Abstract
We compute the four-loop n f contribution proportional to the quartic Casimir of the QCD cusp anomalous dimension as an expansion for small cusp angle ϕ. This piece is gauge invariant, violates Casimir scaling, and first appears at four loops. It requires the evaluation of genuine non-planar four-loop Feynman integrals. We present results up to \( \mathcal{O}\left({\phi}^4\right) \). One motivation for our calculation is to probe a recent conjecture on the all-order structure of the cusp anomalous dimension. As a byproduct we obtain the four-loop HQET wave function anomalous dimension for this color structure.
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ArXiv ePrint: 1708.01221
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HQET Master Integrals. The file contains the HQET master integrals according to the definition in eq.(2.14) and their results written as a list of replacement rules in Mathematica format. (TXT 24 kb)
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Grozin, A., Henn, J. & Stahlhofen, M. On the Casimir scaling violation in the cusp anomalous dimension at small angle. J. High Energ. Phys. 2017, 52 (2017). https://doi.org/10.1007/JHEP10(2017)052
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DOI: https://doi.org/10.1007/JHEP10(2017)052
Keywords
- Effective Field Theories
- Heavy Quark Physics
- Perturbative QCD
- Resummation