Thursday, December 27, 2012

1212.6228 (Arthur E. Lipstein et al.)

From the holomorphic Wilson loop to `d log' loop-integrands for
super-Yang-Mills amplitudes
   [PDF]

Arthur E. Lipstein, Lionel Mason
The S-matrix for planar N = 4 super Yang-Mills theory can be computed as the correlation function for a holomorphic polygonal Wilson loop in twistor space. In an axial gauge, this leads to the construction of the all-loop integrand via MHV diagrams in twistor space. We show that at MHV, this formulation leads directly to expressions for loop integrands in d log form; i.e., the integrand is a product of exterior derivatives of logarithms of rational functions. For higher MHV degree, it is in d log form multiplied by delta functions. The parameters appearing in the d log form arise geometrically as the coordinates of insertion points of propagators on the holomorphic Wilson loop or on MHV vertices. We discuss a number of examples at one and two loops and give a preliminary discussion of the evaluation of the 1-loop MHV amplitude.
View original: http://arxiv.org/abs/1212.6228

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