Resonance contribution of scalar color octet to $t \bar{t}$ production   at the LHC in the minimal four color quark-lepton symmetry model
  The scalar color octet contribution to the resonance $t\bar{t}$-pair production at the LHC is calculated and analysed with account of the one loop effective two gluon vertex. It is shown that this contribution from the scalar color octet $F_2$ predicted by the minimal model with the four color quark-lepton symmetry is for $\sqrt{s}=13$ TeV of about a few percents for $750 < m_{F_2} < 1800$ GeV and can exceed 10% for $400 < m_{F_2} < 750$ GeV. It is also pointed out that the search for the scalar octet $F_2$ as the resonance in the dijet mass spectra seems to be difficult because of the smallness of its one loop effective two gluon interaction. 
I. V. Frolov, M. V. Martynov, A. D. Smirnov
hep-ph