Electroweak prodution of top-quark pairs in e+e- annihilation at NNLO in   QCD: the vector contributions
  We report on a calculation of the vector current contributions to the electroweak production of top quark pairs in $e^+e^-$ annihilation at next-to-next-to-leading order in Quantum Chromodynamics. Our setup is fully differential and can be used to calculate any infrared-safe observable. The real emission contributions are handled by a next-to-next-to-leading order generalization of the phase-space slicing method. We demonstrate the power of our technique by considering its application to various inclusive and exclusive observables. 
Jun Gao, Hua Xing Zhu
hep-ph