Charm Production in Deep-Inelastic $e\gamma$ Scattering To Next-To-Leading Order in QCD

Abstract

We discuss the calculation of $F_2^{\gamma }(\mathrm{charm})$ to next-to-leading order (NLO) in QCD, including contributions from both hadronlike and pointlike photons. We show that the former dominates strongly below $x\simeq 0.01$, and the latter above this value. This fact makes $F_2^{\gamma }(\mathrm{charm})$ for $x\ge 0.01$ calculable, whereas for $x\le 0.01$ it serves to constrain the small-$x$ gluon density in the photon. Both ranges in $x$ are accessible at LEP2. Theoretical uncertainties are well under control. We present rates for single-tag events for the process for $e^{+}{e}^{-}\to e^{+}{e}^{-}cX$ for LEP2. Although these event rates are small, we believe a measurement of $F_2^{\gamma }(\mathrm{charm})$ is feasible.

Comments: 7 pages Latex, with 2 eps figs., uuencoded