Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the structure of scattering amplitudes in N=4 super Yang-Mills and
  N=8 supergravity   Exploiting singularities in Feynman integrals to get information about
scattering amplitudes has been particularly useful at one-loop in theories
where no triangles or bubbles appear. At higher loops the integrals possess
subtle singularities. In this paper we give these singularities a physical
interpretation and show how they turn tedious computations into purely
pictorial manipulations. We illustrate our methods with various examples from
the computation of four-particle amplitudes in N=4 super Yang-Mills and N=8
supergravity. Along the way we find clues towards an understanding i) of the
rung-rule as a consequence of infra-red singularities, ii) of the non rung-rule
integrals included in the basis as corrections to the rung-rule and iii) of the
coefficients - including signs - of these two types of contribution. The role
of corrections is to cancel unphysical singularities generically present in
rung-rule integrals. A further byproduct, coming from the fact such unphysical
singularities are located where conformal cross-ratios become unity, is the
possibility of understanding the dual conformal invariance ansatz for
constructing the basis of four-particle amplitudes in N=4 super Yang-Mills.

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The categories of this paper are: quant-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: physics
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The categories of this paper are: adap-org
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The categories of this paper are: chao-dyn
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The categories of this paper are: atom-ph
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The categories of this paper are: q-fin
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The categories of this paper are: q-alg
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The categories of this paper are: cond-mat
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The categories of this paper are: ao-sci
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The categories of this paper are: q-bio
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The categories of this paper are: solv-int
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The categories of this paper are: econ
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The categories of this paper are: gr-qc
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The categories of this paper are: bayes-an
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The categories of this paper are: stat