HQET vertex diagram: $\epsilon$ expansion

Abstract

Differential equations for the one-loop HQET vertex diagram with arbitrary self-energy insertions and arbitrary residual energies are reduced to the $\epsilon$ form and used to obtain the $\epsilon$ expansion in terms of Goncharov polylogarithms.

Comments: 7 pages; v2: ref [13] added, 2 typos fixed; v3: 1 ref added, 1 typo fixed; v4: 2 refs added