One-loop pentagon integral with one offshell leg in $d$ dimensions from differential equations in $\epsilon$-form

Abstract

We apply differential equations technique to the calculation of the one-loop massless diagram with one offshell legs. Using reduction to $\epsilon$-form, we managed to obtain a simple one-fold integral representation exact in space-time dimensionality. Expansion of the obtained result in $\epsilon$ and analytical continuation to physical region are discussed.