New color-octet axial vector boson revisited

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In this paper we re-examine how to utilize the previous proposed color-octet axial-vector boson Z C to explain the 3.4σ anomaly of t t forward-backward (FB) asymmetry A FB for mt t> 450GeV observed by CDF. Our numerical results indicate that the best-fit parameters are gₐq=0.07, gₐQ=3, and M C=440GeV, which are obtained by fitting the mass dependent A FB and total cross section data provided by a recent CDF measurement. Here gₐq (gₐQ) and M C are the axial couplings among Z C with the first two (the third) generation quarks, and Z C mass respectively. We also calculate one-side forward-backward asymmetry A OFB for top and bottom quark pair production at the LHC, focusing on the new contributions from Z C. Our studies show that A OFB can be utilized to measure the properties of new particle Z C.