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arXiv · 1804.11144

The planar double box integral for top pair production with a closed top loop to all orders in the dimensional regularisation parameter

Luise Adams·Ekta Chaubey·Stefan Weinzierl
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Abstract

We compute systematically for the planar double box Feynman integral relevant to top pair production with a closed top loop the Laurent expansion in the dimensional regularisation parameter $\varepsilon$. This is done by transforming the system of differential equations for this integral and all its sub-topologies to a form linear in $\varepsilon$, where the $\varepsilon^0$-part is strictly lower triangular. This system is easily solved order by order in the dimensional regularisation parameter $\varepsilon$. This is an example of an elliptic multi-scale integral involving several elliptic sub-topologies. Our methods are applicable to similar problems.

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Luise Adams, Ekta Chaubey, Stefan Weinzierl. 2018-09-11. The planar double box integral for top pair production with a closed top loop to all orders in the dimensional regularisation parameter. https://doi.org/10.1103/physrevlett.121.142001

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