Precise QCD predictions on top quark pair production mediated by massive   color octet vector boson at hadron colliders
  We present a theoretical framework for systematically calculating next-to-leading order (NLO) QCD effects to various experimental observables in models with massive COVB in a model independent way at hadron colliders. Specifically, we show the numerical results for the NLO QCD corrections to total cross sections, invariant mass distribution and AFB of top quark pairs production mediated by a massive COVB in both the fixed scale (top quark mass) scheme and the dynamical scale (top pair invariant mass) scheme. Our results show that the NLO QCD calculations in the dynamical scale scheme is more reasonable than the fixed scheme and the naive estimate of the NLO effects by simple rescaling of the LO results with the SM NLO K-factor is not appropriate. 
Hua Xing Zhu, Chong Sheng Li, Ding Yu Shao, Jian Wang, C.-P. Yuan
hep-ph