Determination of Z′ gauge couplings to quarks and leptons at future hadron colliders

We point out that at future hadron colliders the ratio of cross sections for pp→Z′→l+l- in two rapidity bins is a useful probe of the relative couplings of the Z′ to u and d quarks. Combined with the forward-backward asymmetry, the rare decay modes Z′→Wlνl, and three associated productions pp→Z′V (V=Z,W,γ), and assuming interfamily universality, small Z-Z′ mixing, and the Z′ charge commuting with the SU(2)L generators, three out of four normalized couplings could be extracted. An analysis of the statistical uncertainties expected for the above probes at the CERN LHC for typical models with MZ′1 TeV shows that one lepton coupling and two combinations of quark couplings could be determined to around 5%, 20%, and 30%, respectively. This allows for a clear distinction between models.