Differential equations and dispersion relations for Feynman amplitudes. The two-loop massive sunrise and the kite integral

作者：Remiddi Ettore; Tancredi Lorenzo^*

来源：Nuclear Physics B, 2016, 907: 400-444.

DOI：10.1016/j.nuclphysb.2016.04.013

It is shown that the study of the imaginary part and of the corresponding dispersion relations of Feynman graph amplitudes within the differential equations method can provide a powerful tool for the solution of the equations, especially in the massive case.
The main features of the approach are illustrated by discussing the simple cases of the 1-loop self-mass and of a particular vertex amplitude, and then used for the evaluation of the two-loop massive sunrise and the QED kite graph (the problem studied by Sabry in 1962), up to first order in the (d - 4) expansion.

• 出版日期2016-6