Parameter Space of U(1) Neutral Gauge Bosons

We introduce a novel way to represent the parameter space for U(1) extensions of the Standard Model. In our framework, the free parameters include the mass \(M_{Z'}\) of the new neutral gauge boson \(Z'\), the associated gauge coupling (or, equivalently, the mixing angle between the Standard Model \(Z\) and the new \(Z'\) boson), and a suitably chosen ratio of the new U(1) gauge charges. Recent experimental data allow us to constrain these parameters over an approximate \(Z'\) mass range of \((10^{-2},10^4)\) GeV/\(c^2\). We also examine the role of the tree-level \(\rho \) parameter as an indirect constraint and discuss the prospects for \(Z'\) searches at future colliders. Abstract Published by the Jagiellonian University 2025 authors