We consider current precision electroweak data, Z' searches and dark matter constraints and analyse their implications for an extension of the SM that includes an extra U(1)' massive gauge boson and a particular hidden sector ("hidden valley") with a confining (QCD-like) gauge group. The constraints on the Z' with arbitrary Z-Z' kinetic mixing coming from direct searches and precision tests of the Standard Model are analysed and shown to lead to a lower limit of 800 GeV on its mass. Renormalisable interactions involving the Z' probe the physics of the hidden valley sector which contains a pseudoscalar dark matter candidate. We find that dark matter constraints place an upper bound on the mass of the Z' of O(10) TeV. A TeV mass scale is needed for the hidden valley states, and the Sommerfeld factor for p-wave dark matter annihilation is found significantly to suppress the allowed parameter space of the model.
@article{arxiv.0903.1118,
title = {Electroweak and Dark Matter Constraints on a Z' in Models with a Hidden Valley},
author = {S. Cassel and D. M. Ghilencea and G. G. Ross},
journal= {arXiv preprint arXiv:0903.1118},
year = {2010}
}