Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The full four-loop cusp anomalous dimension in $\mathcal{N}=4$ super
  Yang-Mills and QCD   We present the complete formula for the cusp anomalous dimension at four
loops in QCD and in maximally supersymmetric Yang-Mills. In the latter theory
it is given by \begin{equation}
  {\Gamma}^{\rm}_{\rm cusp}\Big|_{\alpha_s^4} = -\left( \frac{\alpha_s
N}{\pi}\right)^4 \left[ \frac{73 \pi^6}{20160} + \frac{ \zeta_{3}^2}{8} +
\frac{1}{N^2}
  \left( \frac{31\pi^6}{5040} + \frac{9 \zeta_3^2}{4} \right) \right]
\,.\nonumber \end{equation} Our approach is based on computing the correlation
function of a rectangular light-like Wilson loop with a Lagrangian insertion,
normalized by the expectation value of the Wilson loop. In maximally
supersymmetric Yang-Mills theory, this ratio is a finite function of a
cross-ratio and the coupling constant. We compute it to three loops, including
the full colour dependence. Integrating over the position of the Lagrangian
insertion gives the four-loop Wilson loop. We extract its leading divergence,
which determines the four-loop cusp anomalous dimension. Finally, we employ a
supersymmetric decomposition to derive the last missing ingredient in the
corresponding QCD result.

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The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
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The categories of this paper are: atom-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-th
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The categories of this paper are: physics
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The categories of this paper are: dg-ga
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The categories of this paper are: funct-an
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The categories of this paper are: chem-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: eess
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The categories of this paper are: chao-dyn
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-alg
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The categories of this paper are: nlin