The chiral color symmetry and $G'$-boson mass limit from new Tevatron data on $t \bar{t}$ production

A gauge model with chiral color symmetry of quarks is considered and possible effects of the color $G'$-boson octet predicted by this symmetry are investigated. The contributions of the $G'$-boson to the cross section $\sigma_{t\bar{t}}$ and to the forward-backward asymmetry $A_{\mathrm{FB}}^{p \bar p}$ of $t\bar{t}$ production at the Tevatron are calculated and analysed in dependence on two free parameters of the model, the mixing angle $\theta_G$ and $G'$ mass $m_{G'}$, in comparision with the new Tevatron data on $A_{\mathrm{FB}}^{p \bar p}$. The $G'$-boson contributions to $\sigma_{t\bar{t}}$ and $A_{\mathrm{FB}}^{p \bar p}$ are shown to be consistent with the Tevatron data on $\sigma_{t\bar{t}}$ and $A_{\mathrm{FB}}^{p \bar p}$, the allowed region in the $m_{G'} {-} \theta_G$ plane is discussed and around $m_{G'}=1.2$, $TeV$, $\theta_G=14^\circ $ the region of $1 \sigma$ consistency is found.