Four-loop photon quark form factor and cusp anomalous dimension in the large-$N_c$ limit of QCD

Abstract

We compute the four-loop QCD corrections to the massless quark-anti-quark-photon form factor $F_q$ in the large-$N_c$ limit. From the pole part we extract analytic expressions for the corresponding cusp and collinear anomalous dimensions.

Comments: 12 pages; v2: author added, note added, references added, minor modifications