2020 Impact factor 4.590
Particles and Fields
Eur. Phys. J. C 12, 35-52
DOI 10.1007/s100529900244

Measurement of $D^{\ast \pm}$ production and the charm contribution to F2 in deep inelastic scattering at HERA

The ZEUS Collaboration

J. Breitweg - et al.

Argonne National Laboratory, Argonne, IL, USA

Received: 30 July 1999 / Published online: 3 November 1999

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 37pb-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 $1<Q^2<600\,$GeV2 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 $\vert\eta(D^{\ast \pm})\vert < 1.5$. 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 $Q^2 \simeq$ 1.8GeV2to $\simeq$30% at $Q^2 \simeq$130GeV2 for x values in the range 10-4 to 10-3.

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