Implications of generalizedZ−Z′mixing

We discuss experimental implications of extending the gauge structure of the standard model to include an additional $U\left(1\right)\mathrm{}$ interaction broken at or near the weak scale. We work with the most general, renormalizable Lagrangian for the $\mathrm{SU}\left(2\right)\mathrm{}\times U\left(1\right)\mathrm{}\times U\left(1\right)\mathrm{}$ sector, with emphasis on the phenomenon of gauge kinetic mixing between the two $U\left(1\right)\mathrm{}$ gauge fields, and do not restrict ourselves to any of the “canonical” $Z^{\prime }$ models often discussed in the literature. Low-energy processes and $Z^0$-pole precision measurements are specifically addressed.