D* Production in Deep Inelastic Scattering at HERA

Abstract

This paper presents measurements of D^{*\pm} production in deep inelastic scattering from collisions between 27.5 GeV positrons and 820 GeV protons. The data have been taken with the ZEUS detector at HERA. The decay channel $D^{\ast +}\to (D^0\to K^{-}\ddot{I}{€}^{+})\ddot{I}{€}^{+}$ (+ c.c.) has been used in the study. The $e^{+}p$ cross section for inclusive D^{*\pm} production with $5<Q^2<100Ge{V}^2$ and $y<0.7$ is 5.3 \pms 1.0 \pms 0.8 nb in the kinematic region {$1.3<p_T(D^{\ast \pm })<9.0$ GeV and $|\hat{I}\cdot (D^{\ast \pm })|<1.5$}. Differential cross sections as functions of p_T(D^{*\pm}), $\hat{I}\cdot (D^{\ast \pm }),W$ and $Q^2$ are compared with next-to-leading order QCD calculations based on the photon-gluon fusion production mechanism. After an extrapolation of the cross section to the full kinematic region in p_T(D^{*\pm}) and $\hat{I}\cdot$(D^{*\pm}), the charm contribution $F_2^{c\bar{c}}(x,Q^2)$ to the proton structure function is determined for Bjorken $x$ between 2 $\cdot$ 10${}^{-4}$ and 5 $\cdot$ 10${}^{-3}$.

17 pages including 4 figures