Determination of $Z^{\prime }$ Gauge Couplings to Quarks and Leptons at Future Hadron Colliders

Abstract

We point out that at future hadron colliders the ratio of cross sections for $pp\to Z^{\prime }\to {\ell }^{+}{\ell }^{-}$ in two rapidity bins is a useful probe of the relative couplings of the $Z^{\prime }$ to $u$ and $d$ quarks. Combined with the forward-backward asymmetry, the rare decay modes $Z^{\prime }\to W\ell {\nu }_{\ell }$, and three associated productions $pp\to Z^{\prime }V$ ($V=Z,W,\gamma$), and assuming inter-family universality, small $Z-Z^{\prime }$ mixing, and the $Z^{\prime }$ charge commuting with the $S{U}_{2L}$ generators, three out of four normalized couplings could be extracted. An analysis of the statistical uncertainties expected for the above probes at the LHC for typical models with $M_{Z^{\prime }}\simeq 1$ 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.

Comments: (figures available on request), 12 pages, UPR-547-T