Cross Section and Forward-Backward Asymmetry of $t\bar{t}$ Production in the Model with Four Color Symmetry

Abstract

The contributions to the cross section ${\sigma }_{t\bar{t}}$ and to the forward-backward asymmetry $A_{\mathrm{FB}}^{t\bar{t}}$ of $t\bar{t}$ production at the Tevatron from $Z^{\prime }$-boson and scalar leptoquarks $S_a^{(\pm )}$ and scalar gluons $F_a$ predicted by the minimal model with four color quark-lepton symmetry are calculated. These contributions are shown to be small in tree approximation and can be significant with account of the 1-loop $gt\bar{t}$ effective vertex induced by the scalar doublets. The lower mass limit for scalar gluons $m_F\gtrsim 320GeV$ from the Tevatron data is obtained and it is shown that for $m_{F_1}\lesssim 990GeV$ the scalar gluon $F_1$ can be evident at LHC at the significance not less that $3\sigma$ (for $\sqrt{s}=14$ TeV, $L=10f{b}^{-1}$).

Comments: 11 pages, 5 figures. Submitted to Proceedings the 16th International Seminar on High Energy Physics "QUARKS-2010", Kolomna, Russia, 6-12 June, 2010