Measurement of D*(+/-) production and the charm contribution to F-2 in deep inelastic scattering at HERA

The production of \(D^{\ast \pm}\)(2010) mesons in deep inelastic scattering has been measured in the ZEUS detector at HERA using an integrated luminosity of 37 pb\(^{-1}\). The decay channels \(D^{\ast +}\rightarrow D^0 \pi^+ \) (+ c.c.), with \(D^0 \rightarrow K^- \pi^+\) or \(D^0 \rightarrow K^- \pi^- \pi^+ \pi^+\), have been used to identify the D mesons. The \(e^+p\) cross section for inclusive \(D^{\ast \pm}\) production with \(1 < Q^2 < 600\,\)GeV\(^2\) and \(0.02< y < 0.7\) is \(8.31 \pm 0.31 \mbox{(stat.)}^{+0.30}_{-0.50}\mbox{(syst.)}\) nb in the kinematic region \(1.5 < p_T(D^{\ast \pm}) < 15\) GeV and \(|\eta(D^{\ast \pm})| < 1.5\). Differential cross sections are consistent with a next-to-leading-order perturbative-QCD calculation when using charm-fragmentation models which take into account the interaction of the charm quark with the proton remnant. The observed cross section is extrapolated to the full kinematic region in \(p_T(D^{\ast \pm})\) and \(\eta(D^{\ast \pm})\) in order to determine the charm contribution, \(F_{2}^{c\bar c}(x,Q^2)\), to the proton structure function. The ratio \(F_{2}^{c\bar c}/F_{2}\) rises from \(\simeq\)10% at \(Q^2 \simeq\) 1.8 GeV\(^2\) to \(\simeq\)30% at \(Q^2 \simeq \)130 GeV\(^2\) for x values in the range \(10^{-4}\) to \(10^{-3}\).