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@PHDTHESIS{Zenaiev:208394,
      author       = {Zenaiev, Oleksandr},
      title        = {{C}harm {P}roduction and {QCD} {A}nalysis at {HERA} and
                      {LHC}},
      issn         = {1435-8085},
      school       = {Universität Hamburg},
      type         = {Dr.},
      address      = {Hamburg},
      publisher    = {Verlag Deutsches Elektronen-Synchrotron},
      reportid     = {PUBDB-2015-01688, DESY-THESIS-2015-012},
      series       = {DESY-THESIS},
      pages        = {355},
      year         = {2015},
      note         = {Universität Hamburg, Diss., 2015},
      abstract     = {In this thesis the study of charm production in $\ep$ and
                      $\pp$ collisions is presented. The heavy-quark masses
                      provide a hard scale, allowing the application of
                      perturbative $QCD.\newlineA$ measurement of $D^{+}$-meson
                      production in deep inelastic scattering with the ZEUS
                      detector at HERA is presented. The analysis was performed
                      using a data sample with an integrated luminosity of $354$
                      $\text{pb}^{-1}$. Differential cross sections were measured
                      as a function of virtuality $Q^2$, inelasticity $y$,
                      transverse momentum and pseudorapidity of the $D^{+}$
                      mesons. Lifetime information was used to reduce the
                      combinatorial background significantly.
                      Next-to-leading-order QCD predictions in the
                      fixed-flavour-number scheme were compared to the
                      data.\newlineThis measurement was combined with other H1 and
                      ZEUS measurements of charm production. The combination was
                      performed at inclusive level for the reduced charm cross
                      sections, which were obtained from the measured visible
                      cross sections, extrapolated to the full phase space using
                      the shape of the theoretical predictions in the
                      fixed-flavour-number scheme. The combination method accounts
                      for the correlations of the systematic uncertainties among
                      the different datasets, thus allowing cross calibration of
                      different measurements. The combined charm data were
                      compared to QCD predictions in various heavy-flavour schemes
                      and used together with the inclusive production data at HERA
                      as input for QCD analyses to determine the charm running
                      mass in the \msbar renormalisation scheme and the optimal
                      values of the charm-quark mass parameters in other
                      heavy-flavour schemes.\newlineAn additional combination of
                      the H1 and ZEUS $D^{*+}$ visible cross sections was
                      performed to provide the combined cross sections without
                      theory-related uncertainties from the extrapolation
                      procedure. This combination also provides differential cross
                      sections as a function of the $D^{*+}$ kinematic variables.
                      Next-to-leading-order QCD predictions in the
                      fixed-flavour-number scheme were compared to the combined
                      $D^{*+}$ cross sections and a `customised' QCD calculation
                      was introduced in order to improve the agreement between the
                      central values of the theoretical predictions and the
                      data.\newlineWhile the HERA charm data are sensitive to the
                      gluon distribution in the proton at the values of partonic
                      fractions of the proton momenta $10^{-4}\lesssim x\lesssim
                      10^{-1}$, the production of charm quarks at LHCb probes the
                      region $5 \times 10^{-6}\lesssim x \lesssim 10^{-4}$. The
                      impact of recent LHCb measurements of heavy-flavour
                      production on parton distribution functions was studied in a
                      QCD analysis in the fixed-flavour-number scheme at
                      next-to-leading order. Differential cross sections of charm
                      and beauty production obtained by the LHCb experiment were
                      used together with the combined inclusive and heavy-flavour
                      production cross sections in deep inelastic scattering at
                      HERA. The heavy-flavour data of the LHCb experiment impose
                      constraints on the gluon and sea-quark distributions at very
                      low partonic fractions of the proton momenta. This kinematic
                      range is currently not covered by other experimental data in
                      QCD fits.\newlineAs the technical part of this thesis, the
                      ZEUS Event Display program has been modified in the context
                      of the ZEUS data preservation project to become independent
                      of the ZEUS Software. The new program is a pure ROOT
                      application. While it provides the main functionalities that
                      were available in the classic program, it does not require
                      any maintenance.},
      keywords     = {Dissertation (GND)},
      cin          = {ZEUS},
      cid          = {I:(DE-H253)ZEUS-20120806},
      pnm          = {611 - Fundamental Particles and Forces (POF3-611)},
      pid          = {G:(DE-HGF)POF3-611},
      experiment   = {EXP:(DE-588)4276505-5},
      typ          = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11 / PUB:(DE-HGF)15},
      url          = {https://bib-pubdb1.desy.de/record/208394},
}