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@PHDTHESIS{Chen:696044,
      author       = {Chen, Long},
      othercontributors = {Bernreuther, Werner and Czakon, Michal},
      title        = {{H}eavy {Q}uark-{P}air {P}roduction in {E}lectron
                      {P}ositron {C}ollisions at {N}ext-to-{N}ext-to-{L}eading
                      {O}rder {QCD}},
      school       = {RWTH Aachen University},
      type         = {Dissertation},
      address      = {Aachen},
      reportid     = {RWTH-2017-06577},
      pages        = {1 Online-Ressource (iii, 148 Seiten) : Illustrationen,
                      Diagramme},
      year         = {2017},
      note         = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
                      University; Dissertation, RWTH Aachen University, 2017},
      abstract     = {Standard Model high-precision computations of observables
                      relatedto heavy quark physics are very important, both for
                      testing the consistency of Standard Model and for providing
                      a precision tool for data analysis in the context of
                      searches for new physics. The calculation of differential
                      cross sections and (exclusive) observables at higher order
                      perturbation theory in Quantum Chromodynamics (QCD) requires
                      a method for handling the soft and collinear singular
                      configurations that arise from the radiation of massless
                      partons and appear in individual contributions.In this
                      thesis, we present a set-up, within the antenna subtraction
                      framework, for computing the production of a massive
                      quark-antiquark pair in electron positron collisions at
                      next-to-next-to-leading order in the coupling $\alpha_s$ of
                      QCD at the differential level. Our set-up applies to the
                      calculation of any infrared-safe observable.We apply this
                      formalism to the production of top-quark pair $(\ttbar)$
                      production in the continuum and also to bottom-pair
                      $(\bbbar)$ production at the Z resonance. We compute the
                      respective production cross sections and several
                      distributions. We determine, in particular, the
                      forward-backward asymmetries $A_{\rm FB}^Q$of these heavy
                      quarks at order $\alpha_s^2$, which are important
                      observables for electroweak precision tests and for
                      determining the neutral-current couplingsof these quarks.
                      The order $\as^2$ corrections turn out to be significant.In
                      the top quark case we compute $A_{\rm FB}^t$ for several
                      center-of-mass energies above the $\ttbar$ production
                      threshold. For $\bbbar$ production at the $Z$ peak, we
                      compute $A_{\rm FB}^b$ both for the $b$-quark axis and the
                      oriented thrust axis definition of the asymmetry. We find
                      thatif one takes into account the complete massive order
                      $\as^2$ corrections to the leading-order asymmetry, which is
                      a new result, then the magnitude of the QCD
                      correctionsincreases slightly compared to previously known
                      results.This reduces the well-known tension between the
                      experimentally determinedbare $b$-quark asymmetry and the
                      value obtained by a global fit from $2.5\sigma$ to
                      $2.2\sigma$.},
      cin          = {136620 / 130000},
      ddc          = {530},
      cid          = {$I:(DE-82)136620_20140620$ / $I:(DE-82)130000_20140620$},
      typ          = {PUB:(DE-HGF)11},
      doi          = {10.18154/RWTH-2017-06577},
      url          = {https://publications.rwth-aachen.de/record/696044},
}