The inclusive measurement of charm production in deep inelastic scattering with the ZEUS detector at HERA is presented in this thesis. In a first step, the existing algorithm from the inclusive secondary vertexing analysis was generalised using the signed impact parameter of jet-associated tracks to extract the heavy quark content of the data sample. In a second step, the algorithm was extended by using the decay vertex in events containing a well-reconstructed secondary vertex, the impact parameter in events not containing a secondary vertex, and a combination of vertexing and tracking information in all other events. The combined algorithm has reduced the relative statistical and systematic uncertainties on the measured double differential cross sections in Q2 and x. The relative statistical error has been reduced by 40 % on average, whilst the systematic uncertainty decreased due to an improved tracking efficiency. In order to extend the kinematic region and further reduce the uncertainty on the extrapolation of the charm contribution, F2cc, to the structure function of the proton the cut on the transverse jet energy has been relaxed from ET > 4.2 GeV to ET > 2.5 GeV. An extrapolation of the visible cross sections to the full kinematic phase space was performed allowing an extraction of F2cc to be made for a well-defined set of points in the x and Q2 plane. A comparison with previous results shows that lowering the cut on the transverse energy has particularly reduced the uncertainty on the extrapolation in the low Q2 and low x region. The present analysis is well described by next-to-leading order QCD predictions generated with the HVQDIS program. At present it is the most precise measurement of charm production cross sections with the ZEUS detector, and will have a significant impact on future combinations of ZEUS and H1 data.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:594327 |
| Date | January 2013 |
| Creators | Mujkic, K. |
| Publisher | University College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://discovery.ucl.ac.uk/1402953/ |
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