) + g(−p2) → g(p3) + γ(p4) + γ(p5) ,. The scattering of gluons and photons is a one-loop process at leading order. The subleading-colour two-loop amplitudes contain only planar integrals, while the leading colour contains all of the four independent families shown in figure 1. This pattern is the opposite to that of the quark-initiated channels computed in refs. Diagrams (d)–(e), which contribute to the subleading colour, remain planar (allowing for permutations of the external momenta). The one- and two-loop finite remainders are given in terms of the bare amplitudes by [76,77,78,79,80],. The β0 term in the definition of the two-loop finite remainder accounts for the strong coupling renormalisation.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
