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Ekta Chaubey

Publications and source records attributed to Ekta Chaubey.

23 records · Page 2Linked to original sources
arXiv2018

Analytic results for the planar double box integral relevant to top-pair production with a closed top loop

In this article we give the details on the analytic calculation of the master integrals for the planar double box integral relevant to top-pair production with a closed top loop. We show that these integrals can be computed systematically to all order in the dimensional regularisation parameter $\varepsilon$. This is done by transforming the system of differential equations into a form linear in $\varepsilon$, where the $\varepsilon^0$-part is a strictly lower triangular matrix. Explicit results in terms of iterated integrals are presented for the terms relevant to NNLO calculations.

hep-ph↗
arXiv2018

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

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.

hep-ph↗
arXiv2018

From elliptic curves to Feynman integrals

In this talk we discuss Feynman integrals which are related to elliptic curves. We show with the help of an explicit example that in the set of master integrals more than one elliptic curve may occur. The technique of maximal cuts is a useful tool to identify the elliptic curves. By a suitable transformation of the master integrals the system of differential equations for our example can be brought into a form linear in $\varepsilon$, where the $\varepsilon^0$-term is strictly lower-triangular. This system is easily solved in terms of iterated integrals.

hep-ph↗
arXiv2017

Simplifying differential equations for multi-scale Feynman integrals beyond multiple polylogarithms

In this paper we exploit factorisation properties of Picard-Fuchs operators to decouple differential equations for multi-scale Feynman integrals. The algorithm reduces the differential equations to blocks of the size of the order of the irreducible factors of the Picard-Fuchs operator. As a side product, our method can be used to easily convert the differential equations for Feynman integrals which evaluate to multiple polylogarithms to $\varepsilon$-form.

hep-ph↗