Gluonic Three Jet Production at Next to Leading Order

I report results from a next-to-leading order event generator of purely gluonic jet production. This calculation, is the first step in the construction of a full next-to-leading order calculation of three jet production at hadron colliders.Comment: 4 pages, 2 figures, LaTeX, uses sprocl.sty and epsf.st

The Two-Loop Infrared Structure of Amplitudes with Mixed Gauge Groups

The infrared structure of (multi-loop) scattering amplitudes is determined entirely by the identities of the external particles participating in the scattering. The two-loop infrared structure of pure \qcd\ amplitudes has been known for some time. By computing the two-loop amplitudes for $\bar{f}\,f\longrightarrow X$ and $\bar{f}\,f\longrightarrow V_1\,V_2$ scattering in an $SU(N)\times SU(M)\times U(1)$ gauge theory, I determine the anomalous dimensions which govern the infrared structure for any massless two-loop amplitude.Comment: 12 pages, 4 figures. arXiv admin note: text overlap with arXiv:1205.401

Techniques for NNLO Higgs production in the Standard Model and the MSSM

New techniques developed in connection with the NNLO corrections to the Higgs production rate at hadron colliders and some recent applications are reviewed.Comment: 4 pages, LaTeX, 4 ps-files included. Talk presented at the XXXVIIIth Rencontres de Moriond, QCD and High Energy Hadronic Interactions, Les Arcs, France, March 22-29, 200

The Four Dimensional Helicity Scheme Beyond One Loop

I describe a procedure by which one can transform scattering amplitudes computed in the four dimensional helicity scheme into properly renormalized amplitudes in the 't Hooft-Veltman scheme. I describe a new renormalization program, based upon that of the dimensional reduction scheme and explain how to remove both finite and infrared-singular contributions of the evanescent degrees of freedom to the scattering amplitude.Comment: 20 page

Regularization Schemes and Higher Order Corrections

I apply commonly used regularization schemes to a multi-loop calculation to examine the properties of the schemes at higher orders. I find complete consistency between the conventional dimensional regularization scheme and dimensional reduction, but I find that the four dimensional helicity scheme produces incorrect results at next-to-next-to-leading order and singular results at next-to-next-to-next-to-leading order. It is not, therefore, a unitary regularization scheme.Comment: References added and typographical errors correcte