Inclusive prompt photon production in hadronic final states of e+e- annihilation.

Abstract

We provide complete analytic expressions for the inclusive prompt photon production cross section in hadronic final states of ${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{\ensuremath{-}}}$ annihilation reactions through one-loop order in quantum chromodynamics perturbation theory. Computed explicitly are direct photon production through first order in the electromagnetic strength ${\mathrm{\ensuremath{\alpha}}}_{\mathrm{em}}$ and the quark-to-photon and gluon-to-photon fragmentation contributions through first order in the strong coupling ${\mathrm{\ensuremath{\alpha}}}_{\mathit{s}}$. The full angular dependence of the cross sections is displayed, separated into transverse (1+${\mathrm{cos}}^{2}$${\mathrm{\ensuremath{\theta}}}_{\ensuremath{\gamma}}$) and longitudinal (${\mathrm{sin}}^{2}$${\mathrm{\ensuremath{\theta}}}_{\ensuremath{\gamma}}$) components, where ${\mathrm{\ensuremath{\theta}}}_{\ensuremath{\gamma}}$ specifies the direction of the photon with respect to the ${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{\ensuremath{-}}}$ collision axis. We discuss extraction of fragmentation functions from ${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{\ensuremath{-}}}$ data. \textcopyright{} 1996 The American Physical Society.