Relating diagrammatic expansion with conformal correlator expansion

Abstract

In this note we study the possible connection between functions appearing in diagrammatic expansion and the conformal correlator expansion. To study the connection we propose a generating function which can be expanded to construct a basis. This basis can be utilized to expand, I) the four point function of scalars near the Wilson-Fisher fixed point in $d=4-\epsilon$ as in \cite{Alday:2017zzv} and II) integrals for loop diagrams for massless $\phi^4$ theory in position space in four dimensions. This suggests that a linear combination of one expansion can be recast in terms of a linear combination of the other. As a by-product, we also derive the Mellin space representation for the twist-2 higher spin conformal blocks. We also discuss the higher derivative contact terms in the present scenario.