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arXiv · 1103.1869

Basics of Generalized Unitarity

Zvi Bern·Yu-tin Huang
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Abstract

We review generalized unitarity as a means for obtaining loop amplitudes from on-shell tree amplitudes. The method is generally applicable to both supersymmetric and non-supersymmetric amplitudes, including non-planar contributions. Here we focus mainly on N=4 Yang-Mills theory, in the context of on-shell superspaces. Given the need for regularization at loop level, we also review a six-dimensional helicity-based superspace formalism and its application to dimensional and massive regularizations. An important feature of the unitarity method is that it offers a means for carrying over any identified tree-level property of on-shell amplitudes to loop level, though sometimes in a modified form. We illustrate this with examples of dual conformal symmetry and a recently discovered duality between color and kinematics.

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Zvi Bern, Yu-tin Huang. 2011-03-09. Basics of Generalized Unitarity. https://doi.org/10.1088/1751-8113%2F44%2F45%2F454003

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