$O({\alpha }_S)$ Corrections to the Photon Structure Functions $F_2^{\gamma }(x,Q^2)$ and $F_L^{\gamma }(x,Q^2)$

Abstract

We examine the QCD corrections to the structure functions $F_2^{\gamma }(x,Q^2)$ and $F_L^{\gamma }(x,Q^2)$ for a real photon target. The pointlike photon contributions from light and heavy quarks are computed through $O(\alpha {\alpha }_S)$. A parameterization of the hadronic (resolved) photon contribution is also included and a comparison is made with the present experimental data. We find that while the pointlike contributions are large for $F_2^{\gamma }(x,Q^2)$, they are the dominant part of $F_L^{\gamma }(x,Q^2)$. For $Q^2>50$ $(\mathrm{GeV}/c{)}^2$ the charm component is as least as large as the light quark component.

Comments: Latex 22 pages (16 figures available upon request), ITP-SB-93-1, FERMILAB-Pub-93/033-T