Heavy quark coefficient functions at asymptotic values $Q^2 \gg m^2$

M. Buza; Y. Matiounine; J. Smith; R. Migneron; W. L. van Neerven

Paper

Heavy quark coefficient functions at asymptotic values $Q^2 \gg m^2$

Abstract

In this paper we present the analytic form of the heavy-quark coefficient functions for deep-inelastic lepton-hadron scattering in the kinematical regime

. Here

and

stand for the masses squared of the virtual photon and heavy quark respectively. The calculations have been performed up to next-to-leading order in the strong coupling constant

using operator product expansion techniques. Apart from a check on earlier calculations, which however are only accessible via large computer programs, the asymptotic forms of the coefficient functions are useful for charm production at HERA when the condition

is satisfied. Furthermore the analytical expressions can also be used when one applies the variable heavy flavour scheme up to next-to-leading order in